Scientists uncovered the diets of two pterosaur species found in Germany from fossilized stomach contents.
Dorygnathus banthensis mainly ate small fish, while Campylognathoides zitteli consumed squid, showing they had different diets.
The fossilized stomach contents offer valuable information about the feeding habits and ecosystems of pterosaurs in the Jurassic period.
What did pterosaurs eat?
Pterosaurs were winged reptiles that dominated the skies during the age of the dinosaurs. Historically, scientists knew little about the diet and feeding strategies of these creatures. On October 23, 2024, a group of researchers said they’ve examined two pterosaur specimens in great detail. Remarkably, they were able to find fossilized stomach contents. Moreover, they were even able to identify the prey consumed by the pterosaurs.
The scientists published their findings in the peer-reviewedJournal of Vertebrate Paleontology on October 23, 2024.
A look at pterosaur fossil number one
The researchers conducted a detailed study of two previously collected fossilized pterosaur species. The 182-million-year-old specimens came from a shale formation at Baden-Württemberg in southwest Germany.
They found one of the fossilized remains – belonging to the species Dorygnathus banthensis – had eaten small fish (from the genus Leptolepis) shortly before it died. Consequently, there was little time for the stomach acids to break down the fish bones. Thus, the bones of the food were also preserved in the fossil.
Pterosaur fossil number two
The other pterosaur species they examined was Campylognathoides zitteli. In this case, the stomach contents examination revealed the animal had consumed squid shortly before its death. The scientists knew it was squid because tiny hooks, attached to tentacles to grab prey, survived in fossilized form. Furthermore, based on the hooks, they could identify the squid species: Clarkeiteuthis conocauda. Thus, this discovery suggests that Campylognathoides may have been a nocturnal hunter, because squid travel to the sea surface at night.
Fossilized stomach contents are extremely rare
These pterosaurs, like modern-day seabirds, spent much of their time flying in search of prey. They once soared over the warm tropical seas that covered south Germany during the Jurassic Period. In order to stay aloft for long periods, they had to digest their food quickly to reduce the weight in their stomaches. Therefore, it’s rare to find fossilized stomach contents in pterosaurs.
David Martill, from the University of Portsmouth, a co-author of the paper, said:
It is incredibly rare to find 180-million-year-old pterosaurs preserved with their stomach contents, and provides “smoking gun” evidence for pterosaur diets. The discovery offers a unique and fascinating glimpse into how these ancient creatures lived, what they ate, and the ecosystems they thrived in millions of years ago.
What these results tell us about the pterosaurs’ world
The scientists discovered two different pterosaur species, which existed at the same time, but appear to have had different diets. Samuel Cooper of the State Museum of Natural History Stuttgart, the lead author of the paper, said:
The fossilized stomach contents tell us a lot about the ecosystem at that time and how the animals interacted with each other. For me, this evidence of squid remains in the stomach of Campylognathoides is therefore particularly exciting. Until now, we tended to assume that it fed on fish, similar to Dorygnathus, in which we found small fish bones as stomach contents. The fact that these two pterosaur species ate different prey shows that they were likely specialized for different diets. This allowed Dorygnathus and Campylognathoides to coexist in the same habitat without much competition for food between the two species.
The pterosaurs were found in a unique fossil site
The geologic formation that held the fossilized remains of the two pterosaurs provides more insight into their aquatic world. It’s called the Posidonia Shale. This is a black shale formation, dated at 182 million years old. A part of this formation, where scientists found the two pterosaurs, lies in southwest Germany.
This region was once a muddy seabed. There, animals quickly sank into the soft mud before scavengers could get to them or sea currents could disturb their remains. And low oxygen levels kept the remains in good condition for fossilization.
The site is notable for its diverse and well-preserved fossilized marine fauna. Scientists have found remarkable specimens there, including a pregnant ichthyosaur with fossilized embryos, plesiosaurs, marine crocodiles, several large fish species, crustaceans, cuttlefish, ammonites and more pterosaurs.
Bottom line: Fossilized stomach contents of two well-preserved pterosaur species from southwestern Germany offered valuable information about the feeding habits and ecosystems of pterosaurs in the Jurassic period.
Scientists uncovered the diets of two pterosaur species found in Germany from fossilized stomach contents.
Dorygnathus banthensis mainly ate small fish, while Campylognathoides zitteli consumed squid, showing they had different diets.
The fossilized stomach contents offer valuable information about the feeding habits and ecosystems of pterosaurs in the Jurassic period.
What did pterosaurs eat?
Pterosaurs were winged reptiles that dominated the skies during the age of the dinosaurs. Historically, scientists knew little about the diet and feeding strategies of these creatures. On October 23, 2024, a group of researchers said they’ve examined two pterosaur specimens in great detail. Remarkably, they were able to find fossilized stomach contents. Moreover, they were even able to identify the prey consumed by the pterosaurs.
The scientists published their findings in the peer-reviewedJournal of Vertebrate Paleontology on October 23, 2024.
A look at pterosaur fossil number one
The researchers conducted a detailed study of two previously collected fossilized pterosaur species. The 182-million-year-old specimens came from a shale formation at Baden-Württemberg in southwest Germany.
They found one of the fossilized remains – belonging to the species Dorygnathus banthensis – had eaten small fish (from the genus Leptolepis) shortly before it died. Consequently, there was little time for the stomach acids to break down the fish bones. Thus, the bones of the food were also preserved in the fossil.
Pterosaur fossil number two
The other pterosaur species they examined was Campylognathoides zitteli. In this case, the stomach contents examination revealed the animal had consumed squid shortly before its death. The scientists knew it was squid because tiny hooks, attached to tentacles to grab prey, survived in fossilized form. Furthermore, based on the hooks, they could identify the squid species: Clarkeiteuthis conocauda. Thus, this discovery suggests that Campylognathoides may have been a nocturnal hunter, because squid travel to the sea surface at night.
Fossilized stomach contents are extremely rare
These pterosaurs, like modern-day seabirds, spent much of their time flying in search of prey. They once soared over the warm tropical seas that covered south Germany during the Jurassic Period. In order to stay aloft for long periods, they had to digest their food quickly to reduce the weight in their stomaches. Therefore, it’s rare to find fossilized stomach contents in pterosaurs.
David Martill, from the University of Portsmouth, a co-author of the paper, said:
It is incredibly rare to find 180-million-year-old pterosaurs preserved with their stomach contents, and provides “smoking gun” evidence for pterosaur diets. The discovery offers a unique and fascinating glimpse into how these ancient creatures lived, what they ate, and the ecosystems they thrived in millions of years ago.
What these results tell us about the pterosaurs’ world
The scientists discovered two different pterosaur species, which existed at the same time, but appear to have had different diets. Samuel Cooper of the State Museum of Natural History Stuttgart, the lead author of the paper, said:
The fossilized stomach contents tell us a lot about the ecosystem at that time and how the animals interacted with each other. For me, this evidence of squid remains in the stomach of Campylognathoides is therefore particularly exciting. Until now, we tended to assume that it fed on fish, similar to Dorygnathus, in which we found small fish bones as stomach contents. The fact that these two pterosaur species ate different prey shows that they were likely specialized for different diets. This allowed Dorygnathus and Campylognathoides to coexist in the same habitat without much competition for food between the two species.
The pterosaurs were found in a unique fossil site
The geologic formation that held the fossilized remains of the two pterosaurs provides more insight into their aquatic world. It’s called the Posidonia Shale. This is a black shale formation, dated at 182 million years old. A part of this formation, where scientists found the two pterosaurs, lies in southwest Germany.
This region was once a muddy seabed. There, animals quickly sank into the soft mud before scavengers could get to them or sea currents could disturb their remains. And low oxygen levels kept the remains in good condition for fossilization.
The site is notable for its diverse and well-preserved fossilized marine fauna. Scientists have found remarkable specimens there, including a pregnant ichthyosaur with fossilized embryos, plesiosaurs, marine crocodiles, several large fish species, crustaceans, cuttlefish, ammonites and more pterosaurs.
Bottom line: Fossilized stomach contents of two well-preserved pterosaur species from southwestern Germany offered valuable information about the feeding habits and ecosystems of pterosaurs in the Jurassic period.
Five huge satellites – each blocking an area of the sky about the size of two city buses – unfurled their giant antennae in low Earth orbit this week. The spacecrafts’ enormous surface areas are expected to make them shine at up to magnitude 0.4. That’s brighter than nine of the 10 brightest stars.
AST SpaceMobile announced the craft – BlueBirds 1-5 – successfully unfolded their 639-square-foot (64-square-meter) antennae on Friday, October 25, 2024. Company founder and CEO Abel Avellan said plans to place 100 or more of the craft in space is quickly moving ahead:
These five satellites are the largest commercial communications arrays ever launched in low Earth orbit. It is a significant achievement to commission these satellites, and we are now accelerating our path to commercial activity.
The company says its satellites will benefit regions with little or no cellular telephone coverage. But the International Astronomical Union (IAU) believes the plan will further degrade the night sky.
Made in TX — size matters! #BlueWalker3's 693 sq ft array would be largest-ever commercial comms array in LEO. We're building the first & only cellular broadband network in space backed by 2,400 patent and patent-pending claims. Removing before-flight tags today!!! ???? #5G?? pic.twitter.com/Vx4oNVNYCK
BlueBird causes concern among professional astronomers
A peer-reviewed paper published in Nature in October of 2023 confirmed the astronomical community’s fears. The study tracked the brightness of BlueWalker 3, the prototype for the BlueBird, which matches it in size.
The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky.
BlueWalker 3 grew and dimmed in brightness. At its weakest, it shone at magnitude 6, the limit of human vision. But it retuned to its brightest level, especially when it passed high overhead. At magnitude 0.4, BlueBird will be visible in even the most light-polluted locations.
The BlueBird constellation could also pose a threat to radio astronomy. Broadcast frequencies used by AST SpaceMobile are of particular concern, the IAU said:
Frequencies allocated to cell phones are already challenging to observe even in radio quiet zones we have created for our facilities. New satellites such as BlueWalker 3 have the potential to worsen this situation and compromise our ability to do science if not properly mitigated.
The IAU also acknowledged the need for satellite constellations … as well as caution. And BlueBird will provide what appears to be a worthwhile service, according to the company’s marketing department:
Our engineers and space scientists are on a mission to eliminate the connectivity gaps faced by today’s five billion mobile subscribers and finally bring broadband to the billions who remain unconnected.
BlueBird constellation highlights crowding of low Earth orbit
AST SpaceMobile is far from the only company filling low Earth orbit with hundreds of new satellites. Or more. Projects such as SpaceX’s Starlink plan to fly tens of thousands of satellites. This rapid growth is raising the specter of catastrophic runaway satellite collisions, even outside the spaceflight community. The venerable publication Popular Science addressed the danger in its coverage of BlueBird:
In these scenarios, the untenable amount of human-made objects leads to ever-increasing collisions, causing debris to deorbit and pose a danger to anything in its path.
Experts have long feared this scenario, known as the Kessler syndrome. EarthSky reported on the danger in March 2024 after space junk from the ISS struck Earth:
As early as 1978, NASA scientist Donald Kessler was pondering what would happen as more satellites took up residence in orbit around Earth. Now known as the Kessler syndrome, the scenario imagines the density of objects in low-Earth orbit becoming high enough that it creates a cascade of collisions, with each collision generating space debris that increases the likelihood of further collisions.
Because of their large size, the AST SpaceMobile BlueBird constellation may be particularly at risk of collision.
Bottom line: BlueBird, the largest communications satellites ever, opened their antennae this week. Astronomers believe the bright craft will further degrade the night sky.
Five huge satellites – each blocking an area of the sky about the size of two city buses – unfurled their giant antennae in low Earth orbit this week. The spacecrafts’ enormous surface areas are expected to make them shine at up to magnitude 0.4. That’s brighter than nine of the 10 brightest stars.
AST SpaceMobile announced the craft – BlueBirds 1-5 – successfully unfolded their 639-square-foot (64-square-meter) antennae on Friday, October 25, 2024. Company founder and CEO Abel Avellan said plans to place 100 or more of the craft in space is quickly moving ahead:
These five satellites are the largest commercial communications arrays ever launched in low Earth orbit. It is a significant achievement to commission these satellites, and we are now accelerating our path to commercial activity.
The company says its satellites will benefit regions with little or no cellular telephone coverage. But the International Astronomical Union (IAU) believes the plan will further degrade the night sky.
Made in TX — size matters! #BlueWalker3's 693 sq ft array would be largest-ever commercial comms array in LEO. We're building the first & only cellular broadband network in space backed by 2,400 patent and patent-pending claims. Removing before-flight tags today!!! ???? #5G?? pic.twitter.com/Vx4oNVNYCK
BlueBird causes concern among professional astronomers
A peer-reviewed paper published in Nature in October of 2023 confirmed the astronomical community’s fears. The study tracked the brightness of BlueWalker 3, the prototype for the BlueBird, which matches it in size.
The peak brightness of the satellite reached an apparent magnitude of 0.4. This made the new satellite one of the brightest objects in the night sky.
BlueWalker 3 grew and dimmed in brightness. At its weakest, it shone at magnitude 6, the limit of human vision. But it retuned to its brightest level, especially when it passed high overhead. At magnitude 0.4, BlueBird will be visible in even the most light-polluted locations.
The BlueBird constellation could also pose a threat to radio astronomy. Broadcast frequencies used by AST SpaceMobile are of particular concern, the IAU said:
Frequencies allocated to cell phones are already challenging to observe even in radio quiet zones we have created for our facilities. New satellites such as BlueWalker 3 have the potential to worsen this situation and compromise our ability to do science if not properly mitigated.
The IAU also acknowledged the need for satellite constellations … as well as caution. And BlueBird will provide what appears to be a worthwhile service, according to the company’s marketing department:
Our engineers and space scientists are on a mission to eliminate the connectivity gaps faced by today’s five billion mobile subscribers and finally bring broadband to the billions who remain unconnected.
BlueBird constellation highlights crowding of low Earth orbit
AST SpaceMobile is far from the only company filling low Earth orbit with hundreds of new satellites. Or more. Projects such as SpaceX’s Starlink plan to fly tens of thousands of satellites. This rapid growth is raising the specter of catastrophic runaway satellite collisions, even outside the spaceflight community. The venerable publication Popular Science addressed the danger in its coverage of BlueBird:
In these scenarios, the untenable amount of human-made objects leads to ever-increasing collisions, causing debris to deorbit and pose a danger to anything in its path.
Experts have long feared this scenario, known as the Kessler syndrome. EarthSky reported on the danger in March 2024 after space junk from the ISS struck Earth:
As early as 1978, NASA scientist Donald Kessler was pondering what would happen as more satellites took up residence in orbit around Earth. Now known as the Kessler syndrome, the scenario imagines the density of objects in low-Earth orbit becoming high enough that it creates a cascade of collisions, with each collision generating space debris that increases the likelihood of further collisions.
Because of their large size, the AST SpaceMobile BlueBird constellation may be particularly at risk of collision.
Bottom line: BlueBird, the largest communications satellites ever, opened their antennae this week. Astronomers believe the bright craft will further degrade the night sky.
Uranus is the sixth planet from the sun in our solar system, orbiting some 19 times farther away from the sun than Earth does. One of its moons, Miranda, is 1/7 the size of our moon and has a crazy-quilt surface of scarps and craters. On October 28, 2024, researchers from Johns Hopkins University said they’ve modeled how the interior structure of the moon could create the bizarre surface patterns. The model with the best fit required the existence of a vast ocean beneath Miranda’s ice some 100 to 500 million years ago. Co-author Tom Nordheim of Johns Hopkins said:
To find evidence of an ocean inside a small object like Miranda is incredibly surprising. It helps build on the story that some of these moons at Uranus may be really interesting … that there may be several ocean worlds around one of the most distant planets in our solar system, which is both exciting and bizarre.
The researchers published their peer-reviewed findings in The Planetary Science Journal on October 15, 2024.
Evidence for an ocean
The only part of Miranda we’ve seen is its southern hemisphere. Scientists believe its grooved terrain (pockmarked with craters) is a result of heating from the moon’s internal tidal forces. The team of scientists took another look at the Voyager 2 images and decided to try to work backward:
to uncover what the moon’s interior structure must have been to shape the moon’s geology in response to tidal forcing.
Lead author Caleb Strom, a graduate student at the University of North Dakota, worked with scientists from the Planetary Science Institute in Arizona. They mapped Miranda’s surface features and then used computer models to match the stress patterns to the moon.
What they found was the best match required a vast ocean under Miranda’s surface. The ocean would have to be no more than 19 miles (30 km) beneath the moon’s crust of ice. And the ocean itself would have to be at least 62 miles (100 km) deep. The little moon is only 292 miles (470 km) across. So the ocean would take up a big chunk of the moon’s interior. Strom said:
That result was a big surprise to the team.
A thin ocean might remain under ice on Uranus’s moon
Uranus has 28 known moons. Miranda and some of its neighboring moons tug on each other as they orbit. This would lead to deformations and friction that would warm the moons’ interiors. The scientists found that Miranda and its nearby moons once likely had what is called an orbital resonance. For example, one moon might make one orbit of Uranus in the same time it takes another moon to orbit twice.
But today, the moons no longer have this synchronicity. So that means their insides are cooling and freezing. But the scientists said Miranda is not completely cool yet. If it were, they would be able to see cracks on its surface from the expansion as the liquid turned to ice. And so Miranda may still have an ocean today. The remaining ocean would probably be quite smaller than what it would have been some 100 to 500 million years ago. Still, Strom said:
But the suggestion of an ocean inside one of the most distant moons in the solar system is remarkable.
Other moons in our solar system with possible oceans
One of the remarkable aspects of the discovery is that ocean moons in our solar system are locations where scientists believe life could exist. Currently, Jupiter’s Europa and Saturn’s Enceladus are the top contenders for icy worlds that harbor hidden oceans. On October 14, 2024, NASA launched the Europa Clipper mission toward Jupiter’s icy moon Enceladus. Scientists want to know more about the habitability – the ability for some form of live to exist – on this large moon.
There’s also ESA’s JUICE mission – JUICE stands for JUpiter Icy Moons Explorer – which launched in 2023 and will explore the icy Jovian moons when it arrives in 2031. And Saturn’s moon Enceladus is a top target for a future ESA mission. Co-author Alex Patthoff of the Planetary Science Institute compared the surprise of Miranda to the one scientists previously got from Enceladus. Patthoff said:
Few scientists expected Enceladus to be geologically active. However, it’s shooting water vapor and ice out of its southern hemisphere as we speak.
Perhaps one day Miranda and other moons of Uranus will get missions of their own.
Bottom line: A new study of Uranus’s moon Miranda looked at its crazy surface and used computer models to see how it might have gotten that way. The best fit for the jumbled terrain is an underground ocean.
Uranus is the sixth planet from the sun in our solar system, orbiting some 19 times farther away from the sun than Earth does. One of its moons, Miranda, is 1/7 the size of our moon and has a crazy-quilt surface of scarps and craters. On October 28, 2024, researchers from Johns Hopkins University said they’ve modeled how the interior structure of the moon could create the bizarre surface patterns. The model with the best fit required the existence of a vast ocean beneath Miranda’s ice some 100 to 500 million years ago. Co-author Tom Nordheim of Johns Hopkins said:
To find evidence of an ocean inside a small object like Miranda is incredibly surprising. It helps build on the story that some of these moons at Uranus may be really interesting … that there may be several ocean worlds around one of the most distant planets in our solar system, which is both exciting and bizarre.
The researchers published their peer-reviewed findings in The Planetary Science Journal on October 15, 2024.
Evidence for an ocean
The only part of Miranda we’ve seen is its southern hemisphere. Scientists believe its grooved terrain (pockmarked with craters) is a result of heating from the moon’s internal tidal forces. The team of scientists took another look at the Voyager 2 images and decided to try to work backward:
to uncover what the moon’s interior structure must have been to shape the moon’s geology in response to tidal forcing.
Lead author Caleb Strom, a graduate student at the University of North Dakota, worked with scientists from the Planetary Science Institute in Arizona. They mapped Miranda’s surface features and then used computer models to match the stress patterns to the moon.
What they found was the best match required a vast ocean under Miranda’s surface. The ocean would have to be no more than 19 miles (30 km) beneath the moon’s crust of ice. And the ocean itself would have to be at least 62 miles (100 km) deep. The little moon is only 292 miles (470 km) across. So the ocean would take up a big chunk of the moon’s interior. Strom said:
That result was a big surprise to the team.
A thin ocean might remain under ice on Uranus’s moon
Uranus has 28 known moons. Miranda and some of its neighboring moons tug on each other as they orbit. This would lead to deformations and friction that would warm the moons’ interiors. The scientists found that Miranda and its nearby moons once likely had what is called an orbital resonance. For example, one moon might make one orbit of Uranus in the same time it takes another moon to orbit twice.
But today, the moons no longer have this synchronicity. So that means their insides are cooling and freezing. But the scientists said Miranda is not completely cool yet. If it were, they would be able to see cracks on its surface from the expansion as the liquid turned to ice. And so Miranda may still have an ocean today. The remaining ocean would probably be quite smaller than what it would have been some 100 to 500 million years ago. Still, Strom said:
But the suggestion of an ocean inside one of the most distant moons in the solar system is remarkable.
Other moons in our solar system with possible oceans
One of the remarkable aspects of the discovery is that ocean moons in our solar system are locations where scientists believe life could exist. Currently, Jupiter’s Europa and Saturn’s Enceladus are the top contenders for icy worlds that harbor hidden oceans. On October 14, 2024, NASA launched the Europa Clipper mission toward Jupiter’s icy moon Enceladus. Scientists want to know more about the habitability – the ability for some form of live to exist – on this large moon.
There’s also ESA’s JUICE mission – JUICE stands for JUpiter Icy Moons Explorer – which launched in 2023 and will explore the icy Jovian moons when it arrives in 2031. And Saturn’s moon Enceladus is a top target for a future ESA mission. Co-author Alex Patthoff of the Planetary Science Institute compared the surprise of Miranda to the one scientists previously got from Enceladus. Patthoff said:
Few scientists expected Enceladus to be geologically active. However, it’s shooting water vapor and ice out of its southern hemisphere as we speak.
Perhaps one day Miranda and other moons of Uranus will get missions of their own.
Bottom line: A new study of Uranus’s moon Miranda looked at its crazy surface and used computer models to see how it might have gotten that way. The best fit for the jumbled terrain is an underground ocean.
It’s that time of year again, when creepy-crawlies and spine-chilling images tickle our imaginations. One of the spookiest views in the night sky is of the Witch Head Nebula, with the catalog designation IC 2118. The Witch Head Nebula is located near Orion’s brightest star, Rigel. But Rigel is just outside the image above, so the witch gets all the attention. If the field of view was large enough to include the blue supergiant star, you could see that the witch appears to be gazing at Rigel.
The constellation Orion, accompanied by the Witch Head Nebula, rises from the eastern horizon before midnight on Halloween. This lengthy nebula spans 70 light-years across and lies 900 light-years from Earth. The nebula is extraordinarily faint, at magnitude 13, so it can only be spotted with large telescopes.
Scientists think it might be an ancient supernova remnant. The Witch Head Nebula is categorized as a reflection nebula, or one that shines with the aid of a nearby star. In this case, Rigel shines its bright light on the gas and dust to create the reflection that we see. The dust reflects more blue light than red, which gives it its eerie purplish-blue hue.
Want to learn how to “capture the witch” on film? Try this post from the Galactic Hunter.
Bottom line: The Witch Head Nebula rises near the star Rigel in Orion on Halloween night, but you need a telescope to see it.
It’s that time of year again, when creepy-crawlies and spine-chilling images tickle our imaginations. One of the spookiest views in the night sky is of the Witch Head Nebula, with the catalog designation IC 2118. The Witch Head Nebula is located near Orion’s brightest star, Rigel. But Rigel is just outside the image above, so the witch gets all the attention. If the field of view was large enough to include the blue supergiant star, you could see that the witch appears to be gazing at Rigel.
The constellation Orion, accompanied by the Witch Head Nebula, rises from the eastern horizon before midnight on Halloween. This lengthy nebula spans 70 light-years across and lies 900 light-years from Earth. The nebula is extraordinarily faint, at magnitude 13, so it can only be spotted with large telescopes.
Scientists think it might be an ancient supernova remnant. The Witch Head Nebula is categorized as a reflection nebula, or one that shines with the aid of a nearby star. In this case, Rigel shines its bright light on the gas and dust to create the reflection that we see. The dust reflects more blue light than red, which gives it its eerie purplish-blue hue.
Want to learn how to “capture the witch” on film? Try this post from the Galactic Hunter.
Bottom line: The Witch Head Nebula rises near the star Rigel in Orion on Halloween night, but you need a telescope to see it.
Porcupines are calm and peaceful rodents that live in many parts of the world. There are two families of porcupines with different lifestyles. But if they have something in common, it is the painful weapon they won’t hesitate to use if they feel threatened: sharp quills.
Porcupines were first discovered in Africa. And there are around 29 species of porcupines throughout the world. These are adaptable creatures that can live in various terrain from rocky to semi-arid areas, deserts, savannahs, grasslands, forests and tropical jungles. Porcupines are classified into two families, those of the Old World, which are found in Europe, Africa and Asia, and those of the New World, which are located in the Americas.
The Old World porcupine
Old World porcupines are larger than their New World counterparts. With a length of between 25 and 35 inches (60 and 90 cm), Old World porcupines can weigh between 22 and 55 pounds (10 and 25 kg). They have a life expectancy of 15 years in the wild, although in captivity they live up to 20 years because they face fewer threats.
Their front legs have four fingers armed with strong claws, while the hind legs have five fingers. They have short legs and therefore move slowly. But when in danger, they can speed up. However, who needs to run when you have an impressive defense? If these striking animals stand out for something, it is for their quills.
What are porcupines’ quills like?
These animals actually have soft brown or black hair on their faces, necks and the lower parts of their bodies. But they also have thick bristles on their heads and the napes of their necks, and sharp quills on their backs, sides and tails. The lower half of the back contains the longest quills, which can measure up to 12 inches (30 cm).
These are modified hairs wrapped in a thick keratin duct; therefore, they are hollow inside. The quills originate in the musculature of the skin, and in the case of Old World porcupines, they are found in groups or clusters. On the outside, the quills have black and white stripes.
Do porcupine quills contain poison?
Porcupines warn their enemies many times. When the porcupine feels threatened, it stomps heavily on the ground and trembles deliberately to rattle its quills and scare anyone who disturbs its peace. Ultimately, it bristles and raises its quills in warning, making it appear larger.
If its enemy still persists, then the porcupine moves sideways or backward to charge at its enemy and prick them with its larger, backside quills.
It’s not true that porcupines can throw their quills. When the quills come into contact with another body, they break off, but porcupines do not shoot them. In addition, they are quite fragile and when they enter the victim’s body they break, leaving behind fragments.
Regarding the poison … the wounds from a porcupine are quite painful, which is why people think they’re poisonous. The problem is if the wounds are not treated, they can become infected. In the wild, animals that attack porcupines can die from infection.
Another curious fact about their spikes is besides being good defense, quills don’t sink in water. This makes porcupines great swimmers. So quills are both a formidable weapon and tool. Two in one!
What else is there to know about this rodent?
Well, like all rodents, porcupines have large incisor teeth that they have to wear down, since they constantly grow. Furthermore, these incisors are extremely strong, so much so that they can even break through wire.
Porcupines are silent animals. It’s rare to hear their vocalizations, but in case of discontent or anxiety, these animals growl. On the other hand, they do not have a very developed sense of hearing or sight, since their eyes and ears are quite small. However, they do have an incredible sense of smell.
What do porcupines eat?
These are mainly herbivorous animals. Thus, they eat all parts of the plants. They also eat fruits, bulbs and seeds. In the absence of other food, they eat insects and small vertebrates. Additionally, they can eat carrion. It is common to see them gnawing on bones, since it provides them with calcium and lets them wear down their teeth at the same time. Likewise, they constantly gnaw the bark of trees.
Porcupines are nocturnal animals. They feed at night and in pairs. The male and female walk side by side, or the male stays a little behind his mate.
Home sweet home
During the day, these animals usually hide in rock crevices, caves and burrows. It turns out that porcupines are good diggers, since they have strong legs with claws.
The burrows can reach 33 feet (10 meters) in length and a depth of up to 13 feet (4 meters). In winter their activity is significantly reduced and they spend most of their time in their burrows, although they do not hibernate. Additionally, porcupines do not tolerate the cold well, so even though they are nocturnal, they often stay in their burrows at night if it is cold.
Family life
Our prickly friends form monogamous pairs and live in their burrows in small family groups.
Normally, the female breeds only once a year and has one or two babies per litter, although she can have four babies. Gestation lasts 93 to 105 days, and the offspring are born fully formed, with their eyes open and teeth developed. They are even born with spines, although they are soft and flexible to facilitate birth. These harden after a few days.
The babies do not leave the burrow until they stop drinking milk, at two months. Afterward, they accompany their parents on their nights out to learn what to do. The babies learn from their parents by repetition. And there is no need to be scared about babies’ safety, since the quills harden quickly and they have attentive parents who take care of them.
The New World porcupine
The members of this family are more agile, since they are small or medium-sized. They measure 8 to 21 inches (20 to 53 cm) long and weigh about 9 pounds (4 kg). They live about 15 years in the wild and 20 in captivity.
This family of porcupines has developed a practically arboreal life. In fact, they live among tree branches and barely touch the ground. To make it easier for them to move between the branches, they have long, flexible tails, about 19 inches (48 cm) in some species. They cling to the branches as monkeys do.
New World porcupines have many strong quills that grow close together on all parts of the body, except the snout, underside and tail. In fact, the tails do not have quills because otherwise they would constantly break when in contact with the branches. Likewise, the feet have wide pads and four strong claws bent inward to move comfortably among trees.
How are the two porcupines different?
The New World porcupine has a covering of thick hair combined with thick bristles and quills. Its quills are shorter and individual. Additionally, the quills of New World porcupines do not break when they hit their victim.
The quills of some New World species are coated with fatty acids that contain bactericidal properties. Porcupines that spend a lot of time in trees sometimes fall and are likely to be injured by their own quills. Bactericidal properties protect them from infections.
In the event of a threat, Old World porcupines tend to fight, while New World porcupines flee and climb trees.
The gestation of tree porcupines lasts about 200 days. Females give birth to one single baby. The offspring is born covered in hair and small spines that harden after birth. The difference is that as soon as the New World porcupine is born, it’s ready to climb trees. Weaning occurs around 10 weeks of age.
What do both families have in common?
Well, they both have long whiskers. These are highly sensitive hairs that act as tactile organs, allowing porcupines to explore their environment and detect nearby objects. Also, in both cases, when the quills detach from the body, they grow back. Awesome!
New World porcupines are also nocturnal and spend the day sleeping curled up on branches. Likewise, they are herbivores, since they feed on leaves and tender shoots, and they love fruit. Their incisors are also large and do not stop growing, so rodents in this family also gnaw the bark of trees to obtain nutrients and to wear down teeth.
And did you know that sexual dimorphism exists in porcupines? This means that one gender is different from the other in some aspect. In this case, the female is larger than the male. It’s a good way to know their gender without touching them!
More New World porcupine images
Bottom line: Porcupines are peaceful rodents, but if they feel threatened, they have a dangerous weapon they are not afraid to use: sharp quills.
Porcupines are calm and peaceful rodents that live in many parts of the world. There are two families of porcupines with different lifestyles. But if they have something in common, it is the painful weapon they won’t hesitate to use if they feel threatened: sharp quills.
Porcupines were first discovered in Africa. And there are around 29 species of porcupines throughout the world. These are adaptable creatures that can live in various terrain from rocky to semi-arid areas, deserts, savannahs, grasslands, forests and tropical jungles. Porcupines are classified into two families, those of the Old World, which are found in Europe, Africa and Asia, and those of the New World, which are located in the Americas.
The Old World porcupine
Old World porcupines are larger than their New World counterparts. With a length of between 25 and 35 inches (60 and 90 cm), Old World porcupines can weigh between 22 and 55 pounds (10 and 25 kg). They have a life expectancy of 15 years in the wild, although in captivity they live up to 20 years because they face fewer threats.
Their front legs have four fingers armed with strong claws, while the hind legs have five fingers. They have short legs and therefore move slowly. But when in danger, they can speed up. However, who needs to run when you have an impressive defense? If these striking animals stand out for something, it is for their quills.
What are porcupines’ quills like?
These animals actually have soft brown or black hair on their faces, necks and the lower parts of their bodies. But they also have thick bristles on their heads and the napes of their necks, and sharp quills on their backs, sides and tails. The lower half of the back contains the longest quills, which can measure up to 12 inches (30 cm).
These are modified hairs wrapped in a thick keratin duct; therefore, they are hollow inside. The quills originate in the musculature of the skin, and in the case of Old World porcupines, they are found in groups or clusters. On the outside, the quills have black and white stripes.
Do porcupine quills contain poison?
Porcupines warn their enemies many times. When the porcupine feels threatened, it stomps heavily on the ground and trembles deliberately to rattle its quills and scare anyone who disturbs its peace. Ultimately, it bristles and raises its quills in warning, making it appear larger.
If its enemy still persists, then the porcupine moves sideways or backward to charge at its enemy and prick them with its larger, backside quills.
It’s not true that porcupines can throw their quills. When the quills come into contact with another body, they break off, but porcupines do not shoot them. In addition, they are quite fragile and when they enter the victim’s body they break, leaving behind fragments.
Regarding the poison … the wounds from a porcupine are quite painful, which is why people think they’re poisonous. The problem is if the wounds are not treated, they can become infected. In the wild, animals that attack porcupines can die from infection.
Another curious fact about their spikes is besides being good defense, quills don’t sink in water. This makes porcupines great swimmers. So quills are both a formidable weapon and tool. Two in one!
What else is there to know about this rodent?
Well, like all rodents, porcupines have large incisor teeth that they have to wear down, since they constantly grow. Furthermore, these incisors are extremely strong, so much so that they can even break through wire.
Porcupines are silent animals. It’s rare to hear their vocalizations, but in case of discontent or anxiety, these animals growl. On the other hand, they do not have a very developed sense of hearing or sight, since their eyes and ears are quite small. However, they do have an incredible sense of smell.
What do porcupines eat?
These are mainly herbivorous animals. Thus, they eat all parts of the plants. They also eat fruits, bulbs and seeds. In the absence of other food, they eat insects and small vertebrates. Additionally, they can eat carrion. It is common to see them gnawing on bones, since it provides them with calcium and lets them wear down their teeth at the same time. Likewise, they constantly gnaw the bark of trees.
Porcupines are nocturnal animals. They feed at night and in pairs. The male and female walk side by side, or the male stays a little behind his mate.
Home sweet home
During the day, these animals usually hide in rock crevices, caves and burrows. It turns out that porcupines are good diggers, since they have strong legs with claws.
The burrows can reach 33 feet (10 meters) in length and a depth of up to 13 feet (4 meters). In winter their activity is significantly reduced and they spend most of their time in their burrows, although they do not hibernate. Additionally, porcupines do not tolerate the cold well, so even though they are nocturnal, they often stay in their burrows at night if it is cold.
Family life
Our prickly friends form monogamous pairs and live in their burrows in small family groups.
Normally, the female breeds only once a year and has one or two babies per litter, although she can have four babies. Gestation lasts 93 to 105 days, and the offspring are born fully formed, with their eyes open and teeth developed. They are even born with spines, although they are soft and flexible to facilitate birth. These harden after a few days.
The babies do not leave the burrow until they stop drinking milk, at two months. Afterward, they accompany their parents on their nights out to learn what to do. The babies learn from their parents by repetition. And there is no need to be scared about babies’ safety, since the quills harden quickly and they have attentive parents who take care of them.
The New World porcupine
The members of this family are more agile, since they are small or medium-sized. They measure 8 to 21 inches (20 to 53 cm) long and weigh about 9 pounds (4 kg). They live about 15 years in the wild and 20 in captivity.
This family of porcupines has developed a practically arboreal life. In fact, they live among tree branches and barely touch the ground. To make it easier for them to move between the branches, they have long, flexible tails, about 19 inches (48 cm) in some species. They cling to the branches as monkeys do.
New World porcupines have many strong quills that grow close together on all parts of the body, except the snout, underside and tail. In fact, the tails do not have quills because otherwise they would constantly break when in contact with the branches. Likewise, the feet have wide pads and four strong claws bent inward to move comfortably among trees.
How are the two porcupines different?
The New World porcupine has a covering of thick hair combined with thick bristles and quills. Its quills are shorter and individual. Additionally, the quills of New World porcupines do not break when they hit their victim.
The quills of some New World species are coated with fatty acids that contain bactericidal properties. Porcupines that spend a lot of time in trees sometimes fall and are likely to be injured by their own quills. Bactericidal properties protect them from infections.
In the event of a threat, Old World porcupines tend to fight, while New World porcupines flee and climb trees.
The gestation of tree porcupines lasts about 200 days. Females give birth to one single baby. The offspring is born covered in hair and small spines that harden after birth. The difference is that as soon as the New World porcupine is born, it’s ready to climb trees. Weaning occurs around 10 weeks of age.
What do both families have in common?
Well, they both have long whiskers. These are highly sensitive hairs that act as tactile organs, allowing porcupines to explore their environment and detect nearby objects. Also, in both cases, when the quills detach from the body, they grow back. Awesome!
New World porcupines are also nocturnal and spend the day sleeping curled up on branches. Likewise, they are herbivores, since they feed on leaves and tender shoots, and they love fruit. Their incisors are also large and do not stop growing, so rodents in this family also gnaw the bark of trees to obtain nutrients and to wear down teeth.
And did you know that sexual dimorphism exists in porcupines? This means that one gender is different from the other in some aspect. In this case, the female is larger than the male. It’s a good way to know their gender without touching them!
More New World porcupine images
Bottom line: Porcupines are peaceful rodents, but if they feel threatened, they have a dangerous weapon they are not afraid to use: sharp quills.
Scientists discover ocean animals beneath the seafloor
For the first time, researchers have discovered animal communities thriving beneath the bottom of the ocean. They found the ocean animals – including giant tubeworms and sea snails – below hydrothermal vents some 8,250 feet (2,515 m) from the Pacific Ocean’s surface. And they said these seafloor and subseafloor communities connect through passageways at the bottom of the ocean.
The scientists, led by Monika Bright of the Schmidt Ocean Institute, made the discovery during an expedition in the summer of 2023. And now they’ve released a paper detailing their findings. The peer-reviewed journal Naturepublished the paper on October 15, 2024.
Thriving communities beneath hydrothermal vents
We’ve known that animal communities thrive around hydrothermal vents since the discovery of these ocean features in 1977. Hydrothermal vents are like hot springs on the seafloor, where seawater seeps through cracks in the ocean crust and magma superheats it from below. This causes the heated water to rise with force, dissolving minerals from the crust as it does so. And the spreading of minerals allows animals to live around the vents. But it was thought that only microbes and viruses were hardy enough to live beneath them.
But now we know the space below these vents is habitable for animal life, too. Exploring a part of the volcanic mid-ocean ridge known as the East Pacific Rise, Bright’s research team used the Schmidt Ocean Institute’s underwater robot SuBastian to peel back small sections of the seafloor. They found roughly 4-inch (10-cm) tall cavities teeming with life. Volcanic activity heats the water in the cavities to a balmy 77 degrees F (25 C), making it a suitable home for creatures including giant tubeworms, polychaete worms, mussels and sea snails.
Ocean animals take pathways from above to below the seafloor
One of the key findings of the new paper centers on the giant tubeworm Riftia pachyptila. This species is a common feature of hydrothermal vents, but few tubeworm larvae have been found in the ocean around them. How do the larvae make their way to new vents? The team hypothesized they could be traveling through passages beneath the seafloor. And that’s exactly what they found: Giant tubeworm larvae, the scientists said, are able to traverse these cavities until they come across new hydrothermal habitats. Vent currents then draw some of them to the seafloor. But others simply settle and mature in the cavities below.
So not only has the team discovered a new ecosystem below the seafloor, but they’ve established that it’s intertwined with the seafloor community. Bright said:
Two dynamic vent habitats exist. Vent animals above and below the surface thrive together in unison, depending on vent fluid from below and oxygen in the seawater from above.
A new ecosystem to protect
We don’t yet know how far these hidden communities could spread, or how widespread they might be. The team is planning further investigation. They hope more knowledge could aid a push for better management of the ocean floor. In particular, they highlighted the urgency of protecting this newfound habitat from deep-sea mining.
Bottom line: Scientists have discovered ocean animals beneath the bottom of the ocean, where worms and snails thrive in cavities beneath hydrothermal vents.
Scientists discover ocean animals beneath the seafloor
For the first time, researchers have discovered animal communities thriving beneath the bottom of the ocean. They found the ocean animals – including giant tubeworms and sea snails – below hydrothermal vents some 8,250 feet (2,515 m) from the Pacific Ocean’s surface. And they said these seafloor and subseafloor communities connect through passageways at the bottom of the ocean.
The scientists, led by Monika Bright of the Schmidt Ocean Institute, made the discovery during an expedition in the summer of 2023. And now they’ve released a paper detailing their findings. The peer-reviewed journal Naturepublished the paper on October 15, 2024.
Thriving communities beneath hydrothermal vents
We’ve known that animal communities thrive around hydrothermal vents since the discovery of these ocean features in 1977. Hydrothermal vents are like hot springs on the seafloor, where seawater seeps through cracks in the ocean crust and magma superheats it from below. This causes the heated water to rise with force, dissolving minerals from the crust as it does so. And the spreading of minerals allows animals to live around the vents. But it was thought that only microbes and viruses were hardy enough to live beneath them.
But now we know the space below these vents is habitable for animal life, too. Exploring a part of the volcanic mid-ocean ridge known as the East Pacific Rise, Bright’s research team used the Schmidt Ocean Institute’s underwater robot SuBastian to peel back small sections of the seafloor. They found roughly 4-inch (10-cm) tall cavities teeming with life. Volcanic activity heats the water in the cavities to a balmy 77 degrees F (25 C), making it a suitable home for creatures including giant tubeworms, polychaete worms, mussels and sea snails.
Ocean animals take pathways from above to below the seafloor
One of the key findings of the new paper centers on the giant tubeworm Riftia pachyptila. This species is a common feature of hydrothermal vents, but few tubeworm larvae have been found in the ocean around them. How do the larvae make their way to new vents? The team hypothesized they could be traveling through passages beneath the seafloor. And that’s exactly what they found: Giant tubeworm larvae, the scientists said, are able to traverse these cavities until they come across new hydrothermal habitats. Vent currents then draw some of them to the seafloor. But others simply settle and mature in the cavities below.
So not only has the team discovered a new ecosystem below the seafloor, but they’ve established that it’s intertwined with the seafloor community. Bright said:
Two dynamic vent habitats exist. Vent animals above and below the surface thrive together in unison, depending on vent fluid from below and oxygen in the seawater from above.
A new ecosystem to protect
We don’t yet know how far these hidden communities could spread, or how widespread they might be. The team is planning further investigation. They hope more knowledge could aid a push for better management of the ocean floor. In particular, they highlighted the urgency of protecting this newfound habitat from deep-sea mining.
Bottom line: Scientists have discovered ocean animals beneath the bottom of the ocean, where worms and snails thrive in cavities beneath hydrothermal vents.
Is Earth surrounded by potentially dangerous dark comets? These mysterious rocky bodies combine characteristics of both asteroids and comets. But how many dark comets are out there? And do they pose a threat to Earth? Find out at 12:15 p.m. CT (17:15 UTC) on Monday, October 28 when EarthSky’s Dave Adalian chats live with astronomer and dark comet discoverer Aster G. Taylor.
Dark comets discoverer to join EarthSky live Monday
At 12:15 p.m. CDT (17:15 UTC) on Monday, October 28, dark comet discoverer Aster Taylor will join EarthSky’s Dave Adalian for a live chat. Head over to YouTube to watch the trailer now. While you’re there, turn on notifications and share the link.
Meanwhile, to find out all about Taylor’s discovery read the story below. Then ask your dark comet questions right now. Put them in the chat today … Get your answers during the stream!
Dark comets might surround the Earth
Up to 60% of near-Earth objects could be dark comets. Dark comets are mysterious asteroids that orbit the sun in our solar system. They likely contain or previously contained ice and could have been a route for delivering water to Earth. That’s according to Aster Taylor of the University of Michigan, lead author of a new study published in the peer-reviewed journal Icarus on July 6, 2024.
The findings suggest that asteroids in the asteroid belt – a region between Jupiter and Mars that contains much of the solar system’s rocky asteroids – have subsurface ice. According to Taylor, scientists have suspected this since the 1980s. The study also shows a potential pathway for delivering ice into the near-Earth solar system, Taylor says. How Earth got its water is a longstanding question.
We don’t know if these dark comets delivered water to Earth. We can’t say that. But we can say that there is still debate over how exactly the Earth’s water got here. The work we’ve done has shown that this is another pathway to get ice from somewhere in the rest of the solar system to the Earth’s environment.
The research further suggests that one large object may come from the Jupiter-family comets, comets whose orbits take them close to the planet Jupiter.
A comet mixed with an asteroid
Dark comets are a bit of a mystery, because they combine characteristics of both asteroids and comets. Asteroids are rocky bodies with no ice that orbit closer to the sun, typically within what’s called the ice line. This means they’re close enough to the sun for any ice the asteroid may have been carrying to sublimate, or change from solid ice directly into gas.
Comets are icy bodies that show a fuzzy coma, a cloud that often surrounds a comet. Sublimating ice carries dust along with it, creating the cloud. Additionally, comets typically have slight accelerations propelled not by gravity, but by the sublimation of ice, called nongravitational accelerations.
The study examined seven dark comets and estimates that between 0.5% and 60% of all near-Earth objects could be dark comets, which do not have comae but do have nongravitational accelerations. The researchers also suggest that these dark comets likely come from the asteroid belt. And because these dark comets have nongravitational accelerations, the study findings suggest asteroids in the asteroid belt contain ice. Taylor said:
We think these objects came from the inner and/or outer main asteroid belt, and the implication of that is that this is another mechanism for getting some ice into the inner solar system. There may be more ice in the inner main belt than we thought. There may be more objects like this out there. This could be a significant fraction of the nearest population. We don’t really know, but we have many more questions because of these findings.
Dark comets come from the asteroid belt
In previous work, a team of researchers including Taylor identified nongravitational accelerations on a set of near-Earth objects, naming them dark comets. They determined the dark comets’ nongravitational accelerations are likely the result of small amounts of sublimating ice.
In the current work, Taylor and colleagues wanted to discover where the dark comets came from. The researchers said:
Near-Earth objects don’t stay on their current orbits very long, because the near-Earth environment is messy. They only stay in the near-Earth environment for around 10 million years. Because the solar system is much older than that, that means near-Earth objects are coming from somewhere … that we’re constantly being fed near-Earth objects from another, much larger source.
To determine the origin of this dark comet population, Taylor and co-authors created dynamical models that assigned nongravitational accelerations to objects from different populations. Then, they modeled a path these objects would follow given the assigned nongravitational accelerations over a period of 100,000 years. The researchers observed many of these objects ended up where dark comets are today. And they found that out of all potential sources, the main asteroid belt is the most likely place of origin.
But not all …
One of the dark comets – called 2003 RM – passes in an elliptical orbit close to Earth, then out to Jupiter and back past Earth. 2003 RM follows the same path that would be expected from a Jupiter-family comet. That is, its position is consistent with a comet that was knocked inward from its orbit.
Ice in the asteroid belt
Meanwhile, the study finds the rest of the dark comets likely came from the inner band of the asteroid belt. Since the dark comets likely have ice, this shows ice is present in the inner main belt.
Breaking into pieces
Then, the researchers applied a previously suggested theory to their population of dark comets to determine why the objects are so small and quickly rotating. Comets are rocky structures bound together by ice. Picture a dirty ice cube, Taylor said. Once they get bumped within the solar system’s ice line, that ice starts to off-gas. This causes the object’s acceleration. But it can also cause the object to spin quite fast … fast enough for the object to break apart. Taylor said:
These pieces will also have ice on them, so they will also spin out faster and faster until they break into more pieces. You can just keep doing this as you get smaller and smaller and smaller. What we suggest is that the way you get these small, fast rotating objects is you take a few bigger objects and break them into pieces.
As this happens, the objects continue to lose their ice, get even smaller, and rotate even more rapidly.
The researchers believe that while the larger dark comet, 2003 RM, was likely a larger object that got kicked out of the outer main belt of the asteroid belt, the six other objects they were examining likely came from the inner main belt and were made by an object that had gotten knocked inward and then broke apart.
Bottom line: Dark comets are icy bodies that likely come from the inner band of the asteroid belt. Approximately 60% of near-Earth objects may be dark comets.
Is Earth surrounded by potentially dangerous dark comets? These mysterious rocky bodies combine characteristics of both asteroids and comets. But how many dark comets are out there? And do they pose a threat to Earth? Find out at 12:15 p.m. CT (17:15 UTC) on Monday, October 28 when EarthSky’s Dave Adalian chats live with astronomer and dark comet discoverer Aster G. Taylor.
Dark comets discoverer to join EarthSky live Monday
At 12:15 p.m. CDT (17:15 UTC) on Monday, October 28, dark comet discoverer Aster Taylor will join EarthSky’s Dave Adalian for a live chat. Head over to YouTube to watch the trailer now. While you’re there, turn on notifications and share the link.
Meanwhile, to find out all about Taylor’s discovery read the story below. Then ask your dark comet questions right now. Put them in the chat today … Get your answers during the stream!
Dark comets might surround the Earth
Up to 60% of near-Earth objects could be dark comets. Dark comets are mysterious asteroids that orbit the sun in our solar system. They likely contain or previously contained ice and could have been a route for delivering water to Earth. That’s according to Aster Taylor of the University of Michigan, lead author of a new study published in the peer-reviewed journal Icarus on July 6, 2024.
The findings suggest that asteroids in the asteroid belt – a region between Jupiter and Mars that contains much of the solar system’s rocky asteroids – have subsurface ice. According to Taylor, scientists have suspected this since the 1980s. The study also shows a potential pathway for delivering ice into the near-Earth solar system, Taylor says. How Earth got its water is a longstanding question.
We don’t know if these dark comets delivered water to Earth. We can’t say that. But we can say that there is still debate over how exactly the Earth’s water got here. The work we’ve done has shown that this is another pathway to get ice from somewhere in the rest of the solar system to the Earth’s environment.
The research further suggests that one large object may come from the Jupiter-family comets, comets whose orbits take them close to the planet Jupiter.
A comet mixed with an asteroid
Dark comets are a bit of a mystery, because they combine characteristics of both asteroids and comets. Asteroids are rocky bodies with no ice that orbit closer to the sun, typically within what’s called the ice line. This means they’re close enough to the sun for any ice the asteroid may have been carrying to sublimate, or change from solid ice directly into gas.
Comets are icy bodies that show a fuzzy coma, a cloud that often surrounds a comet. Sublimating ice carries dust along with it, creating the cloud. Additionally, comets typically have slight accelerations propelled not by gravity, but by the sublimation of ice, called nongravitational accelerations.
The study examined seven dark comets and estimates that between 0.5% and 60% of all near-Earth objects could be dark comets, which do not have comae but do have nongravitational accelerations. The researchers also suggest that these dark comets likely come from the asteroid belt. And because these dark comets have nongravitational accelerations, the study findings suggest asteroids in the asteroid belt contain ice. Taylor said:
We think these objects came from the inner and/or outer main asteroid belt, and the implication of that is that this is another mechanism for getting some ice into the inner solar system. There may be more ice in the inner main belt than we thought. There may be more objects like this out there. This could be a significant fraction of the nearest population. We don’t really know, but we have many more questions because of these findings.
Dark comets come from the asteroid belt
In previous work, a team of researchers including Taylor identified nongravitational accelerations on a set of near-Earth objects, naming them dark comets. They determined the dark comets’ nongravitational accelerations are likely the result of small amounts of sublimating ice.
In the current work, Taylor and colleagues wanted to discover where the dark comets came from. The researchers said:
Near-Earth objects don’t stay on their current orbits very long, because the near-Earth environment is messy. They only stay in the near-Earth environment for around 10 million years. Because the solar system is much older than that, that means near-Earth objects are coming from somewhere … that we’re constantly being fed near-Earth objects from another, much larger source.
To determine the origin of this dark comet population, Taylor and co-authors created dynamical models that assigned nongravitational accelerations to objects from different populations. Then, they modeled a path these objects would follow given the assigned nongravitational accelerations over a period of 100,000 years. The researchers observed many of these objects ended up where dark comets are today. And they found that out of all potential sources, the main asteroid belt is the most likely place of origin.
But not all …
One of the dark comets – called 2003 RM – passes in an elliptical orbit close to Earth, then out to Jupiter and back past Earth. 2003 RM follows the same path that would be expected from a Jupiter-family comet. That is, its position is consistent with a comet that was knocked inward from its orbit.
Ice in the asteroid belt
Meanwhile, the study finds the rest of the dark comets likely came from the inner band of the asteroid belt. Since the dark comets likely have ice, this shows ice is present in the inner main belt.
Breaking into pieces
Then, the researchers applied a previously suggested theory to their population of dark comets to determine why the objects are so small and quickly rotating. Comets are rocky structures bound together by ice. Picture a dirty ice cube, Taylor said. Once they get bumped within the solar system’s ice line, that ice starts to off-gas. This causes the object’s acceleration. But it can also cause the object to spin quite fast … fast enough for the object to break apart. Taylor said:
These pieces will also have ice on them, so they will also spin out faster and faster until they break into more pieces. You can just keep doing this as you get smaller and smaller and smaller. What we suggest is that the way you get these small, fast rotating objects is you take a few bigger objects and break them into pieces.
As this happens, the objects continue to lose their ice, get even smaller, and rotate even more rapidly.
The researchers believe that while the larger dark comet, 2003 RM, was likely a larger object that got kicked out of the outer main belt of the asteroid belt, the six other objects they were examining likely came from the inner main belt and were made by an object that had gotten knocked inward and then broke apart.
Bottom line: Dark comets are icy bodies that likely come from the inner band of the asteroid belt. Approximately 60% of near-Earth objects may be dark comets.