Carnivorous wolves feed on nectar: Lifeform of the week

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For the first time, scientists have documented wolves – which are mostly carnivorous animals – feeding on the nectar of flowers. The protagonist of this story is the Ethiopian wolf (Canis simensis), which scientists saw feeding on the red hot poker flower (Kniphofia foliosa) in the Bale Mountains of southern Ethiopia. Researchers at the University of Oxford said on November 22, 2024, that this might be the first known plant-pollinator interaction involving a large carnivore.

And it wasn’t just a coincidence of a couple of wolves seen simply sniffing or licking the flowers. Numerous wolves from different packs came to the areas where these flowers bloom on a recurring basis and fed on up to 30 flowers on each visit.

Likewise, the scientists observed the adult wolves were not alone; their offspring accompanied them. This indicates the adults may be teaching the younger members of the group.

The scientists published their study in the peer-reviewed journal Ecology on November 19, 2024.

New allies in pollination?

When most people think of animals consuming nectar, they think of insects. And when little insects such as bees enter the flowers to feed, they become covered in pollen. Then they move from flower to flower to continue eating, and, as a result, spread the pollen. So we call these insects pollinators.

According to the study, up to 87% of flowers depend on a wide range of animals for pollination. And this includes mammals. Among flying mammals, the ones that do the most work are bats, and, what’s more, they do it on night shifts!

However, it seems that therophily, that is, pollination thanks to non-flying mammals, is more widespread and frequent than scientists knew. These mammalian pollinators are usually small or medium-sized arboreal species, while carnivorous animals are much less common.

In a 2015 study, scientists identified 343 mammals as pollinators, but only four of them were carnivores. And now we can add the largest carnivore ever seen feeding on pollen to this list: the Ethiopian wolf.

Fox-like animal licking a stalk of many tiny yellow flowers. There are many more flowers of the same type around.
Up to 87% of flowers depend on a wide range of animals for pollination, with insects being the most common pollinator. Only 4 carnivores were identified as pollinators. Now, we have to add the Ethiopian wolf to the list. Image via Adrien Lesaffre/ University of Oxford.

Carnivorous animals as pollinators?

Wolves may be rare as pollinators, but no less functional. When Ethiopian wolves lick nectar from flowers, their snouts become coated with pollen. Thus, the same thing happens as with insects, that is, they move to other flowers to continue eating and therefore move the pollen from one flower to another.

So, have we missed more examples of carnivorous species that feed on nectar? Or are animals changing their habits to adapt to new situations?

Lead author Sandra Lai, Ethiopian Wolf Conservation Program senior scientist based at the University of Oxford, wrote:

These findings highlight just how much we still have to learn about one of the world’s most-threatened carnivores. They also demonstrate the complexity of interactions between different species living on the beautiful Roof of Africa. This extremely unique and biodiverse ecosystem remains under threat from habitat loss and fragmentation.

Head of a dog-like animal licking a stalk of many tiny yellow flowers. It is orangish with a white throat.
For the first time, scientists have documented wolves feeding on the nectar of flowers. Image via Adrien Lesaffre/ University of Oxford.

A look at the lives of wolves

Wolves are highly social animals that live in families called packs. Each pack has a leader called an alpha, plus his partner. Normally, this pair is the only one that reproduces.

Families work as a team to catch large prey, and hardly any meat is wasted! On the other hand, when they are hungry, they can also feed on carrion, and of course, countless small animals. These impressive predators can run at a speed of 37 miles per hour (60 kph), as well as swim and travel long distances in the water.

They also have very good night vision, which allows them to hunt even in the dark. But they also have a highly developed sense of smell and can smell their prey from a distance of up to 1.2 miles (2 km). They have an acute sense of hearing and can hear sounds up to 6.2 miles (10 km) away.

Wolves are territorial animals and defend their territory with great ferocity, but they’re capable of sharing it with other packs as long as they have enough food and space.

Two brown, dog-like animals with pointy ears in a forest. In the background, trees with yellow leaves.
Wolves are social animals that live in packs. They are amazing hunters and defend their territory, but they also share it if there is food and space enough for more than one pack. Image via Wild Spirit/ Unsplash.

Wolves are intelligent and can learn and adapt

Wolves are intelligent creatures that can adapt to different environments and situations. In fact, they are able to solve complex problems and learn from experience because they have excellent memories, which allow them to survive in some of the most inhospitable places on the planet. Wolves live in diverse habitats such as the Arctic, deserts, woodlands and rainforests.

Wolves also carry out complex communication, using a variety of sounds and gestures to communicate. They howl, growl, bark and use body language. The lifespan of a wolf is around six to eight years in the wild, but they can live up to 16 years in captivity.

Unfortunately for wolves, many people see them as an enemy when they attack domestic livestock. So for decades, farmers and ranchers have killed them to protect their animals. However, wolves control high herbivore populations in the wild. The reintroduction of wolves in Yellowstone National Park beginning in 1995 has changed the ecosystem in the park, said YellowstonePark.com. It said the wolves returning to Yellowstone caused:

… a trophic cascade of ecological change, including helping to increase beaver populations and bring back aspen and vegetation.

Silver-gray dog-like animal licking the head of a small gray pup.
Wolves are intelligent, have an excellent memory and adapt to different environments and situations. All these characteristics allow them to survive in some inhospitable places. Image via M L/ Unsplash.

The Ethiopian wolf is the most endangered carnivore in Africa

The Ethiopian wolf is the rarest wild canid species in the world and the most endangered carnivore in Africa. Although wolves are beings that adapt easily to different situations, the Ethiopian wolf only lives in the highlands of Ethiopia. Fewer than 500 individuals survive, in 99 packs restricted to six Afro-Alpine enclaves. The People’s Trust for Endangered Species said:

The endangered wolves are threatened by habitat destruction and degradation, conflict with farmers and also by catching fatal diseases such as rabies and canine distemper virus (CDV) from the domestic dog populations. The latter can kill many of the wolves in a short space of time.

The Ethiopian Wolf Conservation Program (EWCP) was created in 1995 to protect wolves and their unique habitat. EWCP is the longest-running conservation program in Ethiopia, which aims to safeguard the future of natural habitats for the benefit of wildlife and people in the Ethiopian highlands.

Lithe orange-brown dog-like animal with pointy ears and long, thin legs, trotting across a barren landscape.
The Ethiopian wolf is the rarest wild canid species in the world and the most endangered carnivore in Africa. Image via Charles J. Sharp/ Wikipedia (CC BY-SA 4.0).

Bottom line: For the first time, scientists have documented carnivorous wolves feeding on nectar. Read more about wolves and see photos here.

Source: Canids as pollinators? Nectar foraging by Ethiopian wolves may contribute to the pollination of Kniphofia foliosa

Via University of Oxford

Read more: Bats, a spooky season icon, are our lifeform of the week

Read more: Vultures are the best clean-up crew: Lifeform of the week

The post Carnivorous wolves feed on nectar: Lifeform of the week first appeared on EarthSky.



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The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Makes a great gift. Get yours today!

For the first time, scientists have documented wolves – which are mostly carnivorous animals – feeding on the nectar of flowers. The protagonist of this story is the Ethiopian wolf (Canis simensis), which scientists saw feeding on the red hot poker flower (Kniphofia foliosa) in the Bale Mountains of southern Ethiopia. Researchers at the University of Oxford said on November 22, 2024, that this might be the first known plant-pollinator interaction involving a large carnivore.

And it wasn’t just a coincidence of a couple of wolves seen simply sniffing or licking the flowers. Numerous wolves from different packs came to the areas where these flowers bloom on a recurring basis and fed on up to 30 flowers on each visit.

Likewise, the scientists observed the adult wolves were not alone; their offspring accompanied them. This indicates the adults may be teaching the younger members of the group.

The scientists published their study in the peer-reviewed journal Ecology on November 19, 2024.

New allies in pollination?

When most people think of animals consuming nectar, they think of insects. And when little insects such as bees enter the flowers to feed, they become covered in pollen. Then they move from flower to flower to continue eating, and, as a result, spread the pollen. So we call these insects pollinators.

According to the study, up to 87% of flowers depend on a wide range of animals for pollination. And this includes mammals. Among flying mammals, the ones that do the most work are bats, and, what’s more, they do it on night shifts!

However, it seems that therophily, that is, pollination thanks to non-flying mammals, is more widespread and frequent than scientists knew. These mammalian pollinators are usually small or medium-sized arboreal species, while carnivorous animals are much less common.

In a 2015 study, scientists identified 343 mammals as pollinators, but only four of them were carnivores. And now we can add the largest carnivore ever seen feeding on pollen to this list: the Ethiopian wolf.

Fox-like animal licking a stalk of many tiny yellow flowers. There are many more flowers of the same type around.
Up to 87% of flowers depend on a wide range of animals for pollination, with insects being the most common pollinator. Only 4 carnivores were identified as pollinators. Now, we have to add the Ethiopian wolf to the list. Image via Adrien Lesaffre/ University of Oxford.

Carnivorous animals as pollinators?

Wolves may be rare as pollinators, but no less functional. When Ethiopian wolves lick nectar from flowers, their snouts become coated with pollen. Thus, the same thing happens as with insects, that is, they move to other flowers to continue eating and therefore move the pollen from one flower to another.

So, have we missed more examples of carnivorous species that feed on nectar? Or are animals changing their habits to adapt to new situations?

Lead author Sandra Lai, Ethiopian Wolf Conservation Program senior scientist based at the University of Oxford, wrote:

These findings highlight just how much we still have to learn about one of the world’s most-threatened carnivores. They also demonstrate the complexity of interactions between different species living on the beautiful Roof of Africa. This extremely unique and biodiverse ecosystem remains under threat from habitat loss and fragmentation.

Head of a dog-like animal licking a stalk of many tiny yellow flowers. It is orangish with a white throat.
For the first time, scientists have documented wolves feeding on the nectar of flowers. Image via Adrien Lesaffre/ University of Oxford.

A look at the lives of wolves

Wolves are highly social animals that live in families called packs. Each pack has a leader called an alpha, plus his partner. Normally, this pair is the only one that reproduces.

Families work as a team to catch large prey, and hardly any meat is wasted! On the other hand, when they are hungry, they can also feed on carrion, and of course, countless small animals. These impressive predators can run at a speed of 37 miles per hour (60 kph), as well as swim and travel long distances in the water.

They also have very good night vision, which allows them to hunt even in the dark. But they also have a highly developed sense of smell and can smell their prey from a distance of up to 1.2 miles (2 km). They have an acute sense of hearing and can hear sounds up to 6.2 miles (10 km) away.

Wolves are territorial animals and defend their territory with great ferocity, but they’re capable of sharing it with other packs as long as they have enough food and space.

Two brown, dog-like animals with pointy ears in a forest. In the background, trees with yellow leaves.
Wolves are social animals that live in packs. They are amazing hunters and defend their territory, but they also share it if there is food and space enough for more than one pack. Image via Wild Spirit/ Unsplash.

Wolves are intelligent and can learn and adapt

Wolves are intelligent creatures that can adapt to different environments and situations. In fact, they are able to solve complex problems and learn from experience because they have excellent memories, which allow them to survive in some of the most inhospitable places on the planet. Wolves live in diverse habitats such as the Arctic, deserts, woodlands and rainforests.

Wolves also carry out complex communication, using a variety of sounds and gestures to communicate. They howl, growl, bark and use body language. The lifespan of a wolf is around six to eight years in the wild, but they can live up to 16 years in captivity.

Unfortunately for wolves, many people see them as an enemy when they attack domestic livestock. So for decades, farmers and ranchers have killed them to protect their animals. However, wolves control high herbivore populations in the wild. The reintroduction of wolves in Yellowstone National Park beginning in 1995 has changed the ecosystem in the park, said YellowstonePark.com. It said the wolves returning to Yellowstone caused:

… a trophic cascade of ecological change, including helping to increase beaver populations and bring back aspen and vegetation.

Silver-gray dog-like animal licking the head of a small gray pup.
Wolves are intelligent, have an excellent memory and adapt to different environments and situations. All these characteristics allow them to survive in some inhospitable places. Image via M L/ Unsplash.

The Ethiopian wolf is the most endangered carnivore in Africa

The Ethiopian wolf is the rarest wild canid species in the world and the most endangered carnivore in Africa. Although wolves are beings that adapt easily to different situations, the Ethiopian wolf only lives in the highlands of Ethiopia. Fewer than 500 individuals survive, in 99 packs restricted to six Afro-Alpine enclaves. The People’s Trust for Endangered Species said:

The endangered wolves are threatened by habitat destruction and degradation, conflict with farmers and also by catching fatal diseases such as rabies and canine distemper virus (CDV) from the domestic dog populations. The latter can kill many of the wolves in a short space of time.

The Ethiopian Wolf Conservation Program (EWCP) was created in 1995 to protect wolves and their unique habitat. EWCP is the longest-running conservation program in Ethiopia, which aims to safeguard the future of natural habitats for the benefit of wildlife and people in the Ethiopian highlands.

Lithe orange-brown dog-like animal with pointy ears and long, thin legs, trotting across a barren landscape.
The Ethiopian wolf is the rarest wild canid species in the world and the most endangered carnivore in Africa. Image via Charles J. Sharp/ Wikipedia (CC BY-SA 4.0).

Bottom line: For the first time, scientists have documented carnivorous wolves feeding on nectar. Read more about wolves and see photos here.

Source: Canids as pollinators? Nectar foraging by Ethiopian wolves may contribute to the pollination of Kniphofia foliosa

Via University of Oxford

Read more: Bats, a spooky season icon, are our lifeform of the week

Read more: Vultures are the best clean-up crew: Lifeform of the week

The post Carnivorous wolves feed on nectar: Lifeform of the week first appeared on EarthSky.



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NASA testing underwater robots to explore ocean worlds

A roughly forearm-length, shark-shaped robot beneath the surface of a swimming pool, taken from an underwater camera.
Underwater robots like these – pictured during a pool test at Caltech in September 2024 – could one day explore subsurface oceans of icy moons. The testing showed the feasibility of a swarm of mini swimming robots. Image via NASA/ JPL-Caltech.
  • When NASA’s Europa Clipper reaches Jupiter in 2030, it’ll study the ocean that lies beneath the moon Europa’s icy crust from orbit.
  • NASA is already preparing for a possible follow-up mission, in which swimming robots could explore the watery depths of Europa and other ocean moons.
  • These engineers and scientists recently tested an autonomous prototype robot, which successfully explored a swimming pool.

NASA published this original story on November 20, 2024. Edits by EarthSky.

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Underwater robots under development

When NASA’s Europa Clipper reaches Jupiter in 2030, it will aim an array of powerful instruments toward Jupiter’s moon Europa. During 49 flybys, it’ll look down from orbit, hoping to spot any signs that the ocean beneath the moon’s icy crust might sustain life. But teams are already developing the next generation of spacecraft technology, which could potentially send underwater robots plunging into the watery depths of Europa and other ocean worlds.

In September 2024, a team at NASA’s Jet Propulsion Laboratory tested a series of underwater robot prototypes in a swimming pool at Caltech, Pasadena. And they say the results were encouraging.

The mission concept is called SWIM, short for Sensing With Independent Micro-Swimmers. The project envisions a swarm of dozens of self-propelled, cellphone-size swimming robots that, once delivered to a subsurface ocean by an ice-melting cryobot, would zoom off, looking for chemical and temperature signals that could indicate life.

Ethan Schaler, principal investigator for SWIM, said:

People might ask, why is NASA developing an underwater robot for space exploration? It’s because there are places we want to go in the solar system to look for life, and we think life needs water. So we need robots that can explore those environments autonomously, hundreds of millions of miles from home.


See the underwater robots in action in this video, via NASA/ JPL-Caltech.

SWIM practice

The SWIM team’s latest version is a 3D-printed plastic prototype that relies on low-cost, commercially made motors and electronics. Pushed along by two propellers, with four flaps for steering, the prototype demonstrated controlled maneuvering, the ability to stay on and correct its course, and a back-and-forth “lawnmower” exploration pattern. It managed all of this autonomously, without the team’s direct intervention. The robot even spelled out “J-P-L.”

Just in case the robot needed rescuing, it was attached to a fishing line, and an engineer toting a fishing rod trotted alongside the pool during each test. Nearby, a colleague reviewed the robot’s actions and sensor data on a laptop. The team completed more than 20 rounds of testing various prototypes at the pool and in a pair of tanks at JPL.

Schaler said:

It’s awesome to build a robot from scratch and see it successfully operate in a relevant environment. Underwater robots in general are very hard, and this is just the first in a series of designs we’d have to work through to prepare for a trip to an ocean world. But it’s proof that we can build these robots with the necessary capabilities and begin to understand what challenges they would face on a subsurface mission.

View of a glacier, with peaks in the distance next to a sun low in the horizon, tents on the right, and in the foreground on the ice, a complex dark capsule with orange rope, and a very small black triangle robot, emblazoned with the NASA logo.
A model of the final envisioned SWIM robot, right, sits beside a capsule holding an ocean-composition sensor. The sensor was tested on an Alaskan glacier in July 2023 through a JPL-led project called ORCAA (Ocean Worlds Reconnaissance and Characterization of Astrobiological Analogs). Image via NASA/ JPL-Caltech.

Tiny underwater robots

The wedge-shaped prototype used in most of the pool tests was about 16.5 inches (42 centimeters) long, weighing 5 pounds (2.3 kilograms). When ready for spaceflight, the robots would have dimensions about three times smaller. That’s tiny, compared to existing remotely operated and autonomous underwater scientific vehicles.

The palm-size swimmers would feature miniaturized, purpose-built parts. And they’d employ a novel sound-based communication system for transmitting data and triangulating their positions underwater.

Swarm science

Digital versions of these little robots got their own test, not in a pool but in a computer simulation. In an environment with the same pressure and gravity they would likely encounter on Europa, a virtual swarm of 5-inch-long (12-centimeter-long) robots repeatedly went looking for potential signs of life.

The computer simulations helped determine the limits of the robots’ abilities to collect science data in an unknown environment. And they led to the development of algorithms that would enable the swarm to explore more efficiently.

The simulations also helped the team better understand how to maximize science return while accounting for tradeoffs between battery life (up to two hours), the volume of water the swimmers could explore (about 3 million cubic feet, or 86,000 cubic meters), and the number of robots in a single swarm (a dozen, sent in four to five waves).

In addition, a team of collaborators at Georgia Tech in Atlanta fabricated and tested an ocean composition sensor that would enable each robot to simultaneously measure temperature, pressure, acidity or alkalinity, conductivity, and chemical makeup. Just a few millimeters square, the chip is the first to combine all those sensors in one tiny package.

More testing to come

Such an advanced concept would require several more years of work to be ready for a possible future flight mission to an icy moon. In the meantime, Schaler imagines SWIM robots potentially being further developed to do science work right here at home. They could be used to support oceanographic research, or take critical measurements underneath polar ice.

Bottom line: NASA is testing prototypes for underwater robots that could one day explore our solar system’s subsurface oceans.

Source: NASA Ocean World Explorers Have to Swim Before They Can Fly

Read more: Underwater robots to explore beneath Antarctic ice

The post NASA testing underwater robots to explore ocean worlds first appeared on EarthSky.



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A roughly forearm-length, shark-shaped robot beneath the surface of a swimming pool, taken from an underwater camera.
Underwater robots like these – pictured during a pool test at Caltech in September 2024 – could one day explore subsurface oceans of icy moons. The testing showed the feasibility of a swarm of mini swimming robots. Image via NASA/ JPL-Caltech.
  • When NASA’s Europa Clipper reaches Jupiter in 2030, it’ll study the ocean that lies beneath the moon Europa’s icy crust from orbit.
  • NASA is already preparing for a possible follow-up mission, in which swimming robots could explore the watery depths of Europa and other ocean moons.
  • These engineers and scientists recently tested an autonomous prototype robot, which successfully explored a swimming pool.

NASA published this original story on November 20, 2024. Edits by EarthSky.

The 2025 EarthSky Lunar Calendar is now available! Makes a great gift. Get yours today!

Underwater robots under development

When NASA’s Europa Clipper reaches Jupiter in 2030, it will aim an array of powerful instruments toward Jupiter’s moon Europa. During 49 flybys, it’ll look down from orbit, hoping to spot any signs that the ocean beneath the moon’s icy crust might sustain life. But teams are already developing the next generation of spacecraft technology, which could potentially send underwater robots plunging into the watery depths of Europa and other ocean worlds.

In September 2024, a team at NASA’s Jet Propulsion Laboratory tested a series of underwater robot prototypes in a swimming pool at Caltech, Pasadena. And they say the results were encouraging.

The mission concept is called SWIM, short for Sensing With Independent Micro-Swimmers. The project envisions a swarm of dozens of self-propelled, cellphone-size swimming robots that, once delivered to a subsurface ocean by an ice-melting cryobot, would zoom off, looking for chemical and temperature signals that could indicate life.

Ethan Schaler, principal investigator for SWIM, said:

People might ask, why is NASA developing an underwater robot for space exploration? It’s because there are places we want to go in the solar system to look for life, and we think life needs water. So we need robots that can explore those environments autonomously, hundreds of millions of miles from home.


See the underwater robots in action in this video, via NASA/ JPL-Caltech.

SWIM practice

The SWIM team’s latest version is a 3D-printed plastic prototype that relies on low-cost, commercially made motors and electronics. Pushed along by two propellers, with four flaps for steering, the prototype demonstrated controlled maneuvering, the ability to stay on and correct its course, and a back-and-forth “lawnmower” exploration pattern. It managed all of this autonomously, without the team’s direct intervention. The robot even spelled out “J-P-L.”

Just in case the robot needed rescuing, it was attached to a fishing line, and an engineer toting a fishing rod trotted alongside the pool during each test. Nearby, a colleague reviewed the robot’s actions and sensor data on a laptop. The team completed more than 20 rounds of testing various prototypes at the pool and in a pair of tanks at JPL.

Schaler said:

It’s awesome to build a robot from scratch and see it successfully operate in a relevant environment. Underwater robots in general are very hard, and this is just the first in a series of designs we’d have to work through to prepare for a trip to an ocean world. But it’s proof that we can build these robots with the necessary capabilities and begin to understand what challenges they would face on a subsurface mission.

View of a glacier, with peaks in the distance next to a sun low in the horizon, tents on the right, and in the foreground on the ice, a complex dark capsule with orange rope, and a very small black triangle robot, emblazoned with the NASA logo.
A model of the final envisioned SWIM robot, right, sits beside a capsule holding an ocean-composition sensor. The sensor was tested on an Alaskan glacier in July 2023 through a JPL-led project called ORCAA (Ocean Worlds Reconnaissance and Characterization of Astrobiological Analogs). Image via NASA/ JPL-Caltech.

Tiny underwater robots

The wedge-shaped prototype used in most of the pool tests was about 16.5 inches (42 centimeters) long, weighing 5 pounds (2.3 kilograms). When ready for spaceflight, the robots would have dimensions about three times smaller. That’s tiny, compared to existing remotely operated and autonomous underwater scientific vehicles.

The palm-size swimmers would feature miniaturized, purpose-built parts. And they’d employ a novel sound-based communication system for transmitting data and triangulating their positions underwater.

Swarm science

Digital versions of these little robots got their own test, not in a pool but in a computer simulation. In an environment with the same pressure and gravity they would likely encounter on Europa, a virtual swarm of 5-inch-long (12-centimeter-long) robots repeatedly went looking for potential signs of life.

The computer simulations helped determine the limits of the robots’ abilities to collect science data in an unknown environment. And they led to the development of algorithms that would enable the swarm to explore more efficiently.

The simulations also helped the team better understand how to maximize science return while accounting for tradeoffs between battery life (up to two hours), the volume of water the swimmers could explore (about 3 million cubic feet, or 86,000 cubic meters), and the number of robots in a single swarm (a dozen, sent in four to five waves).

In addition, a team of collaborators at Georgia Tech in Atlanta fabricated and tested an ocean composition sensor that would enable each robot to simultaneously measure temperature, pressure, acidity or alkalinity, conductivity, and chemical makeup. Just a few millimeters square, the chip is the first to combine all those sensors in one tiny package.

More testing to come

Such an advanced concept would require several more years of work to be ready for a possible future flight mission to an icy moon. In the meantime, Schaler imagines SWIM robots potentially being further developed to do science work right here at home. They could be used to support oceanographic research, or take critical measurements underneath polar ice.

Bottom line: NASA is testing prototypes for underwater robots that could one day explore our solar system’s subsurface oceans.

Source: NASA Ocean World Explorers Have to Swim Before They Can Fly

Read more: Underwater robots to explore beneath Antarctic ice

The post NASA testing underwater robots to explore ocean worlds first appeared on EarthSky.



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Do magnetic tornadoes drive dark ovals on Jupiter?

Magnetic tornadoes: Jupiter in blue and purple hues with a dark blue spot and brownish red patch at the south pole.
This is Jupiter in ultraviolet light. This image takes what we normally see in optical light as an orange- and cream-colored world … and turns it blue and lavender. But what’s that faintly darker oval inside the brownish patch around Jupiter’s south pole? Scientists think spots like that are haze stirred up by magnetic tornadoes. Image via Troy Tsubota and Michael Wong/ UC Berkeley.
  • Scientists discovered Earth-sized dark ovals near Jupiter’s poles, likely caused by magnetic tornadoes in its upper atmosphere which stir up thick haze layers.
  • These ovals, visible in ultraviolet images, appear about 75% of the time at the south pole and less frequently at the north, highlighting dynamic processes in Jupiter’s atmosphere.
  • The research connects Jupiter’s magnetic field, auroras, and deep atmospheric layers, revealing how magnetic and atmospheric forces interact across the planet.

Magnetic tornadoes and dark ovals

You’ve heard of Jupiter’s Great Red Spot (seen in dark blue in the ultraviolet image above). But how about the ephemeral, Earth-sized dark ovals by Jupiter’s poles? They might be an indication of processes in Jupiter’s magnetic field. Scientists said last week that these dark ovals are likely whipped up by a disturbance high in Jupiter’s ionosphere. They described a magnetic tornado stirring up the haze.

The dark ovals on Jupiter aren’t constant features … is anything in nature constant? The scientists analyzed yearly images that the Hubble Space Telescope captured between the years 2015 and 2022. In these ultraviolet-light images, a dark oval appears 75% of the time at Jupiter’s south pole. And, in eight images from Jupiter’s north pole, the scientists counted one dark oval.

The scientists said the Earth-sized ovals typically appear in Jupiter’s stratospheric layers, under the region where Jupiter’s bright auroras reside.

Jupiter has a strong magnetic field. The scientists said these dark ovals might indicate a process creating disturbances not just high in Jupiter’s atmosphere, but reaching deep into the atmosphere.

The peer-reviewed journal Nature Astronomy published the result of the scientists’ study on November 26, 2024.

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Makes a great gift. Get yours today!

A brown and orange marbled sphere is pictured with a bright blue swirl at the top.
The Hubble Space Telescope captured Jupiter’s bright auroras in 2016. The dark ovals appear in the same regions of Jupiter as the aurora. Image via NASA/ ESA/ J. Nichols (University of Leicester).

Jupiter’s dark ovals

Hubble first spotted these dark ovals in Jupiter’s atmosphere in the late 1990s. Hubble’s Outer Planet Atmospheres Legacy (OPAL) project takes yearly images of the gas giant planets in order to track their changing atmospheres. But the dark ovals on Jupiter haven’t drawn a lot of attention from scientists. Co-author Troy Tsubota of UC Berkeley said:

In the first two months, we realized these OPAL images were like a gold mine, in some sense, and I very quickly was able to construct this analysis pipeline and send all the images through to see what we get. That’s when we realized we could actually do some good science and real data analysis and start talking with collaborators about why these show up.

Magnetic tornadoes stir up the haze

Tsubota and co-author Michael Wong reached out to planetary atmospheric scientists to understand what might cause these dark ovals. Co-author Tom Stallard at Northumbria University in Newcastle-upon-Tyne in the U.K. suggested the ovals might be stirred up by magnetic tornadoes. Stallard had previously detected spinning in the Jovian ionosphere, which can create friction that leads to haze. Another source of atmospheric friction would be from the volcanic moon Io, which expels hot plasma that Jupiter’s magnetic field lines sweep up.

So the ovals likely come from the spinning atmosphere above in the way that a tornado on Earth reaches down to stir up the dusty landscape. Planetary atmospheric scientist and co-author Xi Zhang at UC Santa Cruz said:

The haze in the dark ovals is 50 times thicker than the typical concentration, which suggests it likely forms due to swirling vortex dynamics rather than chemical reactions triggered by high-energy particles from the upper atmosphere. Our observations showed that the timing and location of these energetic particles do not correlate with the appearance of the dark ovals.

Magnetic tornado: Bottom half of Jupiter in false color, showing the Great Red Spot in dark blue, for instance.
Here’s a closer look at just the southern hemisphere of Jupiter in false color. Note the reddish-brown oval inside the darker region. Scientists think this could be haze stirred up by a vortex higher up in the Jovian ionosphere. Image via Troy Tsubota and Michael Wong/ UC Berkeley.

A better understanding of Jupiter

Wong said:

Studying connections between different atmospheric layers is very important for all planets, whether it’s an exoplanet, Jupiter or Earth. We see evidence for a process connecting everything in the entire Jupiter system, from the interior dynamo to the satellites and their plasma tori to the ionosphere to the stratospheric hazes. Finding these examples helps us to understand the planet as a whole.

Bottom line: Scientists have analyzed dark ovals that appear near the poles on Jupiter. They believe magnetic tornadoes in higher atmospheric layers are stirring up the haze.

Source: UV-dark polar ovals on Jupiter as tracers of magnetosphere–atmosphere connections

Via UC Berkeley

Read more: Jupiter’s stormy weather on display in new Hubble images

The post Do magnetic tornadoes drive dark ovals on Jupiter? first appeared on EarthSky.



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Magnetic tornadoes: Jupiter in blue and purple hues with a dark blue spot and brownish red patch at the south pole.
This is Jupiter in ultraviolet light. This image takes what we normally see in optical light as an orange- and cream-colored world … and turns it blue and lavender. But what’s that faintly darker oval inside the brownish patch around Jupiter’s south pole? Scientists think spots like that are haze stirred up by magnetic tornadoes. Image via Troy Tsubota and Michael Wong/ UC Berkeley.
  • Scientists discovered Earth-sized dark ovals near Jupiter’s poles, likely caused by magnetic tornadoes in its upper atmosphere which stir up thick haze layers.
  • These ovals, visible in ultraviolet images, appear about 75% of the time at the south pole and less frequently at the north, highlighting dynamic processes in Jupiter’s atmosphere.
  • The research connects Jupiter’s magnetic field, auroras, and deep atmospheric layers, revealing how magnetic and atmospheric forces interact across the planet.

Magnetic tornadoes and dark ovals

You’ve heard of Jupiter’s Great Red Spot (seen in dark blue in the ultraviolet image above). But how about the ephemeral, Earth-sized dark ovals by Jupiter’s poles? They might be an indication of processes in Jupiter’s magnetic field. Scientists said last week that these dark ovals are likely whipped up by a disturbance high in Jupiter’s ionosphere. They described a magnetic tornado stirring up the haze.

The dark ovals on Jupiter aren’t constant features … is anything in nature constant? The scientists analyzed yearly images that the Hubble Space Telescope captured between the years 2015 and 2022. In these ultraviolet-light images, a dark oval appears 75% of the time at Jupiter’s south pole. And, in eight images from Jupiter’s north pole, the scientists counted one dark oval.

The scientists said the Earth-sized ovals typically appear in Jupiter’s stratospheric layers, under the region where Jupiter’s bright auroras reside.

Jupiter has a strong magnetic field. The scientists said these dark ovals might indicate a process creating disturbances not just high in Jupiter’s atmosphere, but reaching deep into the atmosphere.

The peer-reviewed journal Nature Astronomy published the result of the scientists’ study on November 26, 2024.

The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Makes a great gift. Get yours today!

A brown and orange marbled sphere is pictured with a bright blue swirl at the top.
The Hubble Space Telescope captured Jupiter’s bright auroras in 2016. The dark ovals appear in the same regions of Jupiter as the aurora. Image via NASA/ ESA/ J. Nichols (University of Leicester).

Jupiter’s dark ovals

Hubble first spotted these dark ovals in Jupiter’s atmosphere in the late 1990s. Hubble’s Outer Planet Atmospheres Legacy (OPAL) project takes yearly images of the gas giant planets in order to track their changing atmospheres. But the dark ovals on Jupiter haven’t drawn a lot of attention from scientists. Co-author Troy Tsubota of UC Berkeley said:

In the first two months, we realized these OPAL images were like a gold mine, in some sense, and I very quickly was able to construct this analysis pipeline and send all the images through to see what we get. That’s when we realized we could actually do some good science and real data analysis and start talking with collaborators about why these show up.

Magnetic tornadoes stir up the haze

Tsubota and co-author Michael Wong reached out to planetary atmospheric scientists to understand what might cause these dark ovals. Co-author Tom Stallard at Northumbria University in Newcastle-upon-Tyne in the U.K. suggested the ovals might be stirred up by magnetic tornadoes. Stallard had previously detected spinning in the Jovian ionosphere, which can create friction that leads to haze. Another source of atmospheric friction would be from the volcanic moon Io, which expels hot plasma that Jupiter’s magnetic field lines sweep up.

So the ovals likely come from the spinning atmosphere above in the way that a tornado on Earth reaches down to stir up the dusty landscape. Planetary atmospheric scientist and co-author Xi Zhang at UC Santa Cruz said:

The haze in the dark ovals is 50 times thicker than the typical concentration, which suggests it likely forms due to swirling vortex dynamics rather than chemical reactions triggered by high-energy particles from the upper atmosphere. Our observations showed that the timing and location of these energetic particles do not correlate with the appearance of the dark ovals.

Magnetic tornado: Bottom half of Jupiter in false color, showing the Great Red Spot in dark blue, for instance.
Here’s a closer look at just the southern hemisphere of Jupiter in false color. Note the reddish-brown oval inside the darker region. Scientists think this could be haze stirred up by a vortex higher up in the Jovian ionosphere. Image via Troy Tsubota and Michael Wong/ UC Berkeley.

A better understanding of Jupiter

Wong said:

Studying connections between different atmospheric layers is very important for all planets, whether it’s an exoplanet, Jupiter or Earth. We see evidence for a process connecting everything in the entire Jupiter system, from the interior dynamo to the satellites and their plasma tori to the ionosphere to the stratospheric hazes. Finding these examples helps us to understand the planet as a whole.

Bottom line: Scientists have analyzed dark ovals that appear near the poles on Jupiter. They believe magnetic tornadoes in higher atmospheric layers are stirring up the haze.

Source: UV-dark polar ovals on Jupiter as tracers of magnetosphere–atmosphere connections

Via UC Berkeley

Read more: Jupiter’s stormy weather on display in new Hubble images

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2024 Geminid meteor shower: All you need to know

Earth's globe with lines pointing towards the moon, sun and meteors overhead.
The 2024 Geminid meteor shower, seen in earth mode (above the earth’s surface, looking down). Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Predicted peak: is predicted** for 21 UTC on December 13, 2024.
When to watch: Since the radiant rises in mid-evening, you can watch for Geminids all night on December 13-14. The days before and after might be good as well. However, an almost full moon will compete with the Geminids in 2024. Luckily, a lot of Geminid meteors are bright. Find a way to block out the bright moon when watching the sky.
Overall duration of shower: November 19 to December 24.
Radiant: Rises in mid-evening, highest around 2 a.m. See chart.
Nearest moon phase: In 2024, the full moon falls at 9:02 UTC on December 15. So there will be a moonlit sky during the peak of the 2024 Geminid meteor shower.
Expected meteors at peak, under ideal conditions: Under a dark sky with no moon, you might catch 120 Geminid meteors per hour.
Note: The bold, white, bright Geminids give us one of the Northern Hemisphere’s best showers, especially in years when there’s no moon. They’re also visible, at lower rates, from the Southern Hemisphere. The meteors are plentiful, rivaling the August Perseids.

Report a fireball (very bright meteor) to the American Meteor Society: It’s fun and easy!

Geminid meteor shower parent comet

From the late, great Don Machholz (1952-2022), who discovered 12 comets …

An asteroid known as 3200 Phaethon is responsible for the Geminid meteor shower. This differs from most meteor showers, which result from comets, not asteroids. What’s the difference between a comet and an asteroid?

A comet is a dirty snowball, with a solid nucleus covered by a layer of ice which sublimates (turns from a solid to a gas) as the comet nears the sun. Comets are typically lightweight, with a density slightly heavier than water. They revolve around the sun in elongated orbits, going close to the sun, then going far from the sun. Seen through a telescope, a comet will show a coma, or head of the comet, as a nebulous patch of light around the nucleus, when it gets close to the sun. But when seen far from the sun, most comets appear star-like, because you see only the nucleus.

An asteroid is a rock. Typically, an asteroid’s orbit is more circular than that of a comet. Through a telescope an asteroid appears star-like.

These definitions worked well until a few decades ago. Larger telescopes began discovering asteroids far from the sun, and some of these objects, as they approached the sun, grew comas and tails, requiring the change of designation from asteroid to comet. For example, an odd object named Chiron, considered an asteroid when discovered in 1977, was reclassified as a comet in 1989 when it showed a coma. It orbits the sun every 50 years and travels from just inside the orbit of Saturn to the orbit of Uranus.

So an object initially considered an asteroid can be reclassified as a comet. Then, can the opposite occur? Can a comet be reclassified as an asteroid? Yes, it can. It is possible that a comet can shut down when its volatile materials become trapped beneath the nucleus’ surface. This is known as a dormant comet. When the comet loses all of its volatile materials, it is known as an extinct comet. The asteroid 3200 Phaethon seems to be an example of either a dormant or an extinct comet.

3200 Phaethon discovered in 1983

3200 Phaethon was discovered on images taken by IRAS (Infrared Astronomical Satellite) on October 11, 1983, by Simon Green and John Davies. Initially named 1983 TB, it was given an asteroid name, 3200 Phaethon, in 1985. After the orbit was calculated, Fred Whipple announced that this asteroid has the same orbit as the Geminid meteor shower. This was very unusual, since an asteroid had never been associated with a meteor shower. It is still not known how material from the asteroid’s surface, or interior, is released into the meteoroid stream.

3200 Phaethon gets very close to the sun, half of the distance of the innermost planet, Mercury. Then it ventures out past the orbit of Mars. So the meteor material intersects Earth’s orbit every mid-December, hence the Geminid meteor shower.

The Japanese spacecraft DESTINY+ (Demonstration and Experiment of Space Technology for Interplanetary Voyage with Phaethon Flyby and Dust Science) is expected to be launched in 2024 to visit the asteroid in 2028. One proposal from 2006 suggested crashing an object into 3200 Phaethon to produce an artificial meteor shower to better study the asteroid. DESTINY+, however, will not be hitting the asteroid.

But the particles from the asteroid will hit our atmosphere and you can see them this December.

Read more about asteroid Phaethon

Animated image of rotating roundish gray object on black background.
Radar images of near-Earth asteroid 3200 Phaethon generated by astronomers at the Arecibo Observatory on December 17, 2017. The 2017 encounter was the closest the asteroid will come to Earth until 2093. Image via NASA.

2024 Geminid meteor shower and the moon

The Geminid meteor shower – always a favorite among the annual meteor showers – is expected to peak in 2024 on December 13. The Geminids are a reliable shower, mostly for those who watch around 2 a.m. (your local time) from a dark-sky location. We also often hear from those who see Geminid meteors in the late evening hours. This year, a bright waxing gibbous moon will light up the sky. So you’ll have moonlit skies for viewing the meteor shower on those peak nights and mornings.

Geminid meteors tend to be bold, white and quick. Astronomer Guy Ottewell agrees these meteors tend to be bright. He offered this insight on his blog:

The Geminids, deriving from an asteroid rather than a comet, must include rock-sized pieces, which as they burn up in the atmosphere are often bright and do not leave trails.

He also said:

Following approximately the asteroid’s orbit, they cross inward close over Earth’s orbit almost sideways, from only slightly to the front, and slightly to the north. They appear to come at us from near Castor in the constellation of the Twins, and from this ‘radiant’ point their paths streak to any part of the sky. The radiant is up for almost all of the long (northern) winter night, highest at 2 a.m.

How many meteors, when to look

The zenithal hourly rate for this shower is 120. But you probably won’t see that many. On a dark night, near the peak of the shower around 2 a.m. (for all time zones), you can often catch 50 or more meteors per hour. During an optimum night for the Geminids, it’s possible to see 120 meteors – or more – per hour. So with moonlit skies in 2024, you might only catch the brightest meteors. Luckily, many of the Geminids are bright meteors. Try blocking out the moon when watching for meteors.

By the way, this shower favors Earth’s Northern Hemisphere, but it’s visible from the Southern Hemisphere, too. The curious rock comet called 3200 Phaethon is the Geminids’ parent body.

Green, yellow, orange and pink lights over the horizon. The lights are reflected in the water. There are 2 streaks on the right.
View at EarthSky Community Photos. | David Cox from the Deep River, Ontario, Canada, captured these meteors and aurora on December 13-14, 2023. David wrote: “A pair of Geminid meteors on either side of the handle of the Big Dipper captured in a single 6 second exposure. A beautiful aurora was dancing for several hours as the Geminid meteors flashed.” Thank you!

Geminid meteor shower radiant point

The Geminid meteor shower is best around 2 a.m. your local time because its radiant point – the point in our sky from which the meteors seem to radiate – is highest in the sky at that time. Generally, the higher the constellation Gemini the Twins climbs into your sky, the more Geminid meteors you’re likely to see.

The Geminids’ radiant point nearly coincides with the bright star Castor in Gemini. That’s a chance alignment, of course, as Castor lies about 52 light-years away, while these meteors burn up in the upper atmosphere some 60 miles (100 km) above Earth’s surface.

Castor is noticeably near another bright star, the golden star Pollux of Gemini. It’s fun to spot them, but you don’t need to find a meteor shower’s radiant point to see these meteors.

The meteors in annual showers appear in all parts of the sky. It’s even possible to have your back to the constellation Gemini and see a Geminid meteor fly by.

Geminid meteor shower: Sky chart showing the constellation Gemini with radial arrows near star Castor.
Watch the Geminid meteor shower around the morning of December 13, 2024. The meteors radiate from near the bright star Castor in the constellation Gemini the Twins, in the east on December evenings, highest around 2 a.m. your local time (time on your clock for all parts of the globe). In 2024, a bright waxing gibbous moon will interfere with viewing the meteor shower.
Sky chart with bright yellow radial lines in the constellation Gemini near labeled star Castor.
The 2024 Geminid meteor shower, seen in sky mode (from the the Earth’s surface, looking up). The radiant rises in the mid-evening (your local time) and it highest in the sky at 2 a.m. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

6 tips for Geminid meteor watchers

Many white streaks coming from the same direction, almost all in vertical.
View at EarthSky Community Photos. | Jan Curtis from Cheyenne, Wyoming, shared this composite image from December 14, 2023, – the morning after the Geminids’ peak – and wrote: “Despite the fog and wintery weather from December 12-14, last night was finally clear and I was able to catch the end of this year’s active Geminids. Taking 10s exposures for 10 hours, I was able to record about 69 meteors of which 42 are shown here. Bottle skies 5.0.” Thank you, Jan!

1. The most important thing, if you’re serious about watching meteors, is a dark, open sky.

2. The peak time of night for Geminids is around 2 a.m. for all parts of the globe. In 2024, a bright waxing gibbous moon will compete with meteors, so you will have moonlit skies for viewing the meteor shower. Try blocking out the moon from your viewing location. Visit Sunrise Sunset Calendars to find moonset times (be sure to check the moonset times box) for your specific location.

3. When you’re meteor-watching, it’s good to bring along a buddy. Then the two of you can watch in different directions. When someone sees one, call out, “Meteor!” This technique will let you see more meteors than one person watching alone will see.

4. Be sure to give yourself at least an hour (or more) of observing time. It takes about 20 minutes for your eyes to adapt to the dark.

5. Be aware that meteors often come in spurts, interspersed with lulls.

6. Special equipment? None needed. Maybe bring a sleeping bag to keep warm. A thermos with a warm drink and a snack are always welcome. Plan to sprawl back in a hammock, lawn chair, pile of hay or blanket on the ground. Lie back in comfort, and look upward. The meteors will appear in all parts of the sky.

Starry sky with many white, short streaks coming from the center of the image, to the sides. There is a windmill in the middle, where the streaks seem to separate.
View at EarthSky Community Photos. | Brian Mollenkopf from Lancaster, Ohio, created this composite image with photos taken on December 14, 2023. The windmill is just in the perfect place, right under the radiant point. Nice location and image! Thank you, Brian.

Watch for earthgrazers in the evening hours

If the 2 a.m. observing time isn’t practical for you, don’t give up! Sure, you won’t see as many Geminid meteors in the early evening, when the constellation Gemini sits close to the eastern horizon, but since the radiant rises mid-evening it’s worth a try. Plus, the evening hours are the best time to try and catch an earthgrazer.

An earthgrazer is a slooow-moving, looong-lasting meteor that travels horizontally across the sky. Earthgrazers are rare but prove to be especially memorable, if you should be lucky enough to catch one.

Orange streak with multiple large yellow dots along it in dark blue sky over wooded landscape.
Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image via Wikimedia Commons (public domain).

Bottom line: The 2024 Geminid meteor shower peaks overnight December 13-14 under moonlit skies. Try blocking out the moon light. Under ideal conditions you may see up to 120 meteors per hour.

**Predicted peak times and dates for meteor showers are from the American Meteor Society. Note that meteor shower peak times can vary.

Meteor showers: Tips for watching the show

The post 2024 Geminid meteor shower: All you need to know first appeared on EarthSky.



from EarthSky https://ift.tt/bIJSxfo
Earth's globe with lines pointing towards the moon, sun and meteors overhead.
The 2024 Geminid meteor shower, seen in earth mode (above the earth’s surface, looking down). Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

Predicted peak: is predicted** for 21 UTC on December 13, 2024.
When to watch: Since the radiant rises in mid-evening, you can watch for Geminids all night on December 13-14. The days before and after might be good as well. However, an almost full moon will compete with the Geminids in 2024. Luckily, a lot of Geminid meteors are bright. Find a way to block out the bright moon when watching the sky.
Overall duration of shower: November 19 to December 24.
Radiant: Rises in mid-evening, highest around 2 a.m. See chart.
Nearest moon phase: In 2024, the full moon falls at 9:02 UTC on December 15. So there will be a moonlit sky during the peak of the 2024 Geminid meteor shower.
Expected meteors at peak, under ideal conditions: Under a dark sky with no moon, you might catch 120 Geminid meteors per hour.
Note: The bold, white, bright Geminids give us one of the Northern Hemisphere’s best showers, especially in years when there’s no moon. They’re also visible, at lower rates, from the Southern Hemisphere. The meteors are plentiful, rivaling the August Perseids.

Report a fireball (very bright meteor) to the American Meteor Society: It’s fun and easy!

Geminid meteor shower parent comet

From the late, great Don Machholz (1952-2022), who discovered 12 comets …

An asteroid known as 3200 Phaethon is responsible for the Geminid meteor shower. This differs from most meteor showers, which result from comets, not asteroids. What’s the difference between a comet and an asteroid?

A comet is a dirty snowball, with a solid nucleus covered by a layer of ice which sublimates (turns from a solid to a gas) as the comet nears the sun. Comets are typically lightweight, with a density slightly heavier than water. They revolve around the sun in elongated orbits, going close to the sun, then going far from the sun. Seen through a telescope, a comet will show a coma, or head of the comet, as a nebulous patch of light around the nucleus, when it gets close to the sun. But when seen far from the sun, most comets appear star-like, because you see only the nucleus.

An asteroid is a rock. Typically, an asteroid’s orbit is more circular than that of a comet. Through a telescope an asteroid appears star-like.

These definitions worked well until a few decades ago. Larger telescopes began discovering asteroids far from the sun, and some of these objects, as they approached the sun, grew comas and tails, requiring the change of designation from asteroid to comet. For example, an odd object named Chiron, considered an asteroid when discovered in 1977, was reclassified as a comet in 1989 when it showed a coma. It orbits the sun every 50 years and travels from just inside the orbit of Saturn to the orbit of Uranus.

So an object initially considered an asteroid can be reclassified as a comet. Then, can the opposite occur? Can a comet be reclassified as an asteroid? Yes, it can. It is possible that a comet can shut down when its volatile materials become trapped beneath the nucleus’ surface. This is known as a dormant comet. When the comet loses all of its volatile materials, it is known as an extinct comet. The asteroid 3200 Phaethon seems to be an example of either a dormant or an extinct comet.

3200 Phaethon discovered in 1983

3200 Phaethon was discovered on images taken by IRAS (Infrared Astronomical Satellite) on October 11, 1983, by Simon Green and John Davies. Initially named 1983 TB, it was given an asteroid name, 3200 Phaethon, in 1985. After the orbit was calculated, Fred Whipple announced that this asteroid has the same orbit as the Geminid meteor shower. This was very unusual, since an asteroid had never been associated with a meteor shower. It is still not known how material from the asteroid’s surface, or interior, is released into the meteoroid stream.

3200 Phaethon gets very close to the sun, half of the distance of the innermost planet, Mercury. Then it ventures out past the orbit of Mars. So the meteor material intersects Earth’s orbit every mid-December, hence the Geminid meteor shower.

The Japanese spacecraft DESTINY+ (Demonstration and Experiment of Space Technology for Interplanetary Voyage with Phaethon Flyby and Dust Science) is expected to be launched in 2024 to visit the asteroid in 2028. One proposal from 2006 suggested crashing an object into 3200 Phaethon to produce an artificial meteor shower to better study the asteroid. DESTINY+, however, will not be hitting the asteroid.

But the particles from the asteroid will hit our atmosphere and you can see them this December.

Read more about asteroid Phaethon

Animated image of rotating roundish gray object on black background.
Radar images of near-Earth asteroid 3200 Phaethon generated by astronomers at the Arecibo Observatory on December 17, 2017. The 2017 encounter was the closest the asteroid will come to Earth until 2093. Image via NASA.

2024 Geminid meteor shower and the moon

The Geminid meteor shower – always a favorite among the annual meteor showers – is expected to peak in 2024 on December 13. The Geminids are a reliable shower, mostly for those who watch around 2 a.m. (your local time) from a dark-sky location. We also often hear from those who see Geminid meteors in the late evening hours. This year, a bright waxing gibbous moon will light up the sky. So you’ll have moonlit skies for viewing the meteor shower on those peak nights and mornings.

Geminid meteors tend to be bold, white and quick. Astronomer Guy Ottewell agrees these meteors tend to be bright. He offered this insight on his blog:

The Geminids, deriving from an asteroid rather than a comet, must include rock-sized pieces, which as they burn up in the atmosphere are often bright and do not leave trails.

He also said:

Following approximately the asteroid’s orbit, they cross inward close over Earth’s orbit almost sideways, from only slightly to the front, and slightly to the north. They appear to come at us from near Castor in the constellation of the Twins, and from this ‘radiant’ point their paths streak to any part of the sky. The radiant is up for almost all of the long (northern) winter night, highest at 2 a.m.

How many meteors, when to look

The zenithal hourly rate for this shower is 120. But you probably won’t see that many. On a dark night, near the peak of the shower around 2 a.m. (for all time zones), you can often catch 50 or more meteors per hour. During an optimum night for the Geminids, it’s possible to see 120 meteors – or more – per hour. So with moonlit skies in 2024, you might only catch the brightest meteors. Luckily, many of the Geminids are bright meteors. Try blocking out the moon when watching for meteors.

By the way, this shower favors Earth’s Northern Hemisphere, but it’s visible from the Southern Hemisphere, too. The curious rock comet called 3200 Phaethon is the Geminids’ parent body.

Green, yellow, orange and pink lights over the horizon. The lights are reflected in the water. There are 2 streaks on the right.
View at EarthSky Community Photos. | David Cox from the Deep River, Ontario, Canada, captured these meteors and aurora on December 13-14, 2023. David wrote: “A pair of Geminid meteors on either side of the handle of the Big Dipper captured in a single 6 second exposure. A beautiful aurora was dancing for several hours as the Geminid meteors flashed.” Thank you!

Geminid meteor shower radiant point

The Geminid meteor shower is best around 2 a.m. your local time because its radiant point – the point in our sky from which the meteors seem to radiate – is highest in the sky at that time. Generally, the higher the constellation Gemini the Twins climbs into your sky, the more Geminid meteors you’re likely to see.

The Geminids’ radiant point nearly coincides with the bright star Castor in Gemini. That’s a chance alignment, of course, as Castor lies about 52 light-years away, while these meteors burn up in the upper atmosphere some 60 miles (100 km) above Earth’s surface.

Castor is noticeably near another bright star, the golden star Pollux of Gemini. It’s fun to spot them, but you don’t need to find a meteor shower’s radiant point to see these meteors.

The meteors in annual showers appear in all parts of the sky. It’s even possible to have your back to the constellation Gemini and see a Geminid meteor fly by.

Geminid meteor shower: Sky chart showing the constellation Gemini with radial arrows near star Castor.
Watch the Geminid meteor shower around the morning of December 13, 2024. The meteors radiate from near the bright star Castor in the constellation Gemini the Twins, in the east on December evenings, highest around 2 a.m. your local time (time on your clock for all parts of the globe). In 2024, a bright waxing gibbous moon will interfere with viewing the meteor shower.
Sky chart with bright yellow radial lines in the constellation Gemini near labeled star Castor.
The 2024 Geminid meteor shower, seen in sky mode (from the the Earth’s surface, looking up). The radiant rises in the mid-evening (your local time) and it highest in the sky at 2 a.m. Chart via Guy Ottewell’s 2024 Astronomical Calendar. Used with permission.

6 tips for Geminid meteor watchers

Many white streaks coming from the same direction, almost all in vertical.
View at EarthSky Community Photos. | Jan Curtis from Cheyenne, Wyoming, shared this composite image from December 14, 2023, – the morning after the Geminids’ peak – and wrote: “Despite the fog and wintery weather from December 12-14, last night was finally clear and I was able to catch the end of this year’s active Geminids. Taking 10s exposures for 10 hours, I was able to record about 69 meteors of which 42 are shown here. Bottle skies 5.0.” Thank you, Jan!

1. The most important thing, if you’re serious about watching meteors, is a dark, open sky.

2. The peak time of night for Geminids is around 2 a.m. for all parts of the globe. In 2024, a bright waxing gibbous moon will compete with meteors, so you will have moonlit skies for viewing the meteor shower. Try blocking out the moon from your viewing location. Visit Sunrise Sunset Calendars to find moonset times (be sure to check the moonset times box) for your specific location.

3. When you’re meteor-watching, it’s good to bring along a buddy. Then the two of you can watch in different directions. When someone sees one, call out, “Meteor!” This technique will let you see more meteors than one person watching alone will see.

4. Be sure to give yourself at least an hour (or more) of observing time. It takes about 20 minutes for your eyes to adapt to the dark.

5. Be aware that meteors often come in spurts, interspersed with lulls.

6. Special equipment? None needed. Maybe bring a sleeping bag to keep warm. A thermos with a warm drink and a snack are always welcome. Plan to sprawl back in a hammock, lawn chair, pile of hay or blanket on the ground. Lie back in comfort, and look upward. The meteors will appear in all parts of the sky.

Starry sky with many white, short streaks coming from the center of the image, to the sides. There is a windmill in the middle, where the streaks seem to separate.
View at EarthSky Community Photos. | Brian Mollenkopf from Lancaster, Ohio, created this composite image with photos taken on December 14, 2023. The windmill is just in the perfect place, right under the radiant point. Nice location and image! Thank you, Brian.

Watch for earthgrazers in the evening hours

If the 2 a.m. observing time isn’t practical for you, don’t give up! Sure, you won’t see as many Geminid meteors in the early evening, when the constellation Gemini sits close to the eastern horizon, but since the radiant rises mid-evening it’s worth a try. Plus, the evening hours are the best time to try and catch an earthgrazer.

An earthgrazer is a slooow-moving, looong-lasting meteor that travels horizontally across the sky. Earthgrazers are rare but prove to be especially memorable, if you should be lucky enough to catch one.

Orange streak with multiple large yellow dots along it in dark blue sky over wooded landscape.
Painting of 1860 earthgrazer fireball by Frederic Edwin Church. Image via Wikimedia Commons (public domain).

Bottom line: The 2024 Geminid meteor shower peaks overnight December 13-14 under moonlit skies. Try blocking out the moon light. Under ideal conditions you may see up to 120 meteors per hour.

**Predicted peak times and dates for meteor showers are from the American Meteor Society. Note that meteor shower peak times can vary.

Meteor showers: Tips for watching the show

The post 2024 Geminid meteor shower: All you need to know first appeared on EarthSky.



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December birthstone: turquoise, zircon or tanzanite

About 40 pieces of the December birthstone turquoise, all polished, mostly oval but a few rectangular, scattered on a white surface. Each piece has different shades of green with brown veining.
The December birthstone, turquoise, from Nishapur in northeastern Iran. Image via Sonia Sevilla/ Wikimedia Commons (CC0 1.0).

If you’re born in December, you have a choice of three birthstones: turquoise, zircon or tanzanite. Turquoise, a soft gemstone used in jewelry and ornaments, has a rich history dating to antiquity. Zircons are not well-known gemstones, but they make absolutely stunning jewelry. Tanzanite is an exquisite clear blue-violet crystal found only in Tanzania.

Why do some months have one birthstone but others have two or three? According to the website onecklace.com, multiple stones for some months allow more affordable options in addition to the traditional and more expensive stones.

The 2025 EarthSky lunar calendar makes a great gift. Get yours today!

December birthstone: turquoise

To chemists and geologists, turquoise is copper aluminum phosphate. It forms when rainwater or melted snow percolates through copper ore deposits called copper porphyry. Water interacts with copper sulfides in the ore to form an acidic solution. This copper-carrying acidic water, when it reacts with aluminum and potassium in the rocks, precipitates turquoise into cavities. You can find turquoise in weathered volcanic rock and sedimentary rock in arid locations.

Turquoise is a relatively soft gemstone, with a Mohs scale hardness of five to six. You can scratch or break turquoise with moderate force. Oil and pigments easily discolor this porous opaque stone. It also changes color when it loses some of its water content.

Hard, relatively non-porous, compact stones have the best appearance because the stone can be finely polished. “Softer” varieties that are more porous are treated with oil, paraffin, liquid plastic or water glass to enhance its durability and color.

Copper gives a sky-blue shade to turquoise, while iron gives it a greener tone. The most valued variety of turquoise is an intense sky-blue color, like the color of a robin’s egg. Ochre and brown-black veins, often found in the gemstones, are inclusions from the surrounding rock matrix.

Turquoise facts

Some of the best turquoise in the world comes from Iran, famous for its sky-blue stones from Neyshabur. In Egypt, people have mined turquoise in the Sinai Peninsula for over 5,000 years. Turquoise is found in many U.S. southwestern states: Arizona, California, Colorado, New Mexico and Nevada. This stone also occurs in Afghanistan, Australia, China, India, Tibet, Mexico and Brazil.

A rock of various shades of beige and brown, cut to reveal light blue turquoise in the middle that has beige veining.
Turquoise from Cerillos, New Mexico, part of a collection at the Smithsonian Museum of Natural History. Image via Tim Evanson/ Wikimedia Commons (CC BY-SA 2.0).

The word turquoise originated from the French phrase pierre turquoise, meaning Turkish stone. That’s because Venetian traders brought the gemstone to Europe after acquiring it from traders in Turkey.

In antiquity, turquoise was used as jewelry by the ruling classes of civilizations in Africa, Asia and the Americas. People have found beads dating to the late 6th millennium BCE in ancient Iraq. Turquoise bracelets were on the arm of a woman in the tomb of Zer, a pharaoh that ruled Egypt around 3000 BCE. A 3,700-year-old dragon relic from the Xia Dynasty, made from over 2,000 pieces of turquoise, was in the tomb of a nobleman in central China.

Turquoise in the Americas

Turquoise has a rich history in the American Southwest. Native Americans have been using this gemstone to create jewelry and ornamental pieces for several thousand years. The Apache, Navajo, Pueblo, and Zuni are known for their turquoise jewelry.

In the Zuni language, the word for turquoise is sky stone. During the growing season in summer, Pueblo dancers wear turquoise to encourage rainfall. The Navajo associate turquoise with health and protection, using the stone in important rites of passage. While the Apache believed that turquoise lay at the end of a rainbow, and that turquoise attached to a bow or gun ensured an accurate aim.

Turquoise was a part of pre-Columbian cultures in Mexico, Central America, and South America. In Peru, prehistoric tribes made small objects such as beads, figurines and artifacts with turquoise inlays. For the Aztecs, turquoise was popular in ornaments. It also had important religious and ceremonial uses. For example, a high priest involved in human sacrifice wore a turquoise pendant hung from his underlip. A notable Aztec art form was intricate turquoise mosaics, like that of a turquoise mosaic mask used in the interment of a king.

Turquoise lore

Some people consider turquoise a love charm. When received as a gift, it is supposed to symbolize a pledge of affection. Shakespeare used this lore in “The Merchant of Venice.” In it, Leah gave a turquoise ring to Shylock when he was a bachelor, hoping it would win his affections so he would ask her to marry him.

There are many other superstitions associated with turquoise. In the twelfth century, an Arabian writing declared: “the turquoise shines when the air is pure and becomes pale when it is dim.” They also believed that its color changed with the weather. In the 13th century, people believed it would protect its owner from injury if he fell off a horse.

George Frederick Kunz’s book, The Curious Lore of Precious Stones, stated that diamonds and turquoises supposedly lost their powers if sold:

The spirit dwelling in the stone was thought to take offence at the idea of being bought and sold, and was supposed to depart from the stone, leaving it nothing more than a bit of senseless matter. If, however, the diamond (or turquoise) were offered as a pledge of love or friendship, the spirit was quite willing to transfer its good offices from one owner to another.

There were also health myths associated with turquoise. People believed the stone changed color when its wearer became ill. Some said it was an effective treatment for scorpion stings and pain from evil influences. Just looking at turquoise supposedly strengthen the eyes.

December birthstone: zircon

Several red zircon crystals embedded in a mostly quartz matrix. The entire piece measures about 2.1 cm (0.8 inches) in diameter. Image via Robert M. Lavinsky/ Wikimedia Commons (CC BY-SA 3.0).

Zircon is a mineral formed of the elements zirconium and silicon (zirconium silicate). Most igneous rocks contain small crystals, just a few millimeters in size. With a Mohs scale hardness of 7.5, zircon is hard enough to survive the geologic forces that create metamorphic and sedimentary rock. But large zircon crystals are rare. They’re formed mainly in pegmatites (coarse-grained igneous rock) and carbonatites. But due to weathering of gem-bearing rocks, most zircons are in alluvial and beach deposits.

The name zircon may have come from the Arabic words zarquin, meaning red. Or perhaps from the Persian word zargus, meaning gold-colored.

Major sources of gemstone-quality zircon are Thailand, Cambodia, Vietnam and Sri Lanka. The gemstones also occur in Myanmar, France, Norway, Australia and Canada.

Colors of zircon

Over vast spans of geologic time, forces have worked within zirconium silicate crystals to change their molecular structure and color. Uranium and thorium inclusions emit radiation that alters the original crystal structure. A glass-like material forms, with colors of red to brown, orange and yellow. Green is the rarest of the natural colors. Since the 1920s, most gemstones have undergone heat treatment to bring out their colors. This produces colorless zircons, as well as blue and golden stones.

Eight small round cut zircon gemstones. One is clear, three are different shades of red, and four are different shades of yellow.
Cut zircon stones from Vietnam. Image via Robert M. Lavinsky / Wikimedia Commons (CC BY-SA 3.0).

The creation of blue stones is in an interesting story relayed in “Gems and Crystals” by Anna S. Sofianides and George E. Harlow:

In the 1920s, a new blue gemstone suddenly appeared in the market. Endowed with spectacular brilliance, it was an immediate hit.

The creation of the blue zircon

The gems, it turned out, were zircons, normally brown to green, but never before blue. George F. Kunz, the legendary Tiffany gemologist, immediately suspected trickery; not only were there extraordinary stones available in abundance, but they were available all over the world! Upon Kunz’s behest, a colleague made inquiries during a trip to Siam (Thailand) and learned that a large deposit of unattractive brown zircon had stimulated color-improvement experimentation by local entrepreneurs. Heating in an oxygen-free environment made the drab material into “new” blue stones, which vendors sent to outlets worldwide. Even after finding out about the deception, the market simply accepted the information and the demand for the new gems continued unabated.

The blue stones are a clear favorite among zircon customers. Red and green colors are also valuable. Colorless zircons are excellent imitators of diamonds, in appearance only, with a brilliant fire almost as dazzling as the real thing. However, zircon can be brittle and cutting takes great care. It breaks with a well-placed knock, due to internal stresses in the crystal caused by radiation damage and heat treatment. But it remains in demand for its stunning beauty. In addition, other factors that affect pricing of the gemstones are clarity and an absence of visible inclusions.

Zircon lore

Green zircon was among the stones of the Kalpa Tree of the Hindu religion, where it represented the tree’s foliage. This tree was a symbolic offering to the gods. Hindu poets of the 19th century described it as part of a glowing ensemble of precious stones that also included sapphires, diamonds and topaz.

The hyacinth and jacinth, reddish-brown and orange-red varieties of zircon, were a favorite stone of ancient Arabs, even mentioned in the famed “Arabian Nights.”

During the 14th century, zircon was popular as a safeguard against the Black Death, the great plague that wiped out a quarter of the population of Europe. People believed the stone possessed healing powers: to induce sleep, as an antidote against poison, and as an aid to digestion.

A zircon shaped mostly like a rectangle except that the top is pointed. The entire crystal is olive-green.
A rare olive-green zircon, measuring about 3.4 cm (1.3 inches) in length, from Myanmar. Image via Robert M. Lavinsky/ Wikimedia Commons (CC BY-SA 3.0).

December birthstone: tanzanite

A rugged transparent light blue-violet rock with some transparent white regions.
A tanzanite crystal from the Merelani Hills, Arusha Region, Tanzania. Image via Parent Géry/ Wikimedia Commons (CC BY-SA 3.0).

Tanzanite is an unusual form of the mineral zoisite (calcium aluminium hydroxyl sorosilicate). Its colors, blue and violet, are due to the presence of vanadium in the zoisite crystals. This gemstone formed 585 million years ago under extreme heat during intense plate tectonic activity, in a place that would someday become Mount Kilimanjaro in northern Tanzania.

Today, you can only find tanzanite in the Merelani Hills near the foot of Mount Kilimanjaro.

Colors from different angles

In its natural form, tanzanite appears brown, yellowish green, blue and violet, flashing these colors when viewed from different angles. This phenomenon is pleochroism, where you can see different colors depending on how light hits the gemstone.

The type of lighting can also make a difference. Under fluorescent lights, tanzanite appears bluer, while under incandescent light, more violet hues emerge.

However, most crystals used in jewelry received doses of heat to remove the brownish color found in the natural tanzanite. The results are more intensely blue and violet gems. On rare occasions, heated stones can produce a green gem with secondary blue and violet colors. For cut gems, cutters can influence their overall color by how they craft the gem.

Tanzanite’s recent history

While most birthstones have histories spanning hundreds and even thousands of years, tanzanite’s story began in 1967. A Masai tribesman found unusual clear violet-blue crystals in the Merelani Hills in northern Tanzania. He notified a local tailor and prospector, Manuel d’Souza, who, upon finding the gemstones, filed the first of many mining claims.

Initially, d’Souza thought they were sapphires. But no one knew for sure. The stones made their way to geologists at the Gemological Institute of America where they identified them as an unusual form of zoisite.

And then, the famed jewelry purveyors, Tiffany & Company, took an interest in the gem. In 1968, they began a marketing campaign. To make the gems more appealing to buyers, they renamed blue zoisite to tanzanite, in honor of its country of origin. Finally, in 2002, the American Gem Trade Association selected tanzanite to join turquoise and zircon as December birthstones.

Beyond the December birthstone: birthstones for all months

January birthstone
February birthstone
March birthstone
April birthstone
May birthstone
June birthstone
July birthstone
August birthstone
September birthstone
October birthstone
November birthstone
December birthstone

Bottom line: December babies are fortunate enough to have three choices for their birthstone. Turquoise, zircon and tanzanite are the birthstones for December.

The post December birthstone: turquoise, zircon or tanzanite first appeared on EarthSky.



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About 40 pieces of the December birthstone turquoise, all polished, mostly oval but a few rectangular, scattered on a white surface. Each piece has different shades of green with brown veining.
The December birthstone, turquoise, from Nishapur in northeastern Iran. Image via Sonia Sevilla/ Wikimedia Commons (CC0 1.0).

If you’re born in December, you have a choice of three birthstones: turquoise, zircon or tanzanite. Turquoise, a soft gemstone used in jewelry and ornaments, has a rich history dating to antiquity. Zircons are not well-known gemstones, but they make absolutely stunning jewelry. Tanzanite is an exquisite clear blue-violet crystal found only in Tanzania.

Why do some months have one birthstone but others have two or three? According to the website onecklace.com, multiple stones for some months allow more affordable options in addition to the traditional and more expensive stones.

The 2025 EarthSky lunar calendar makes a great gift. Get yours today!

December birthstone: turquoise

To chemists and geologists, turquoise is copper aluminum phosphate. It forms when rainwater or melted snow percolates through copper ore deposits called copper porphyry. Water interacts with copper sulfides in the ore to form an acidic solution. This copper-carrying acidic water, when it reacts with aluminum and potassium in the rocks, precipitates turquoise into cavities. You can find turquoise in weathered volcanic rock and sedimentary rock in arid locations.

Turquoise is a relatively soft gemstone, with a Mohs scale hardness of five to six. You can scratch or break turquoise with moderate force. Oil and pigments easily discolor this porous opaque stone. It also changes color when it loses some of its water content.

Hard, relatively non-porous, compact stones have the best appearance because the stone can be finely polished. “Softer” varieties that are more porous are treated with oil, paraffin, liquid plastic or water glass to enhance its durability and color.

Copper gives a sky-blue shade to turquoise, while iron gives it a greener tone. The most valued variety of turquoise is an intense sky-blue color, like the color of a robin’s egg. Ochre and brown-black veins, often found in the gemstones, are inclusions from the surrounding rock matrix.

Turquoise facts

Some of the best turquoise in the world comes from Iran, famous for its sky-blue stones from Neyshabur. In Egypt, people have mined turquoise in the Sinai Peninsula for over 5,000 years. Turquoise is found in many U.S. southwestern states: Arizona, California, Colorado, New Mexico and Nevada. This stone also occurs in Afghanistan, Australia, China, India, Tibet, Mexico and Brazil.

A rock of various shades of beige and brown, cut to reveal light blue turquoise in the middle that has beige veining.
Turquoise from Cerillos, New Mexico, part of a collection at the Smithsonian Museum of Natural History. Image via Tim Evanson/ Wikimedia Commons (CC BY-SA 2.0).

The word turquoise originated from the French phrase pierre turquoise, meaning Turkish stone. That’s because Venetian traders brought the gemstone to Europe after acquiring it from traders in Turkey.

In antiquity, turquoise was used as jewelry by the ruling classes of civilizations in Africa, Asia and the Americas. People have found beads dating to the late 6th millennium BCE in ancient Iraq. Turquoise bracelets were on the arm of a woman in the tomb of Zer, a pharaoh that ruled Egypt around 3000 BCE. A 3,700-year-old dragon relic from the Xia Dynasty, made from over 2,000 pieces of turquoise, was in the tomb of a nobleman in central China.

Turquoise in the Americas

Turquoise has a rich history in the American Southwest. Native Americans have been using this gemstone to create jewelry and ornamental pieces for several thousand years. The Apache, Navajo, Pueblo, and Zuni are known for their turquoise jewelry.

In the Zuni language, the word for turquoise is sky stone. During the growing season in summer, Pueblo dancers wear turquoise to encourage rainfall. The Navajo associate turquoise with health and protection, using the stone in important rites of passage. While the Apache believed that turquoise lay at the end of a rainbow, and that turquoise attached to a bow or gun ensured an accurate aim.

Turquoise was a part of pre-Columbian cultures in Mexico, Central America, and South America. In Peru, prehistoric tribes made small objects such as beads, figurines and artifacts with turquoise inlays. For the Aztecs, turquoise was popular in ornaments. It also had important religious and ceremonial uses. For example, a high priest involved in human sacrifice wore a turquoise pendant hung from his underlip. A notable Aztec art form was intricate turquoise mosaics, like that of a turquoise mosaic mask used in the interment of a king.

Turquoise lore

Some people consider turquoise a love charm. When received as a gift, it is supposed to symbolize a pledge of affection. Shakespeare used this lore in “The Merchant of Venice.” In it, Leah gave a turquoise ring to Shylock when he was a bachelor, hoping it would win his affections so he would ask her to marry him.

There are many other superstitions associated with turquoise. In the twelfth century, an Arabian writing declared: “the turquoise shines when the air is pure and becomes pale when it is dim.” They also believed that its color changed with the weather. In the 13th century, people believed it would protect its owner from injury if he fell off a horse.

George Frederick Kunz’s book, The Curious Lore of Precious Stones, stated that diamonds and turquoises supposedly lost their powers if sold:

The spirit dwelling in the stone was thought to take offence at the idea of being bought and sold, and was supposed to depart from the stone, leaving it nothing more than a bit of senseless matter. If, however, the diamond (or turquoise) were offered as a pledge of love or friendship, the spirit was quite willing to transfer its good offices from one owner to another.

There were also health myths associated with turquoise. People believed the stone changed color when its wearer became ill. Some said it was an effective treatment for scorpion stings and pain from evil influences. Just looking at turquoise supposedly strengthen the eyes.

December birthstone: zircon

Several red zircon crystals embedded in a mostly quartz matrix. The entire piece measures about 2.1 cm (0.8 inches) in diameter. Image via Robert M. Lavinsky/ Wikimedia Commons (CC BY-SA 3.0).

Zircon is a mineral formed of the elements zirconium and silicon (zirconium silicate). Most igneous rocks contain small crystals, just a few millimeters in size. With a Mohs scale hardness of 7.5, zircon is hard enough to survive the geologic forces that create metamorphic and sedimentary rock. But large zircon crystals are rare. They’re formed mainly in pegmatites (coarse-grained igneous rock) and carbonatites. But due to weathering of gem-bearing rocks, most zircons are in alluvial and beach deposits.

The name zircon may have come from the Arabic words zarquin, meaning red. Or perhaps from the Persian word zargus, meaning gold-colored.

Major sources of gemstone-quality zircon are Thailand, Cambodia, Vietnam and Sri Lanka. The gemstones also occur in Myanmar, France, Norway, Australia and Canada.

Colors of zircon

Over vast spans of geologic time, forces have worked within zirconium silicate crystals to change their molecular structure and color. Uranium and thorium inclusions emit radiation that alters the original crystal structure. A glass-like material forms, with colors of red to brown, orange and yellow. Green is the rarest of the natural colors. Since the 1920s, most gemstones have undergone heat treatment to bring out their colors. This produces colorless zircons, as well as blue and golden stones.

Eight small round cut zircon gemstones. One is clear, three are different shades of red, and four are different shades of yellow.
Cut zircon stones from Vietnam. Image via Robert M. Lavinsky / Wikimedia Commons (CC BY-SA 3.0).

The creation of blue stones is in an interesting story relayed in “Gems and Crystals” by Anna S. Sofianides and George E. Harlow:

In the 1920s, a new blue gemstone suddenly appeared in the market. Endowed with spectacular brilliance, it was an immediate hit.

The creation of the blue zircon

The gems, it turned out, were zircons, normally brown to green, but never before blue. George F. Kunz, the legendary Tiffany gemologist, immediately suspected trickery; not only were there extraordinary stones available in abundance, but they were available all over the world! Upon Kunz’s behest, a colleague made inquiries during a trip to Siam (Thailand) and learned that a large deposit of unattractive brown zircon had stimulated color-improvement experimentation by local entrepreneurs. Heating in an oxygen-free environment made the drab material into “new” blue stones, which vendors sent to outlets worldwide. Even after finding out about the deception, the market simply accepted the information and the demand for the new gems continued unabated.

The blue stones are a clear favorite among zircon customers. Red and green colors are also valuable. Colorless zircons are excellent imitators of diamonds, in appearance only, with a brilliant fire almost as dazzling as the real thing. However, zircon can be brittle and cutting takes great care. It breaks with a well-placed knock, due to internal stresses in the crystal caused by radiation damage and heat treatment. But it remains in demand for its stunning beauty. In addition, other factors that affect pricing of the gemstones are clarity and an absence of visible inclusions.

Zircon lore

Green zircon was among the stones of the Kalpa Tree of the Hindu religion, where it represented the tree’s foliage. This tree was a symbolic offering to the gods. Hindu poets of the 19th century described it as part of a glowing ensemble of precious stones that also included sapphires, diamonds and topaz.

The hyacinth and jacinth, reddish-brown and orange-red varieties of zircon, were a favorite stone of ancient Arabs, even mentioned in the famed “Arabian Nights.”

During the 14th century, zircon was popular as a safeguard against the Black Death, the great plague that wiped out a quarter of the population of Europe. People believed the stone possessed healing powers: to induce sleep, as an antidote against poison, and as an aid to digestion.

A zircon shaped mostly like a rectangle except that the top is pointed. The entire crystal is olive-green.
A rare olive-green zircon, measuring about 3.4 cm (1.3 inches) in length, from Myanmar. Image via Robert M. Lavinsky/ Wikimedia Commons (CC BY-SA 3.0).

December birthstone: tanzanite

A rugged transparent light blue-violet rock with some transparent white regions.
A tanzanite crystal from the Merelani Hills, Arusha Region, Tanzania. Image via Parent Géry/ Wikimedia Commons (CC BY-SA 3.0).

Tanzanite is an unusual form of the mineral zoisite (calcium aluminium hydroxyl sorosilicate). Its colors, blue and violet, are due to the presence of vanadium in the zoisite crystals. This gemstone formed 585 million years ago under extreme heat during intense plate tectonic activity, in a place that would someday become Mount Kilimanjaro in northern Tanzania.

Today, you can only find tanzanite in the Merelani Hills near the foot of Mount Kilimanjaro.

Colors from different angles

In its natural form, tanzanite appears brown, yellowish green, blue and violet, flashing these colors when viewed from different angles. This phenomenon is pleochroism, where you can see different colors depending on how light hits the gemstone.

The type of lighting can also make a difference. Under fluorescent lights, tanzanite appears bluer, while under incandescent light, more violet hues emerge.

However, most crystals used in jewelry received doses of heat to remove the brownish color found in the natural tanzanite. The results are more intensely blue and violet gems. On rare occasions, heated stones can produce a green gem with secondary blue and violet colors. For cut gems, cutters can influence their overall color by how they craft the gem.

Tanzanite’s recent history

While most birthstones have histories spanning hundreds and even thousands of years, tanzanite’s story began in 1967. A Masai tribesman found unusual clear violet-blue crystals in the Merelani Hills in northern Tanzania. He notified a local tailor and prospector, Manuel d’Souza, who, upon finding the gemstones, filed the first of many mining claims.

Initially, d’Souza thought they were sapphires. But no one knew for sure. The stones made their way to geologists at the Gemological Institute of America where they identified them as an unusual form of zoisite.

And then, the famed jewelry purveyors, Tiffany & Company, took an interest in the gem. In 1968, they began a marketing campaign. To make the gems more appealing to buyers, they renamed blue zoisite to tanzanite, in honor of its country of origin. Finally, in 2002, the American Gem Trade Association selected tanzanite to join turquoise and zircon as December birthstones.

Beyond the December birthstone: birthstones for all months

January birthstone
February birthstone
March birthstone
April birthstone
May birthstone
June birthstone
July birthstone
August birthstone
September birthstone
October birthstone
November birthstone
December birthstone

Bottom line: December babies are fortunate enough to have three choices for their birthstone. Turquoise, zircon and tanzanite are the birthstones for December.

The post December birthstone: turquoise, zircon or tanzanite first appeared on EarthSky.



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Are Uranus and Neptune hiding oceans of water?

A dark sphere with cutaways of half spheres of different layers, dark, watery blue, icy white and cloudy.
Here’s a cutaway view of what an icy giant, such as Uranus and Neptune, might look like on the inside. There might be a layer of water on the planets (blue) separated from a layer rich in carbon. Image via Quanta Magazine/ UC Berkeley.
  • Uranus and Neptune are the ice giant planets in our solar system. They have deep atmospheres of hydrogen, helium and methane. But what are they like on the inside?
  • Scientists thought Uranus and Neptune contain an unusual form of water that is part liquid and part solid, as well as methane and ammonia. Intense pressures might also turn carbon atoms into diamond material that rains down in the planets’ atmospheres.
  • Instead, Uranus and Neptune might have deep oceans of water below their atmospheres, a new study suggests. Another layer rich in carbon would be below that, and the two layers can never mix together, like oil and water.

Are Uranus and Neptune water worlds?

Scientists have long thought that the ice giants – Uranus and Neptune – have a hot, dense fluid of icy water, methane and ammonia around their cores. But on November 25, 2024, scientists at the University of California, Berkeley, suggested a different scenario. Instead, they said the interiors of the two giant planets may be more layered, with deep global oceans of water beneath their atmospheres. This could also explain why both planets have unusually disorganized magnetic fields.

The researchers published their peer-reviewed findings in Proceedings of the National Academy of Sciences (PNAS) on November 25, 2024.

Looking for a good astronomy-related gift for Christmas? The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

The ice giants Uranus and Neptune

Uranus and Neptune are the two ice giants in our solar system. Unlike the gas giants Jupiter and Saturn, their interiors are thought to contain more icy water, methane and ammonia. The water may be in the form of superionic water, which is actually part solid and part liquid. This region is below the planets’ deep, thick atmospheres. Below that is a solid core.

Scientists have also theorized that their interiors contain superionic water ice, which is actually hot and part solid and part liquid. Or diamond rain, where pressures are so great that carbon atoms get squeezed into diamond and rain down in the atmosphere. Wild!

Uranus and Neptune: Greenish-blue planet and left and darker bluish planet on right, in black space. The darker planet has faint dark streaks and oval shape in its atmosphere, with bright clouds around the oval.
View larger. | NASA’s Voyager 2 spacecraft captured these views of Uranus and Neptune during its flybys of the planets in the late 1980s. A new study suggests both giant planets could have deep layers of water below their atmospheres. Image via NASA/ JPL-Caltech/ B. Jónsson/ NOIRLab.

A layered interior with oceans?

But now, researcher Burkhard Militzer at UC Berkeley has proposed an alternative possibility. The interiors of both planets may be more distinctly layered. In this scenario, a global ocean of water is below each planet’s atmosphere. And below that would be a highly compressed fluid of carbon, nitrogen and hydrogen.

But just like oil and water, the two layers don’t mix and remain separate.

Previous studies have suggested the interiors of both planets contain icy water, methane and ammonia. The new study suggests that instead of remaining as one layer, this region divided into the two distinct layers. Essentially, hydrogen would be squeezed out of the methane and ammonia.

The study estimates that the water/ocean layer on both Uranus and Neptune is about 5,000 miles (8,000 km) thick. The carbon layer would be a similar thickness.

2 triangular cutaway diagrams with light blue, darker blue, red and yellow layers in them them. Each layer has a black text label. Other black text says Uranus and Neptune.
View larger. | Diagram depicting the interiors of Uranus and Neptune, based on the new model. The light blue on top is the thick atmosphere and the darker blue is the water-hydrogen ocean. Image via Burkhard Militzer/ UC Berkeley.

Lack of magnetic fields

Scientists have also long known that both Uranus and Neptune lack magnetic fields similar to Earth’s. The new study could explain why. Militzer said:

We now have, I would say, a good theory why Uranus and Neptune have really different fields, and it’s very different from Earth, Jupiter and Saturn. We didn’t know this before. It’s like oil and water, except the oil goes below because hydrogen is lost.

Voyager 2 found that both planets lack a dipole magnetic field, and instead only have disorganized magnetic fields. A dipole magnetic field is like what you see with a bar magnet. Earth’s dipole magnetic field is created by convection – the movement of heat through a fluid like air or water – in its interior, in the liquid outer iron core.

But since neither Uranus or Neptune have a dipole magnetic field, that means there’s no convection in their interiors. If there are two layers that don’t mix, that would prevent convection from occurring.

Simulating the planets’ interiors

Previously, Militzer used computer simulations of 100 atoms to try to figure out why the layers wouldn’t mix. The atoms had the same proportions of carbon, oxygen, nitrogen and hydrogen as the known composition of elements in the early solar system. The interiors of the two planets had an estimated 3.4 million times Earth’s atmospheric pressure and were 4,750 Kelvin (8,000°F) in temperature. But even in those simulations, he couldn’t determine what the layers would be composed of.

Then, last year, Militzer ran new simulations, but this time with 540 atoms. He found that in similar conditions in the interiors of Uranus and Neptune, the layers formed naturally. Militzer explained:

One day, I looked at the model, and the water had separated from the carbon and nitrogen. What I couldn’t do 10 years ago was now happening. I thought, ‘Wow! Now I know why the layers form: One is water-rich and the other is carbon-rich, and in Uranus and Neptune, it’s the carbon-rich system that is below. The heavy part stays in the bottom, and the lighter part stays on top and it cannot do any convecting.’

I couldn’t discover this without having a large system of atoms, and the large system I couldn’t simulate 10 years ago.

Water on top, carbon on bottom

So basically, it was like the oil and water analogy. Except in this case, the water layer stayed on top instead of the bottom. Convection could occur in the upper water-hydrogen ocean layer, but not in the lower carbon-rich layer. Therefore, the water layer could produce the disorganized magnetic field, but not a full dipole magnetic field like Earth.

In addition, the gravity fields of Uranus and Neptune in the layered model matches what Voyager 2 actually measured decades ago.

The new model could explain the interior behavior of both Uranus and Neptune without the need for diamond rain or superionic water. As Militzer said:

If you ask my colleagues, ‘What do you think explains the fields of Uranus and Neptune?’ they may say, ‘Well, maybe it’s this diamond rain, but maybe it’s this water property which we call superionic.’ From my perspective, this is not plausible. But if we have this separation into two separate layers, that should explain it.

Similarities to mini-Neptunes

The findings are reminiscent of some mini-Neptune type exoplanets, which are also thought to have deep water layers beneath thick hydrogen atmospheres. Others – called hycean worlds – might have solid surfaces, with deep global oceans and thick hydrogen atmospheres.

Bottom line: Uranus and Neptune might have deep water oceans beneath their thick atmospheres, with a carbon layer below them. Like oil and water, the two layers never mix.

Source: Phase separation of planetary ices explains nondipolar magnetic fields of Uranus and Neptune

Via University of Berkeley

Read more: True colors of Uranus and Neptune in newly processed images

Read more: New Hubble images show storms on Uranus and Neptune

The post Are Uranus and Neptune hiding oceans of water? first appeared on EarthSky.



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A dark sphere with cutaways of half spheres of different layers, dark, watery blue, icy white and cloudy.
Here’s a cutaway view of what an icy giant, such as Uranus and Neptune, might look like on the inside. There might be a layer of water on the planets (blue) separated from a layer rich in carbon. Image via Quanta Magazine/ UC Berkeley.
  • Uranus and Neptune are the ice giant planets in our solar system. They have deep atmospheres of hydrogen, helium and methane. But what are they like on the inside?
  • Scientists thought Uranus and Neptune contain an unusual form of water that is part liquid and part solid, as well as methane and ammonia. Intense pressures might also turn carbon atoms into diamond material that rains down in the planets’ atmospheres.
  • Instead, Uranus and Neptune might have deep oceans of water below their atmospheres, a new study suggests. Another layer rich in carbon would be below that, and the two layers can never mix together, like oil and water.

Are Uranus and Neptune water worlds?

Scientists have long thought that the ice giants – Uranus and Neptune – have a hot, dense fluid of icy water, methane and ammonia around their cores. But on November 25, 2024, scientists at the University of California, Berkeley, suggested a different scenario. Instead, they said the interiors of the two giant planets may be more layered, with deep global oceans of water beneath their atmospheres. This could also explain why both planets have unusually disorganized magnetic fields.

The researchers published their peer-reviewed findings in Proceedings of the National Academy of Sciences (PNAS) on November 25, 2024.

Looking for a good astronomy-related gift for Christmas? The 2025 EarthSky Lunar Calendar is now available! A unique and beautiful poster-sized calendar. Keep up with all phases of the moon every night of the year. Get yours today!

The ice giants Uranus and Neptune

Uranus and Neptune are the two ice giants in our solar system. Unlike the gas giants Jupiter and Saturn, their interiors are thought to contain more icy water, methane and ammonia. The water may be in the form of superionic water, which is actually part solid and part liquid. This region is below the planets’ deep, thick atmospheres. Below that is a solid core.

Scientists have also theorized that their interiors contain superionic water ice, which is actually hot and part solid and part liquid. Or diamond rain, where pressures are so great that carbon atoms get squeezed into diamond and rain down in the atmosphere. Wild!

Uranus and Neptune: Greenish-blue planet and left and darker bluish planet on right, in black space. The darker planet has faint dark streaks and oval shape in its atmosphere, with bright clouds around the oval.
View larger. | NASA’s Voyager 2 spacecraft captured these views of Uranus and Neptune during its flybys of the planets in the late 1980s. A new study suggests both giant planets could have deep layers of water below their atmospheres. Image via NASA/ JPL-Caltech/ B. Jónsson/ NOIRLab.

A layered interior with oceans?

But now, researcher Burkhard Militzer at UC Berkeley has proposed an alternative possibility. The interiors of both planets may be more distinctly layered. In this scenario, a global ocean of water is below each planet’s atmosphere. And below that would be a highly compressed fluid of carbon, nitrogen and hydrogen.

But just like oil and water, the two layers don’t mix and remain separate.

Previous studies have suggested the interiors of both planets contain icy water, methane and ammonia. The new study suggests that instead of remaining as one layer, this region divided into the two distinct layers. Essentially, hydrogen would be squeezed out of the methane and ammonia.

The study estimates that the water/ocean layer on both Uranus and Neptune is about 5,000 miles (8,000 km) thick. The carbon layer would be a similar thickness.

2 triangular cutaway diagrams with light blue, darker blue, red and yellow layers in them them. Each layer has a black text label. Other black text says Uranus and Neptune.
View larger. | Diagram depicting the interiors of Uranus and Neptune, based on the new model. The light blue on top is the thick atmosphere and the darker blue is the water-hydrogen ocean. Image via Burkhard Militzer/ UC Berkeley.

Lack of magnetic fields

Scientists have also long known that both Uranus and Neptune lack magnetic fields similar to Earth’s. The new study could explain why. Militzer said:

We now have, I would say, a good theory why Uranus and Neptune have really different fields, and it’s very different from Earth, Jupiter and Saturn. We didn’t know this before. It’s like oil and water, except the oil goes below because hydrogen is lost.

Voyager 2 found that both planets lack a dipole magnetic field, and instead only have disorganized magnetic fields. A dipole magnetic field is like what you see with a bar magnet. Earth’s dipole magnetic field is created by convection – the movement of heat through a fluid like air or water – in its interior, in the liquid outer iron core.

But since neither Uranus or Neptune have a dipole magnetic field, that means there’s no convection in their interiors. If there are two layers that don’t mix, that would prevent convection from occurring.

Simulating the planets’ interiors

Previously, Militzer used computer simulations of 100 atoms to try to figure out why the layers wouldn’t mix. The atoms had the same proportions of carbon, oxygen, nitrogen and hydrogen as the known composition of elements in the early solar system. The interiors of the two planets had an estimated 3.4 million times Earth’s atmospheric pressure and were 4,750 Kelvin (8,000°F) in temperature. But even in those simulations, he couldn’t determine what the layers would be composed of.

Then, last year, Militzer ran new simulations, but this time with 540 atoms. He found that in similar conditions in the interiors of Uranus and Neptune, the layers formed naturally. Militzer explained:

One day, I looked at the model, and the water had separated from the carbon and nitrogen. What I couldn’t do 10 years ago was now happening. I thought, ‘Wow! Now I know why the layers form: One is water-rich and the other is carbon-rich, and in Uranus and Neptune, it’s the carbon-rich system that is below. The heavy part stays in the bottom, and the lighter part stays on top and it cannot do any convecting.’

I couldn’t discover this without having a large system of atoms, and the large system I couldn’t simulate 10 years ago.

Water on top, carbon on bottom

So basically, it was like the oil and water analogy. Except in this case, the water layer stayed on top instead of the bottom. Convection could occur in the upper water-hydrogen ocean layer, but not in the lower carbon-rich layer. Therefore, the water layer could produce the disorganized magnetic field, but not a full dipole magnetic field like Earth.

In addition, the gravity fields of Uranus and Neptune in the layered model matches what Voyager 2 actually measured decades ago.

The new model could explain the interior behavior of both Uranus and Neptune without the need for diamond rain or superionic water. As Militzer said:

If you ask my colleagues, ‘What do you think explains the fields of Uranus and Neptune?’ they may say, ‘Well, maybe it’s this diamond rain, but maybe it’s this water property which we call superionic.’ From my perspective, this is not plausible. But if we have this separation into two separate layers, that should explain it.

Similarities to mini-Neptunes

The findings are reminiscent of some mini-Neptune type exoplanets, which are also thought to have deep water layers beneath thick hydrogen atmospheres. Others – called hycean worlds – might have solid surfaces, with deep global oceans and thick hydrogen atmospheres.

Bottom line: Uranus and Neptune might have deep water oceans beneath their thick atmospheres, with a carbon layer below them. Like oil and water, the two layers never mix.

Source: Phase separation of planetary ices explains nondipolar magnetic fields of Uranus and Neptune

Via University of Berkeley

Read more: True colors of Uranus and Neptune in newly processed images

Read more: New Hubble images show storms on Uranus and Neptune

The post Are Uranus and Neptune hiding oceans of water? first appeared on EarthSky.



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Thanksgiving turkey: White meat or dark meat?

Thanksgiving turkey: Four birds with feathers on their bodies. Two are white, one is brown and the other is black. The heads look red and don't have feathers.
Thanksgiving turkey raises an important question: White or dark meat? White meat lovers claim dark meat is greasy; dark meat devotees complain that white meat is dry and lacks flavor. Image via Mikkel Bergmann/ Unsplash.

By Joshua Selsby, Iowa State University

White meat or dark meat?

As families gather together this holiday season, the lucky ones will avoid impassioned discussions about religion and politics. But another argument is almost inevitable: white meat versus dark meat.

White meat lovers claim dark meat is greasy; dark meat devotees complain that white meat is dry and lacks flavor. Few meat eaters are ambivalent on the matter.

But why do these different types of meat exist, and what underlies these differences? As a muscle physiologist, I can tell you it comes down to the metabolic and functional differences between various types of muscle.

Consider how turkeys move. Have you ever seen a flock of turkeys fly by? Of course not! If a turkey is threatened, it can take flight for brief periods in an attempt to escape. But these birds spend most of their time standing and walking.

These activities – walking and standing versus brief, panicked flight – are quite different. They’re supported by different kinds of muscles geared to these different functions, and you can see those differences on your dinner plate.

The 2025 EarthSky lunar calendar makes a great gift. Get yours today!

Bird with abundant plumage that is black and white. It has a featherless red head.
The different types of meat come down to the metabolic and functional differences between various types of muscle. Image via Caroline Quiering/ Unsplash.

What makes dark meat dark?

Consider first the dark meat, which is found largely in the legs. This type of meat comes from muscles that get lots of use as turkeys spend their time walking around being turkeys.

Muscle physiologists call these sorts of muscles slow twitch or type I muscles. They are also called oxidative muscles, which refers to how they produce adenosine triphosphate, abbreviated as ATP. Think of ATP as a cell’s energy currency for performing a given function. Cells don’t need a job to earn this cash; they simply produce it.

The muscles’ metabolism must be able to support them throughout their long, sustained activities. In this case, because lots of ATP must be produced over extended periods of time, the muscle cells rely on their organelles called mitochondria. The mitochondria are like factories that manufacture ATP.

It’s the mitochondria that lend dark meat one of its distinguishing characteristics. They can use fat to produce ATP. Because of its higher muscle fat content, some people may perceive dark muscle as greasy, while others deem it delicious.

Mitochondria also require oxygen in order to function. They rely on an iron-containing protein called myoglobin, which shuttles oxygen from the blood to the mitochondria found inside muscle. Because of the large amount of myoglobin, these muscles appear dark.

A cooked turkey leg, with a slice off, on a plate with potatoes.
Deliciously dark or grotesquely greasy? Image via Andrii Ridnyi/ Shutterstock.com.

What makes white meat light?

What about that drier, white meat? Again, it’s useful to first consider its function.

White meat is found largely in the breast muscles, which are used to create the explosive force needed for flight. But keep in mind that for turkeys, this flight is very short in duration: just long enough to escape a predator. This job is ideally suited for what physiologists call type II or fast twitch muscle.

This sort of activity is supported by a different means of ATP production – one that does not heavily rely on mitochondria or require oxygen. White muscles use a process called glycolysis, which requires carbohydrates to create ATP. They are light in color because of their low capacity to use oxygen during exercise; there is simply no need for a high abundance of the iron-rich oxygen shuttle, myoglobin.

White muscles have a low fat content because they don’t need and don’t have a large amount of mitochondria required to make ATP from fat. That’s why some people find this meat to be dry.

Cooked turkey. Slices of white meat.
Lusciously lean or depressingly dry? Image via Paul Cowan/ Shutterstock.com.

It is all about muscles

Different species of animals perform different jobs with their muscles. For instance, duck breast muscles must support very long duration flights, and like turkey legs, are dark in color and loaded with fat.

In case you’re wondering, people’s muscles are a bit more complicated than just white or dark. Most human muscles are what physiologists consider mixed, with a variety of oxidative and slow muscle fibers. People with proportionally more of one than another might excel at different activities – think sprinters versus marathon runners.

Next time you sit down to enjoy your holiday meal, have confidence that you know why your meat choice tastes delicious.

Joshua Selsby, Professor of Animal Science, Iowa State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Thanksgiving turkey raises an important question: Dark or white meat? Amaze your companions on why different cuts of turkey have different characteristics.

Vultures are the best clean-up crew: Lifeform of the week

Flamingos are beautiful and peculiar: Lifeform of the week

The Conversation

The post Thanksgiving turkey: White meat or dark meat? first appeared on EarthSky.



from EarthSky https://ift.tt/mfHd6xR
Thanksgiving turkey: Four birds with feathers on their bodies. Two are white, one is brown and the other is black. The heads look red and don't have feathers.
Thanksgiving turkey raises an important question: White or dark meat? White meat lovers claim dark meat is greasy; dark meat devotees complain that white meat is dry and lacks flavor. Image via Mikkel Bergmann/ Unsplash.

By Joshua Selsby, Iowa State University

White meat or dark meat?

As families gather together this holiday season, the lucky ones will avoid impassioned discussions about religion and politics. But another argument is almost inevitable: white meat versus dark meat.

White meat lovers claim dark meat is greasy; dark meat devotees complain that white meat is dry and lacks flavor. Few meat eaters are ambivalent on the matter.

But why do these different types of meat exist, and what underlies these differences? As a muscle physiologist, I can tell you it comes down to the metabolic and functional differences between various types of muscle.

Consider how turkeys move. Have you ever seen a flock of turkeys fly by? Of course not! If a turkey is threatened, it can take flight for brief periods in an attempt to escape. But these birds spend most of their time standing and walking.

These activities – walking and standing versus brief, panicked flight – are quite different. They’re supported by different kinds of muscles geared to these different functions, and you can see those differences on your dinner plate.

The 2025 EarthSky lunar calendar makes a great gift. Get yours today!

Bird with abundant plumage that is black and white. It has a featherless red head.
The different types of meat come down to the metabolic and functional differences between various types of muscle. Image via Caroline Quiering/ Unsplash.

What makes dark meat dark?

Consider first the dark meat, which is found largely in the legs. This type of meat comes from muscles that get lots of use as turkeys spend their time walking around being turkeys.

Muscle physiologists call these sorts of muscles slow twitch or type I muscles. They are also called oxidative muscles, which refers to how they produce adenosine triphosphate, abbreviated as ATP. Think of ATP as a cell’s energy currency for performing a given function. Cells don’t need a job to earn this cash; they simply produce it.

The muscles’ metabolism must be able to support them throughout their long, sustained activities. In this case, because lots of ATP must be produced over extended periods of time, the muscle cells rely on their organelles called mitochondria. The mitochondria are like factories that manufacture ATP.

It’s the mitochondria that lend dark meat one of its distinguishing characteristics. They can use fat to produce ATP. Because of its higher muscle fat content, some people may perceive dark muscle as greasy, while others deem it delicious.

Mitochondria also require oxygen in order to function. They rely on an iron-containing protein called myoglobin, which shuttles oxygen from the blood to the mitochondria found inside muscle. Because of the large amount of myoglobin, these muscles appear dark.

A cooked turkey leg, with a slice off, on a plate with potatoes.
Deliciously dark or grotesquely greasy? Image via Andrii Ridnyi/ Shutterstock.com.

What makes white meat light?

What about that drier, white meat? Again, it’s useful to first consider its function.

White meat is found largely in the breast muscles, which are used to create the explosive force needed for flight. But keep in mind that for turkeys, this flight is very short in duration: just long enough to escape a predator. This job is ideally suited for what physiologists call type II or fast twitch muscle.

This sort of activity is supported by a different means of ATP production – one that does not heavily rely on mitochondria or require oxygen. White muscles use a process called glycolysis, which requires carbohydrates to create ATP. They are light in color because of their low capacity to use oxygen during exercise; there is simply no need for a high abundance of the iron-rich oxygen shuttle, myoglobin.

White muscles have a low fat content because they don’t need and don’t have a large amount of mitochondria required to make ATP from fat. That’s why some people find this meat to be dry.

Cooked turkey. Slices of white meat.
Lusciously lean or depressingly dry? Image via Paul Cowan/ Shutterstock.com.

It is all about muscles

Different species of animals perform different jobs with their muscles. For instance, duck breast muscles must support very long duration flights, and like turkey legs, are dark in color and loaded with fat.

In case you’re wondering, people’s muscles are a bit more complicated than just white or dark. Most human muscles are what physiologists consider mixed, with a variety of oxidative and slow muscle fibers. People with proportionally more of one than another might excel at different activities – think sprinters versus marathon runners.

Next time you sit down to enjoy your holiday meal, have confidence that you know why your meat choice tastes delicious.

Joshua Selsby, Professor of Animal Science, Iowa State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Bottom line: Thanksgiving turkey raises an important question: Dark or white meat? Amaze your companions on why different cuts of turkey have different characteristics.

Vultures are the best clean-up crew: Lifeform of the week

Flamingos are beautiful and peculiar: Lifeform of the week

The Conversation

The post Thanksgiving turkey: White meat or dark meat? first appeared on EarthSky.



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