Spectacular new Spinosaurus found in Niger, Africa

Artist’s depiction of a fearsome-looking Spinosaurus mirabilis standing at the river’s edge. This newly discovered species, one of the last spinosaurid species before they went extinct, lived 95 million years ago in present-day Niger, Africa. Image via Dani Navarro/ University of Chicago. Used with permission.

• Scientists discovered a new dinosaur species, Spinosaurus mirabilis, in the Sahara Desert of Niger.
• The new species had a tall, scimitar-shaped head crest and lived about 95 million years ago, hunting fish in rivers.
• This discovery suggests spinosaurs might have lived inland in forested river habitats, not just near the coast.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

Newly discovered dinosaur had an eye-catching head crest

Spinosaurs were large dinosaurs that lived about 100 to 94 million years ago. They were notable for distinctive projections on their backs that looked like sails. Scientists first discovered this dinosaur genus in 1915, and for a long time, there was just one recognized species. But on February 19, 2026, a research team led by Paul Sereno, a paleontologist at the University of Chicago, said they’ve discovered a new spinosaur species in the Central Sahara Desert. They named it Spinosaurus mirabilis – mirabilis means “astonishing” in Latin – because it had an unusual, tall crest on its head.

Sereno said:

This find was so sudden and amazing, it was really emotional for our team. I’ll forever cherish the moment in camp when we crowded around a laptop to look at the new species for the first time, after one member of our team generated 3D digital models of the bones we found to assemble the skull, on solar power in the middle of the Sahara. That’s when the significance of the discovery really registered.

Sereno and his colleagues published their findings in the peer-reviewed journal Nature on February 19, 2026.

University of Chicago paleontologist Paul Sereno led the team that excavated and identified the new spinosaur, Spinosaurus mirabilis. He poses here with the skull cast. Image via Keith Ladzinski/ University of Chicago. Used with permission.

This Spinosaurus was a dramatic-looking creature!

Spinosaurs lived 100 to 94 million years ago in present-day Africa. Until now, researchers only recognized one species, Spinosaurus aegyptiacus. Scientists found those fossils at sites that were once coastal habitats when the animals were alive. Therefore, they thought these dinosaurs could be aquatic or semi-aquatic, capable of hunting for fish in the sea. But the degree to which they took to the water was not clear.

These dinosaurs had upward-projecting bones from their backs, creating stunning sail-like features. The animals likely used the sail for display, and it may have even regulated body temperature. In addition, S. aegyptiacus had a long skull similar to crocodiles, optimized for catching fish.

These unusual dinosaurs became extinct about 94 million years ago, due to a rapid rise in sea level and climate change.

A video of Paul Sereno and his team in the field, in Niger, in 2022. Provided by the University of Chicago.

Finding a new Spinosaurus in Niger

In 2019, a local man in the Republic of Niger led Sereno and his team to a site called Jenguebi that had large fossil bones. Due to the long journey back to camp, the team only had time to grab a few fossils, including teeth and jawbones. But they did not yet know it was a new dinosaur species.

In 2022, Sereno returned to Jenguebi with a larger team. During that expedition, they found more fossils there, as well as many more at a site called Iguidi. In all, they were able to collect incomplete skeletons from several individuals, all of them immature spinosaurs that had not reached adulthood.

He said:

The local people we work with are my lifelong friends, now including the man who led us to Jenguebi and the astonishing spinosaur. They understand the importance of what we’re doing together, for science and for their country.

Dan Vidal, a member of Sereno’s team, with Abdoul Nasser, a guide who led them to the Jenguebi fossil site in 2019. There, they found the first Spinosaurus mirabilis fossils. Image via Alhadji Akamaya/ University of Chicago. Used with permission.

Spinosaurus mirabilis

During the 2022 expedition, as they examined their finds, the team realized they had discovered a species new to science. This spinosaur had an unusually tall head crest. Also, the teeth arrangement in its jaw was a bit different from that of S. aegyptiacus.

The new spinosaur had a crest at the top of the skull that the researchers described as scimitar-shaped. That’s a short sword with a curved blade that becomes broader at its tip. In addition, internal vascular canals and the surface texture of the crest suggested it was once coated in keratin. That’s a fibrous protein found in hair, nails and horns. Moreover, they speculated this crest might have been brightly colored.

Ana Lázaro, a member of Sereno’s 2022 expedition to Niger, holds the most complete head crest found for Spinosaurus mirabilis. Image via Alvaro Simarro/ University of Chicago. Used with permission.

S. mirabilis’ jaws were quite formidable, similar to those of S. aegyptiacus. It had interdigitating upper and lower tooth rows. In other words, the teeth in the lower jaw extended outward. Meanwhile, the lower jaw teeth interlocked with those in the upper jaw. This is a feature that exists in many fish-eating animals in the fossil record, such as ichthyosaurs, pterosaurs and some crocodiles.

These are 2 skull casts of spinosaurs. At the top is the newly discovered Spinosaurus mirabilis, and below it is the previously known Spinosaurus aegyptiacus from North Africa. Image via Keith Ladzinski/ University of Chicago. Used with permission.

The bones they collected all came from subadult animals. Therefore, it’s hard to determine the size of an adult S. mirabilis. However, they were able to establish that the individual initially used to describe the species – the holotype – was about 26 feet (8 meters) long.

New clues to how spinosaurs lived

The previously known S. aegyptiacus was found in North Africa, at locations that were once coastal habitat when the animals were alive. Scientists wondered if spinosaurs were fully aquatic and able to dive for prey. But there was considerable debate about it.

However, this new discovery paints a different picture of how spinosaurs may have lived. About 95 million years ago, Jenguebi was 310 miles (500 km) from the coastline. Iguidi was even further away, about 620 miles (1,000 km). That’s pretty far inland from the ocean.

Moreover, the scientists also found fossils from two long-necked dinosaurs (sauropods) near the S. mirabilis fossils. In fact, all those bones had been buried in river sediment. This indicated that S. mirabilis and the other dinosaurs lived in close proximity, in an inland forested habitat that had a network of rivers. Therefore, the researchers think S. mirabilis hunted for fish in shallow water.

Sereno commented:

I envision this dinosaur as a kind of ‘hell heron’ that had no problem wading on its sturdy legs into two meters of water but probably spent most of its time stalking shallower traps for the many large fish of the day.

Artist’s illustration of a pair of Spinosaurus mirabilis fighting over the carcass of an ancient fish on the bank of a river in an inland forest, about 95 million years ago. Image via Dani Navarro/ University of Chicago. Used with permission.

Bottom line: Scientists discovered a previously unknown 95-million-year-old spinosaur species, Spinosaurus mirabilis, in Niger, Africa, which had a tall crest on its head.

Source: Scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation

Via University of Chicago

Read more: The most exciting dinosaur discoveries of 2025

The post Spectacular new Spinosaurus found in Niger, Africa first appeared on EarthSky.

from EarthSky https://ift.tt/svqOBXD

Artist’s depiction of a fearsome-looking Spinosaurus mirabilis standing at the river’s edge. This newly discovered species, one of the last spinosaurid species before they went extinct, lived 95 million years ago in present-day Niger, Africa. Image via Dani Navarro/ University of Chicago. Used with permission.

• Scientists discovered a new dinosaur species, Spinosaurus mirabilis, in the Sahara Desert of Niger.
• The new species had a tall, scimitar-shaped head crest and lived about 95 million years ago, hunting fish in rivers.
• This discovery suggests spinosaurs might have lived inland in forested river habitats, not just near the coast.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

Newly discovered dinosaur had an eye-catching head crest

Spinosaurs were large dinosaurs that lived about 100 to 94 million years ago. They were notable for distinctive projections on their backs that looked like sails. Scientists first discovered this dinosaur genus in 1915, and for a long time, there was just one recognized species. But on February 19, 2026, a research team led by Paul Sereno, a paleontologist at the University of Chicago, said they’ve discovered a new spinosaur species in the Central Sahara Desert. They named it Spinosaurus mirabilis – mirabilis means “astonishing” in Latin – because it had an unusual, tall crest on its head.

Sereno said:

This find was so sudden and amazing, it was really emotional for our team. I’ll forever cherish the moment in camp when we crowded around a laptop to look at the new species for the first time, after one member of our team generated 3D digital models of the bones we found to assemble the skull, on solar power in the middle of the Sahara. That’s when the significance of the discovery really registered.

Sereno and his colleagues published their findings in the peer-reviewed journal Nature on February 19, 2026.

University of Chicago paleontologist Paul Sereno led the team that excavated and identified the new spinosaur, Spinosaurus mirabilis. He poses here with the skull cast. Image via Keith Ladzinski/ University of Chicago. Used with permission.

This Spinosaurus was a dramatic-looking creature!

Spinosaurs lived 100 to 94 million years ago in present-day Africa. Until now, researchers only recognized one species, Spinosaurus aegyptiacus. Scientists found those fossils at sites that were once coastal habitats when the animals were alive. Therefore, they thought these dinosaurs could be aquatic or semi-aquatic, capable of hunting for fish in the sea. But the degree to which they took to the water was not clear.

These dinosaurs had upward-projecting bones from their backs, creating stunning sail-like features. The animals likely used the sail for display, and it may have even regulated body temperature. In addition, S. aegyptiacus had a long skull similar to crocodiles, optimized for catching fish.

These unusual dinosaurs became extinct about 94 million years ago, due to a rapid rise in sea level and climate change.

A video of Paul Sereno and his team in the field, in Niger, in 2022. Provided by the University of Chicago.

Finding a new Spinosaurus in Niger

In 2019, a local man in the Republic of Niger led Sereno and his team to a site called Jenguebi that had large fossil bones. Due to the long journey back to camp, the team only had time to grab a few fossils, including teeth and jawbones. But they did not yet know it was a new dinosaur species.

In 2022, Sereno returned to Jenguebi with a larger team. During that expedition, they found more fossils there, as well as many more at a site called Iguidi. In all, they were able to collect incomplete skeletons from several individuals, all of them immature spinosaurs that had not reached adulthood.

He said:

The local people we work with are my lifelong friends, now including the man who led us to Jenguebi and the astonishing spinosaur. They understand the importance of what we’re doing together, for science and for their country.

Dan Vidal, a member of Sereno’s team, with Abdoul Nasser, a guide who led them to the Jenguebi fossil site in 2019. There, they found the first Spinosaurus mirabilis fossils. Image via Alhadji Akamaya/ University of Chicago. Used with permission.

Spinosaurus mirabilis

During the 2022 expedition, as they examined their finds, the team realized they had discovered a species new to science. This spinosaur had an unusually tall head crest. Also, the teeth arrangement in its jaw was a bit different from that of S. aegyptiacus.

The new spinosaur had a crest at the top of the skull that the researchers described as scimitar-shaped. That’s a short sword with a curved blade that becomes broader at its tip. In addition, internal vascular canals and the surface texture of the crest suggested it was once coated in keratin. That’s a fibrous protein found in hair, nails and horns. Moreover, they speculated this crest might have been brightly colored.

Ana Lázaro, a member of Sereno’s 2022 expedition to Niger, holds the most complete head crest found for Spinosaurus mirabilis. Image via Alvaro Simarro/ University of Chicago. Used with permission.

S. mirabilis’ jaws were quite formidable, similar to those of S. aegyptiacus. It had interdigitating upper and lower tooth rows. In other words, the teeth in the lower jaw extended outward. Meanwhile, the lower jaw teeth interlocked with those in the upper jaw. This is a feature that exists in many fish-eating animals in the fossil record, such as ichthyosaurs, pterosaurs and some crocodiles.

These are 2 skull casts of spinosaurs. At the top is the newly discovered Spinosaurus mirabilis, and below it is the previously known Spinosaurus aegyptiacus from North Africa. Image via Keith Ladzinski/ University of Chicago. Used with permission.

The bones they collected all came from subadult animals. Therefore, it’s hard to determine the size of an adult S. mirabilis. However, they were able to establish that the individual initially used to describe the species – the holotype – was about 26 feet (8 meters) long.

New clues to how spinosaurs lived

The previously known S. aegyptiacus was found in North Africa, at locations that were once coastal habitat when the animals were alive. Scientists wondered if spinosaurs were fully aquatic and able to dive for prey. But there was considerable debate about it.

However, this new discovery paints a different picture of how spinosaurs may have lived. About 95 million years ago, Jenguebi was 310 miles (500 km) from the coastline. Iguidi was even further away, about 620 miles (1,000 km). That’s pretty far inland from the ocean.

Moreover, the scientists also found fossils from two long-necked dinosaurs (sauropods) near the S. mirabilis fossils. In fact, all those bones had been buried in river sediment. This indicated that S. mirabilis and the other dinosaurs lived in close proximity, in an inland forested habitat that had a network of rivers. Therefore, the researchers think S. mirabilis hunted for fish in shallow water.

Sereno commented:

I envision this dinosaur as a kind of ‘hell heron’ that had no problem wading on its sturdy legs into two meters of water but probably spent most of its time stalking shallower traps for the many large fish of the day.

Artist’s illustration of a pair of Spinosaurus mirabilis fighting over the carcass of an ancient fish on the bank of a river in an inland forest, about 95 million years ago. Image via Dani Navarro/ University of Chicago. Used with permission.

Bottom line: Scientists discovered a previously unknown 95-million-year-old spinosaur species, Spinosaurus mirabilis, in Niger, Africa, which had a tall crest on its head.

Source: Scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation

Via University of Chicago

Read more: The most exciting dinosaur discoveries of 2025

The post Spectacular new Spinosaurus found in Niger, Africa first appeared on EarthSky.

from EarthSky https://ift.tt/svqOBXD

Castor – the twin star – is 6 stars in one

From a Northern Hemisphere location, face generally northward to find the Big Dipper asterism in the constellation Ursa Major. Look mid-evening or later in February, earlier in March. Draw an imaginary line diagonally through the bowl of the Big Dipper, from the star Megrez through the star Merak. You are going in the direction opposite of the Big Dipper’s handle. You’ll see 2 stars noticeable for being bright and close together: Castor and Pollux.

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Castor, the less-bright Twin

Castor, in the constellation Gemini the Twins, shines with a bright white light. That’s in contrast to the golden glow of its brother star in Gemini, Pollux. Despite being labeled as twins, Castor and Pollux are not gravitationally bound. Yet Castor is gravitationally bound into a multiple system of its own. In fact, it’s six stars in one!

Castor’s other designation is Alpha Geminorum. And usually an alpha star is the brightest in its constellation. But Castor is 2nd-brightest in Gemini, however, after Pollux (or Beta Geminorum).

Castor is about 51 light-years away. Meanwhile, Pollux is only 34 light-years away. So Pollux is closer to us. And their distances also show Pollux and Castor aren’t gravitationally bound, but only near each other along our line of sight.

And in 2026 Jupiter is nearby

The constellation Gemini the Twins is high in the February evening sky. And in February 2026 – and for the next few months – the bright planet Jupiter is near the 2 brightest stars of Gemini. These stars are golden Pollux and white Castor. Pollux is the slightly brighter one. But Jupiter outshines them both! Chart via EarthSky.

Castor is a complex star system

Castor is three pairs of binary stars – six stars in all – in a complex dance around a common center of mass.

Even a fairly small telescope will show Castor as two stars. In addition, you might glimpse a much-fainter star nearby, too; it’s also part of the Castor system. Each of these three stars – called Castor A, B and C – is also double. Telescopes don’t show them as double directly. But a spectroscope – which splits starlight into its component colors – reveals each of the three stars as double.

The two larger visible components in the Castor system are hot A-type stars. On the other hand, the smaller components are cool, M-type red dwarf stars.

Altogether, the mass of all six stars is, very roughly, about six times that of our sun.

The star Castor is a system of six gravitationally bound stars. There are 3 pairs of stars, each pair orbiting their common center of mass. The Castor A pair and the Castor B pair mutually orbit their common center of mass. These 4 stars and the Castor C pair orbit their common center of mass. Image via NASA/ JPL-Caltech/ Nicholas Beeson/ Wikimedia Commons.

Visualizing the separation of the stars

This figure shows the orbit hierarchy of Castor’s star system, along with each of their orbital periods and separation from each other. Castor Aa and Ba orbit each other, and each have their own stellar companion, Ab and Bb, respectively. Castor C, composed of the binary pair Ca and Cb, is farther away and orbits around Castor Aa/Ab and Ba/Bb. Image via Wikipedia.

Another way to find the Twins

Northern Hemisphere skywatchers can find Castor and Pollux using the Big Dipper as a guide, as shown on the chart at the top of this post. And, from anywhere on the globe, you can use the constellation Orion the Hunter (see chart below) to find the the twins.

Star-hop from Orion to the “twin” stars Castor and Pollux by drawing an imaginary line from Orion’s bright star Rigel through its bright star Betelgeuse. Then, extend this line about three times the distance between these two stars.

This line will point to Castor and Pollux.

Want the view from your specific location at a specific time of year? Try Stellarium.

A line from Rigel to Betelgeuse in the easy-to-see constellation Orion points to Castor and Pollux.

Greek mythology of Castor and Pollux

The reason for the name Castor is unclear. There appears to be no specific connection with a beaver, which is what the word means in Latin.

However, there is much mythology associated with these two stars, typically in conjunction with each other. Generally in mythology they are twins. In Greek mythology, Pollux is immortal, the son of Zeus, and Castor is mortal, the son of King Tyndareus of Sparta.

So, they were really half-brothers rather than true twins, with a common mother in Queen Leda. Their conception and birth was a complicated and unlikely affair, though, with their mother succumbing to both Zeus (disguised as a swan) and King Tyndareus on the same night. The resulting birth gave us not only Castor and Pollux but also their sister, Helen of Troy.

According to legend, Castor and Pollux sailed among the Argonauts with Jason in search of the Golden Fleece. By most accounts, Castor was killed in battle and Pollux could not bear to live without him. Zeus allowed Pollux to spend every other day in Olympus with the gods, and the rest of the time in the underworld with his brother.

To honor the brothers’ devotion, Zeus placed their constellation in the sky as a remembrance.

Castor and Pollux, the Gemini twins, as depicted in Urania’s Mirror, a set of constellation cards from around 1825. Image via Adam Cuerdon/ Wikipedia.

Other stories surrounding the stars

While in many cultures they were the Twins, in India they were the Horsemen, and in Phoenicia they were the two gazelles or two kid-goats. Likewise, early Christians sometimes called them David and Jonathan, while the early Arabian stargazers knew them as two peacocks.

Perhaps the most unexpected interpretation for the Twins (along with the rest of Gemini) was as a “pile of bricks” as reported by Richard Hinckley Allen. Apparently the pile of bricks stood for the foundation of Rome, and in that context Castor and Pollux were associated with Romulus and Remus, the city’s legendary twin founders.

Additionally, the twin stars represent Yin and Yang, the contrasts and complements of life, in Chinese culture. In all of these cases, they represent two of something.

Indeed, you’ll see why if you find these two stars in the night sky.

Castor’s position is RA: 07h 34m 36s, Dec: +31° 53′ 19″

Bottom line: The star Castor, which appears as one of two bright stars in the constellation Gemini the Twins, is actually a six-star system.

The post Castor – the twin star – is 6 stars in one first appeared on EarthSky.

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From a Northern Hemisphere location, face generally northward to find the Big Dipper asterism in the constellation Ursa Major. Look mid-evening or later in February, earlier in March. Draw an imaginary line diagonally through the bowl of the Big Dipper, from the star Megrez through the star Merak. You are going in the direction opposite of the Big Dipper’s handle. You’ll see 2 stars noticeable for being bright and close together: Castor and Pollux.

Don’t miss the next unmissable night sky event. Sign up for our free newsletter for daily night sky updates, as well as the latest science news.

Castor, the less-bright Twin

Castor, in the constellation Gemini the Twins, shines with a bright white light. That’s in contrast to the golden glow of its brother star in Gemini, Pollux. Despite being labeled as twins, Castor and Pollux are not gravitationally bound. Yet Castor is gravitationally bound into a multiple system of its own. In fact, it’s six stars in one!

Castor’s other designation is Alpha Geminorum. And usually an alpha star is the brightest in its constellation. But Castor is 2nd-brightest in Gemini, however, after Pollux (or Beta Geminorum).

Castor is about 51 light-years away. Meanwhile, Pollux is only 34 light-years away. So Pollux is closer to us. And their distances also show Pollux and Castor aren’t gravitationally bound, but only near each other along our line of sight.

And in 2026 Jupiter is nearby

The constellation Gemini the Twins is high in the February evening sky. And in February 2026 – and for the next few months – the bright planet Jupiter is near the 2 brightest stars of Gemini. These stars are golden Pollux and white Castor. Pollux is the slightly brighter one. But Jupiter outshines them both! Chart via EarthSky.

Castor is a complex star system

Castor is three pairs of binary stars – six stars in all – in a complex dance around a common center of mass.

Even a fairly small telescope will show Castor as two stars. In addition, you might glimpse a much-fainter star nearby, too; it’s also part of the Castor system. Each of these three stars – called Castor A, B and C – is also double. Telescopes don’t show them as double directly. But a spectroscope – which splits starlight into its component colors – reveals each of the three stars as double.

The two larger visible components in the Castor system are hot A-type stars. On the other hand, the smaller components are cool, M-type red dwarf stars.

Altogether, the mass of all six stars is, very roughly, about six times that of our sun.

The star Castor is a system of six gravitationally bound stars. There are 3 pairs of stars, each pair orbiting their common center of mass. The Castor A pair and the Castor B pair mutually orbit their common center of mass. These 4 stars and the Castor C pair orbit their common center of mass. Image via NASA/ JPL-Caltech/ Nicholas Beeson/ Wikimedia Commons.

Visualizing the separation of the stars

This figure shows the orbit hierarchy of Castor’s star system, along with each of their orbital periods and separation from each other. Castor Aa and Ba orbit each other, and each have their own stellar companion, Ab and Bb, respectively. Castor C, composed of the binary pair Ca and Cb, is farther away and orbits around Castor Aa/Ab and Ba/Bb. Image via Wikipedia.

Another way to find the Twins

Northern Hemisphere skywatchers can find Castor and Pollux using the Big Dipper as a guide, as shown on the chart at the top of this post. And, from anywhere on the globe, you can use the constellation Orion the Hunter (see chart below) to find the the twins.

Star-hop from Orion to the “twin” stars Castor and Pollux by drawing an imaginary line from Orion’s bright star Rigel through its bright star Betelgeuse. Then, extend this line about three times the distance between these two stars.

This line will point to Castor and Pollux.

Want the view from your specific location at a specific time of year? Try Stellarium.

A line from Rigel to Betelgeuse in the easy-to-see constellation Orion points to Castor and Pollux.

Greek mythology of Castor and Pollux

The reason for the name Castor is unclear. There appears to be no specific connection with a beaver, which is what the word means in Latin.

However, there is much mythology associated with these two stars, typically in conjunction with each other. Generally in mythology they are twins. In Greek mythology, Pollux is immortal, the son of Zeus, and Castor is mortal, the son of King Tyndareus of Sparta.

So, they were really half-brothers rather than true twins, with a common mother in Queen Leda. Their conception and birth was a complicated and unlikely affair, though, with their mother succumbing to both Zeus (disguised as a swan) and King Tyndareus on the same night. The resulting birth gave us not only Castor and Pollux but also their sister, Helen of Troy.

According to legend, Castor and Pollux sailed among the Argonauts with Jason in search of the Golden Fleece. By most accounts, Castor was killed in battle and Pollux could not bear to live without him. Zeus allowed Pollux to spend every other day in Olympus with the gods, and the rest of the time in the underworld with his brother.

To honor the brothers’ devotion, Zeus placed their constellation in the sky as a remembrance.

Castor and Pollux, the Gemini twins, as depicted in Urania’s Mirror, a set of constellation cards from around 1825. Image via Adam Cuerdon/ Wikipedia.

Other stories surrounding the stars

While in many cultures they were the Twins, in India they were the Horsemen, and in Phoenicia they were the two gazelles or two kid-goats. Likewise, early Christians sometimes called them David and Jonathan, while the early Arabian stargazers knew them as two peacocks.

Perhaps the most unexpected interpretation for the Twins (along with the rest of Gemini) was as a “pile of bricks” as reported by Richard Hinckley Allen. Apparently the pile of bricks stood for the foundation of Rome, and in that context Castor and Pollux were associated with Romulus and Remus, the city’s legendary twin founders.

Additionally, the twin stars represent Yin and Yang, the contrasts and complements of life, in Chinese culture. In all of these cases, they represent two of something.

Indeed, you’ll see why if you find these two stars in the night sky.

Castor’s position is RA: 07h 34m 36s, Dec: +31° 53′ 19″

Bottom line: The star Castor, which appears as one of two bright stars in the constellation Gemini the Twins, is actually a six-star system.

The post Castor – the twin star – is 6 stars in one first appeared on EarthSky.

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Meet Pollux: The brighter twin star of Gemini

Draw an imaginary line from 2 bright stars in the easy-to-see constellation Orion the Hunter to star-hop to the “twin” stars Castor and Pollux. The line goes from Orion’s bright star Rigel through its bright star Betelgeuse and extends about 3 times the distance between them. Castor and Pollux are noticeable for being bright and close together on the sky’s dome. Pollux is brighter than Castor. Chart via EarthSky.

Don’t miss the next unmissable night sky event. Sign up for our free newsletter for daily night sky updates, as well as the latest science news.

Like a pair of twins, two stars shine prominently in the evening skies in February each year. They are Pollux and Castor in the constellation Gemini the Twins. Pollux, also known as Beta Geminorum, is slightly brighter than Castor. It shines with a golden glow while Castor appears whiter. Pollux is the 17th brightest star in Earth’s night sky.

Pollux and Castor are noticeable for being bright and close together. That’s likely how the early stargazers came to identify them as twins. And it’ll be helpful to you, too, when you’re trying to spot these two stars in our night sky.

Pollux is relatively close to us at 34 light-years away.

You can use the easy-to-see constellation Orion to find Castor and Pollux, as shown on the chart above.

And in 2026, bright Jupiter is nearby

The constellation Gemini the Twins is high in the February evening sky. And in February 2026 – and for the next few months – the bright planet Jupiter is near the 2 brightest stars of Gemini. These stars are golden Pollux and white Castor. Pollux is the slightly brighter one. But Jupiter outshines them both! Chart via EarthSky.

Another way to find them

There are two good ways to find Pollux and Castor. From a Northern Hemisphere location face generally northward to find the Big Dipper asterism in the constellation Ursa Major. Draw an imaginary line diagonally through the bowl of the Big Dipper, from the star Megrez through the star Merak. You are going in the direction opposite to the Big Dipper’s handle.

This line will point to Castor and Pollux.

Want the view from your specific location at a specific time of year? Try Stellarium.

Draw an imaginary line diagonally through the Big Dipper” rel=”noopener” target=”_blank”>Big Dipper’s bowl to locate Castor and Pollux.

Science of Pollux

Pollux is classified as a K0 IIIb star. The K0 means that it is somewhat cooler than the sun, with a surface color that is a light yellowish orange. Keep in mind that when you look at a star, its color depends significantly on the sensitivity of your eyes, and that color is difficult to discern for most point sources.

Pollux is just under two times the mass of our sun. It’s almost nine times the diameter of our sun. And it’s about 30 times the sun’s brightness in visible light.

Pollux also pumps out a good bit of energy in non-visible infrared radiation. With all forms of radiation counted, Pollux is about 43 times more energetic than our sun.

A large planet, at least two times the mass of Jupiter, was confirmed for Pollux in 2006. The International Astronomical Union announced a proper name for this planet in 2015: Thestias. At 34 light-years away, Thestias is one of the nearest of the more than 6,000 known exoplanets discovered so far.

Thestias moves around Pollux with a period of about 590 Earth days, which is reminiscent of Mars’ orbital period of 687 days. Thestias moves in a nearly circular orbit around its star.

Artist’s concept of the size difference between Pollux and the sun. Image via Omnidoom 999/ Wikimedia Commons.

Why Pollux is Beta

As mentioned above, Pollux is also known as Beta Geminorum. The Greek letter Beta is normally reserved for the 2nd-brightest star in a constellation. But Pollux is brighter than its brother star Castor, which is Gemini’s Alpha star. Being so close together in the sky, Castor and Pollux are easy to compare. If you look, you’ll agree. Pollux is brighter.

It’s possible that one or both stars have altered in brightness since German astronomer Johann Bayer assigned the designation about 300 years ago. Or maybe Bayer sometimes labeled stars in their order of rising times? Castor rises earlier than Pollux as seen from Bayer’s location in Germany. But there’s a geographical dependency here. From some locations south of the equator, Pollux rises first.

Mythology of Pollux and Castor

There is much mythology associated with these two stars, typically only in conjunction with each other. Generally in mythology they are twins. In Greek mythology, Pollux is immortal, the son of Zeus, and Castor is mortal, the son of King Tyndareus of Sparta.

So they were really half-brothers rather than true twins, with a common mother in Queen Leda. Their conception and birth was a complicated and unlikely affair, though, with their mother succumbing to both Zeus (disguised as a swan) and King Tyndareus on the same night. The resulting birth gave us not only Castor and Pollux, but also their sister, Helen of Troy.

Castor and Pollux are later said to have sailed among the Argonauts with Jason in search of the Golden Fleece. By most accounts, Castor was killed in battle and Pollux could not bear to live without him. Pollux begged Zeus to let him die too. Zeus could not grant the gift quite as asked, since Pollux was a god’s son and therefore immortal. But Zeus decreed that Pollux would spend every other day in Olympus with the gods, and the rest of the time in the underworld with his brother.

To honor the brothers’ devotion, Zeus placed their constellation in the sky as a remembrance.

The twin stars in other cultures

While in many cultures they were the Twins, in India they were the Horsemen, and in Phoenicia they were the two gazelles or two kid-goats. Early Christians sometimes called them David and Jonathan, while the early Arabian stargazers knew them as two peacocks.

Perhaps the most unexpected interpretation for the twins (along with the rest of Gemini) was as a “pile of bricks” as reported by Richard Hinckley Allen. Apparently the pile of bricks stood for the foundation of Rome, and in that context Castor and Pollux were associated with Romulus and Remus, the city’s legendary twin founders.

It’s said that in China they were associated with Yin and Yang, the contrasts and complements of life. In all of these cases, they represent two of something.

You’ll see why if you find these two stars in the night sky.

Pollux’s position is RA: 7h 45m 20s, dec: +28° 01′ 35″.

Castor and Pollux, the Gemini twins, as depicted in Urania’s Mirror, a set of constellation cards from around 1825. Image via Adam Cuerdon/ Wikipedia.

Bottom line: Pollux, aka Beta Geminorum, is the slightly brighter “twin” of Castor in the constellation Gemini the Twins.

The post Meet Pollux: The brighter twin star of Gemini first appeared on EarthSky.

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Draw an imaginary line from 2 bright stars in the easy-to-see constellation Orion the Hunter to star-hop to the “twin” stars Castor and Pollux. The line goes from Orion’s bright star Rigel through its bright star Betelgeuse and extends about 3 times the distance between them. Castor and Pollux are noticeable for being bright and close together on the sky’s dome. Pollux is brighter than Castor. Chart via EarthSky.

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Like a pair of twins, two stars shine prominently in the evening skies in February each year. They are Pollux and Castor in the constellation Gemini the Twins. Pollux, also known as Beta Geminorum, is slightly brighter than Castor. It shines with a golden glow while Castor appears whiter. Pollux is the 17th brightest star in Earth’s night sky.

Pollux and Castor are noticeable for being bright and close together. That’s likely how the early stargazers came to identify them as twins. And it’ll be helpful to you, too, when you’re trying to spot these two stars in our night sky.

Pollux is relatively close to us at 34 light-years away.

You can use the easy-to-see constellation Orion to find Castor and Pollux, as shown on the chart above.

And in 2026, bright Jupiter is nearby

The constellation Gemini the Twins is high in the February evening sky. And in February 2026 – and for the next few months – the bright planet Jupiter is near the 2 brightest stars of Gemini. These stars are golden Pollux and white Castor. Pollux is the slightly brighter one. But Jupiter outshines them both! Chart via EarthSky.

Another way to find them

There are two good ways to find Pollux and Castor. From a Northern Hemisphere location face generally northward to find the Big Dipper asterism in the constellation Ursa Major. Draw an imaginary line diagonally through the bowl of the Big Dipper, from the star Megrez through the star Merak. You are going in the direction opposite to the Big Dipper’s handle.

This line will point to Castor and Pollux.

Want the view from your specific location at a specific time of year? Try Stellarium.

Draw an imaginary line diagonally through the Big Dipper” rel=”noopener” target=”_blank”>Big Dipper’s bowl to locate Castor and Pollux.

Science of Pollux

Pollux is classified as a K0 IIIb star. The K0 means that it is somewhat cooler than the sun, with a surface color that is a light yellowish orange. Keep in mind that when you look at a star, its color depends significantly on the sensitivity of your eyes, and that color is difficult to discern for most point sources.

Pollux is just under two times the mass of our sun. It’s almost nine times the diameter of our sun. And it’s about 30 times the sun’s brightness in visible light.

Pollux also pumps out a good bit of energy in non-visible infrared radiation. With all forms of radiation counted, Pollux is about 43 times more energetic than our sun.

A large planet, at least two times the mass of Jupiter, was confirmed for Pollux in 2006. The International Astronomical Union announced a proper name for this planet in 2015: Thestias. At 34 light-years away, Thestias is one of the nearest of the more than 6,000 known exoplanets discovered so far.

Thestias moves around Pollux with a period of about 590 Earth days, which is reminiscent of Mars’ orbital period of 687 days. Thestias moves in a nearly circular orbit around its star.

Artist’s concept of the size difference between Pollux and the sun. Image via Omnidoom 999/ Wikimedia Commons.

Why Pollux is Beta

As mentioned above, Pollux is also known as Beta Geminorum. The Greek letter Beta is normally reserved for the 2nd-brightest star in a constellation. But Pollux is brighter than its brother star Castor, which is Gemini’s Alpha star. Being so close together in the sky, Castor and Pollux are easy to compare. If you look, you’ll agree. Pollux is brighter.

It’s possible that one or both stars have altered in brightness since German astronomer Johann Bayer assigned the designation about 300 years ago. Or maybe Bayer sometimes labeled stars in their order of rising times? Castor rises earlier than Pollux as seen from Bayer’s location in Germany. But there’s a geographical dependency here. From some locations south of the equator, Pollux rises first.

Mythology of Pollux and Castor

There is much mythology associated with these two stars, typically only in conjunction with each other. Generally in mythology they are twins. In Greek mythology, Pollux is immortal, the son of Zeus, and Castor is mortal, the son of King Tyndareus of Sparta.

So they were really half-brothers rather than true twins, with a common mother in Queen Leda. Their conception and birth was a complicated and unlikely affair, though, with their mother succumbing to both Zeus (disguised as a swan) and King Tyndareus on the same night. The resulting birth gave us not only Castor and Pollux, but also their sister, Helen of Troy.

Castor and Pollux are later said to have sailed among the Argonauts with Jason in search of the Golden Fleece. By most accounts, Castor was killed in battle and Pollux could not bear to live without him. Pollux begged Zeus to let him die too. Zeus could not grant the gift quite as asked, since Pollux was a god’s son and therefore immortal. But Zeus decreed that Pollux would spend every other day in Olympus with the gods, and the rest of the time in the underworld with his brother.

To honor the brothers’ devotion, Zeus placed their constellation in the sky as a remembrance.

The twin stars in other cultures

While in many cultures they were the Twins, in India they were the Horsemen, and in Phoenicia they were the two gazelles or two kid-goats. Early Christians sometimes called them David and Jonathan, while the early Arabian stargazers knew them as two peacocks.

Perhaps the most unexpected interpretation for the twins (along with the rest of Gemini) was as a “pile of bricks” as reported by Richard Hinckley Allen. Apparently the pile of bricks stood for the foundation of Rome, and in that context Castor and Pollux were associated with Romulus and Remus, the city’s legendary twin founders.

It’s said that in China they were associated with Yin and Yang, the contrasts and complements of life. In all of these cases, they represent two of something.

You’ll see why if you find these two stars in the night sky.

Pollux’s position is RA: 7h 45m 20s, dec: +28° 01′ 35″.

Castor and Pollux, the Gemini twins, as depicted in Urania’s Mirror, a set of constellation cards from around 1825. Image via Adam Cuerdon/ Wikipedia.

Bottom line: Pollux, aka Beta Geminorum, is the slightly brighter “twin” of Castor in the constellation Gemini the Twins.

The post Meet Pollux: The brighter twin star of Gemini first appeared on EarthSky.

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February 28 planet parade: Here’s what you can really see

Watch EarthSky’s Deborah Byrd and Marcy Curran discuss the February 28 planet parade and what you can see in the night sky.

February 28 planet parade: Here’s what you can really see

The internet has been full of memes and claims that there will be a spectacular lineup of six visible planets on February 28. But, as is often the case with online chatter, some of it is not accurate. So here’s what you can really see in the sky on the evening of February 28.

As soon as the sun sets, the first thing you’ll probably notice in the sky is the moon. It will already have risen in the east and it will be big and bright, at almost 93% full. It’s just a few days away from full moon, on March 3, when there will be a total lunar eclipse. But on the evening of February 28, it’s not yet full, and there’s a bright “star” shining higher in the sky above the moon. That star is really the planet Jupiter.

While Jupiter and the moon make a pretty scene, you’ll have to tear your eyes away and look toward the western horizon where the sun has recently set. There you’ll find a cluster of planets that will also soon be setting. Venus is the brightest, but it’s also currently close to the horizon. So it will be competing with the evening glow of twilight.

Mercury is dimmer and a bit north of Venus. Next is Saturn, a bit higher above the horizon. So it will be visible as the sky gets darker. But to see any of these three, you must have a flat horizon with no buildings, trees or other obstructions blocking your view.

So that’s only four planets, and really just one of them is easy to see. There are two other planets in the sky that night as well. Uranus is close to the pretty star cluster known as the Pleiades, while Neptune is not far from Saturn. But both of these planets require optical aid to see.

Star charts for the planetary parade

Why do posts on social media point to February 28? It’s a bit of a mystery, because the planets have been in these same general positions for weeks. Planets don’t move that quickly. Perhaps this date is popular because the moon is at one end of the line of planets, near bright Jupiter.

Check out the charts below to find where the planets are, in case you want to hunt them down yourself. And keep up with where the moon and planets are every night with EarthSky’s visible planets and night sky guide.

As seen from across Earth toward the end of February – about 40 minutes after sunset – the bright planet Jupiter will be in the east. Very low in the west, just above the horizon, is Venus, Mercury and Saturn. Note that these planets lie along the path the sun travels in the daytime (the green line on our chart, or the ecliptic). Chart via EarthSky.

It’s true that there are 6 planets in the sky after sunset in mid-to-late February. But 3 (Venus, Mercury and Saturn) are hiding near the sunset’s glow, and 2 (Uranus and Neptune) require optical aid to see. Yet you can see them if you have patience, persistence, optical aid, a detailed star chart and a location with a clear view to the western horizon. And anyone can spot bright Jupiter, not far from the famous constellation Orion. Chart via EarthSky.

Bottom line: Rumors of a February 28 planet parade are sweeping the internet. Will you be able to see six planets in a line? Get the details here.

Listen to this month’s “Planetary Parade” with NASA’s Chandra

The post February 28 planet parade: Here’s what you can really see first appeared on EarthSky.

from EarthSky https://ift.tt/FUnSD0u

Watch EarthSky’s Deborah Byrd and Marcy Curran discuss the February 28 planet parade and what you can see in the night sky.

February 28 planet parade: Here’s what you can really see

The internet has been full of memes and claims that there will be a spectacular lineup of six visible planets on February 28. But, as is often the case with online chatter, some of it is not accurate. So here’s what you can really see in the sky on the evening of February 28.

As soon as the sun sets, the first thing you’ll probably notice in the sky is the moon. It will already have risen in the east and it will be big and bright, at almost 93% full. It’s just a few days away from full moon, on March 3, when there will be a total lunar eclipse. But on the evening of February 28, it’s not yet full, and there’s a bright “star” shining higher in the sky above the moon. That star is really the planet Jupiter.

While Jupiter and the moon make a pretty scene, you’ll have to tear your eyes away and look toward the western horizon where the sun has recently set. There you’ll find a cluster of planets that will also soon be setting. Venus is the brightest, but it’s also currently close to the horizon. So it will be competing with the evening glow of twilight.

Mercury is dimmer and a bit north of Venus. Next is Saturn, a bit higher above the horizon. So it will be visible as the sky gets darker. But to see any of these three, you must have a flat horizon with no buildings, trees or other obstructions blocking your view.

So that’s only four planets, and really just one of them is easy to see. There are two other planets in the sky that night as well. Uranus is close to the pretty star cluster known as the Pleiades, while Neptune is not far from Saturn. But both of these planets require optical aid to see.

Star charts for the planetary parade

Why do posts on social media point to February 28? It’s a bit of a mystery, because the planets have been in these same general positions for weeks. Planets don’t move that quickly. Perhaps this date is popular because the moon is at one end of the line of planets, near bright Jupiter.

Check out the charts below to find where the planets are, in case you want to hunt them down yourself. And keep up with where the moon and planets are every night with EarthSky’s visible planets and night sky guide.

As seen from across Earth toward the end of February – about 40 minutes after sunset – the bright planet Jupiter will be in the east. Very low in the west, just above the horizon, is Venus, Mercury and Saturn. Note that these planets lie along the path the sun travels in the daytime (the green line on our chart, or the ecliptic). Chart via EarthSky.

It’s true that there are 6 planets in the sky after sunset in mid-to-late February. But 3 (Venus, Mercury and Saturn) are hiding near the sunset’s glow, and 2 (Uranus and Neptune) require optical aid to see. Yet you can see them if you have patience, persistence, optical aid, a detailed star chart and a location with a clear view to the western horizon. And anyone can spot bright Jupiter, not far from the famous constellation Orion. Chart via EarthSky.

Bottom line: Rumors of a February 28 planet parade are sweeping the internet. Will you be able to see six planets in a line? Get the details here.

Listen to this month’s “Planetary Parade” with NASA’s Chandra

The post February 28 planet parade: Here’s what you can really see first appeared on EarthSky.

from EarthSky https://ift.tt/FUnSD0u

What is orbital resonance? A dance between heavenly bodies

Astronomers use the term orbital resonance to describe the way planets can gravitationally affect each other when their orbits line up in a regular way. Here, we see 2 planets in a 2:1 orbital resonance. In other words, for every 2 times the inner planet goes around its star, the outer planet goes around once. Image via Amitchell125/ Wikimedia Commons (CC-BY-SA 4.0).

By Chris Impey, University of Arizona

What is orbital resonance?

Planets orbit their parent stars while separated by enormous distances. In our solar system, planets are like grains of sand in a region the size of a football field. The time that planets take to orbit their suns has no specific relationship to each other.

But sometimes, their orbits display striking patterns. For example, astronomers studying six planets orbiting a star 100 light-years away have found that they orbit their star with an almost rhythmic beat, in perfect synchrony. Each pair of planets completes their orbits in times that are the ratios of whole numbers, allowing the planets to align and exert a gravitational push and pull on the other during their orbit.

This type of gravitational alignment is called orbital resonance, and it’s like a harmony between distant planets.

I’m an astronomer who studies and writes about cosmology. Researchers have discovered over 6,000 exoplanets in the past 30 years, and their extraordinary diversity continues to surprise astronomers.

Harmony of the spheres

Greek mathematician Pythagoras discovered the principles of musical harmony 2,500 years ago by analyzing the sounds of blacksmiths’ hammers and plucked strings.

He believed mathematics was at the heart of the natural world. He proposed that the sun, moon and planets each emit unique hums based on their orbital properties. Pythagoras thought this “music of the spheres” would be imperceptible to the human ear.

Four hundred years ago, Johannes Kepler picked up this idea. He proposed that musical intervals and harmonies described the motions of the six known planets at the time.

To Kepler, the solar system had two basses, Jupiter and Saturn; a tenor, Mars; two altos, Venus and Earth; and a soprano, Mercury. These roles reflected how long it took each planet to orbit the sun, lower speeds for the outer planets and higher speeds for the inner planets.

He called the book he wrote on these mathematical relationships The Harmony of the World. While these ideas have some similarities to the concept of orbital resonance, planets don’t actually make sounds, since sound can’t travel through the vacuum of space.

Orbital resonance

Resonance happens when planets or moons have orbital periods that are ratios of whole numbers. The orbital period is the time taken for a planet to make one complete circuit of the star. So, for example, two planets orbiting a star would be in a 2:1 resonance when one planet takes twice as long as the other to orbit the star. Resonance is seen in only 5% of planetary systems.

Orbital resonance, as seen with Jupiter’s moons, happens when planetary bodies’ orbits line up. For example, Io orbits Jupiter four times in the time it takes Europa to orbit twice and Ganymede to orbit once. Image via WolfmanSF/ Wikimedia Commons (CC0 1.0).

In the solar system, Neptune and Pluto are in a 3:2 resonance. There’s also a triple resonance, 4:2:1, among Jupiter’s three moons Ganymede, Europa and Io. In the time it takes Ganymede to orbit Jupiter, Europa orbits twice and Io orbits four times. Resonances occur naturally, when planets happen to have orbital periods that are the ratio of whole numbers.

The relation to music

Musical intervals describe the relationship between two musical notes. In the musical analogy, important musical intervals based on ratios of frequencies are the fourth, 4:3, the fifth, 3:2, and the octave, 2:1. Anyone who plays the guitar or the piano might recognize these intervals.

Musical intervals can be used to create scales and harmony.

What does orbital resonance do?

Orbital resonances can change how gravity influences two bodies, causing them to speed up, slow down, stabilize on their orbital path and sometimes have their orbits disrupted.

Think of pushing a child on a swing. A planet and a swing both have a natural frequency. Give the child a push that matches the swing motion and they’ll get a boost. They’ll also get a boost if you push them every other time they’re in that position, or every third time. But push them at random times, sometimes with the motion of the swing and sometimes against, and they get no boost.

Orbital resonance can cause planets or asteroids to speed up or start to wobble.

For planets, the boost can keep them continuing on their orbital paths, but it’s much more likely to disrupt their orbits.

Exoplanet resonance

Exoplanets, or planets outside the solar system, show striking examples of resonance, not just between two objects but also between resonant “chains” involving three or more objects.

The star Gliese 876 has three planets with orbit period ratios of 4:2:1, just like Jupiter’s three moons. Kepler 223 has four planets with ratios of 8:6:4:3.

The red dwarf Kepler 80 has five planets with ratios of 9:6:4:3:2, and TOI 178 has six planets, of which five are in a resonant chain with ratios of 18:9:6:4:3.

TRAPPIST-1 is the record holder. It has seven Earth-like planets, two of which might be habitable, with orbit ratios of 24:15:9:6:4:3:2.

The newest example of a resonant chain is the HD 110067 system. It’s about 100 light-years away and has six sub-Neptune planets, a common type of exoplanet, with orbit ratios of 54:36:24:16:12:9. The discovery is interesting because most resonance chains are unstable and disappear over time.

Despite these examples, resonant chains are rare, and only 1% of all planetary systems display them. Astronomers think that planets form in resonance, but small gravitational nudges from passing stars and wandering planets erase the resonance over time. With HD 110067, the resonant chain has survived for billions of years, offering a rare and pristine view of the system as it was when it formed.

Orbit sonification

Astronomers use a technique called sonification to translate complex visual data into sound. It gives people a different way to appreciate the beautiful images from the Hubble Space Telescope, and it has been applied to X-ray data and gravitational waves.

With exoplanets, sonification can convey the mathematical relationships of their orbits. Astronomers at the European Southern Observatory created what they call music of the spheres for the TOI 178 system by associating a sound on a pentatonic scale to each of the five planets.

Music from planetary orbits, created by astronomers at the European Southern Observatory.

A similar musical translation has been done for the TRAPPIST-1 system, with the orbital frequencies scaled up by a factor of 212 million to bring them into audible range.

Astronomers have also created a sonification for the HD 110067 system. People may not agree on whether these renditions sound like actual music, but it’s inspiring to see Pythagoras’ ideas realized after 2,500 years.

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona

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

Bottom line: What is orbital resonance? It’s a precise dance between heavenly bodies when their orbits line up, causing them to have specific synchronicities.

Read more: Four mini-Neptunes orbiting in lock step

The post What is orbital resonance? A dance between heavenly bodies first appeared on EarthSky.

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Astronomers use the term orbital resonance to describe the way planets can gravitationally affect each other when their orbits line up in a regular way. Here, we see 2 planets in a 2:1 orbital resonance. In other words, for every 2 times the inner planet goes around its star, the outer planet goes around once. Image via Amitchell125/ Wikimedia Commons (CC-BY-SA 4.0).

By Chris Impey, University of Arizona

What is orbital resonance?

Planets orbit their parent stars while separated by enormous distances. In our solar system, planets are like grains of sand in a region the size of a football field. The time that planets take to orbit their suns has no specific relationship to each other.

But sometimes, their orbits display striking patterns. For example, astronomers studying six planets orbiting a star 100 light-years away have found that they orbit their star with an almost rhythmic beat, in perfect synchrony. Each pair of planets completes their orbits in times that are the ratios of whole numbers, allowing the planets to align and exert a gravitational push and pull on the other during their orbit.

This type of gravitational alignment is called orbital resonance, and it’s like a harmony between distant planets.

I’m an astronomer who studies and writes about cosmology. Researchers have discovered over 6,000 exoplanets in the past 30 years, and their extraordinary diversity continues to surprise astronomers.

Harmony of the spheres

Greek mathematician Pythagoras discovered the principles of musical harmony 2,500 years ago by analyzing the sounds of blacksmiths’ hammers and plucked strings.

He believed mathematics was at the heart of the natural world. He proposed that the sun, moon and planets each emit unique hums based on their orbital properties. Pythagoras thought this “music of the spheres” would be imperceptible to the human ear.

Four hundred years ago, Johannes Kepler picked up this idea. He proposed that musical intervals and harmonies described the motions of the six known planets at the time.

To Kepler, the solar system had two basses, Jupiter and Saturn; a tenor, Mars; two altos, Venus and Earth; and a soprano, Mercury. These roles reflected how long it took each planet to orbit the sun, lower speeds for the outer planets and higher speeds for the inner planets.

He called the book he wrote on these mathematical relationships The Harmony of the World. While these ideas have some similarities to the concept of orbital resonance, planets don’t actually make sounds, since sound can’t travel through the vacuum of space.

Orbital resonance

Resonance happens when planets or moons have orbital periods that are ratios of whole numbers. The orbital period is the time taken for a planet to make one complete circuit of the star. So, for example, two planets orbiting a star would be in a 2:1 resonance when one planet takes twice as long as the other to orbit the star. Resonance is seen in only 5% of planetary systems.

Orbital resonance, as seen with Jupiter’s moons, happens when planetary bodies’ orbits line up. For example, Io orbits Jupiter four times in the time it takes Europa to orbit twice and Ganymede to orbit once. Image via WolfmanSF/ Wikimedia Commons (CC0 1.0).

In the solar system, Neptune and Pluto are in a 3:2 resonance. There’s also a triple resonance, 4:2:1, among Jupiter’s three moons Ganymede, Europa and Io. In the time it takes Ganymede to orbit Jupiter, Europa orbits twice and Io orbits four times. Resonances occur naturally, when planets happen to have orbital periods that are the ratio of whole numbers.

The relation to music

Musical intervals describe the relationship between two musical notes. In the musical analogy, important musical intervals based on ratios of frequencies are the fourth, 4:3, the fifth, 3:2, and the octave, 2:1. Anyone who plays the guitar or the piano might recognize these intervals.

Musical intervals can be used to create scales and harmony.

What does orbital resonance do?

Orbital resonances can change how gravity influences two bodies, causing them to speed up, slow down, stabilize on their orbital path and sometimes have their orbits disrupted.

Think of pushing a child on a swing. A planet and a swing both have a natural frequency. Give the child a push that matches the swing motion and they’ll get a boost. They’ll also get a boost if you push them every other time they’re in that position, or every third time. But push them at random times, sometimes with the motion of the swing and sometimes against, and they get no boost.

Orbital resonance can cause planets or asteroids to speed up or start to wobble.

For planets, the boost can keep them continuing on their orbital paths, but it’s much more likely to disrupt their orbits.

Exoplanet resonance

Exoplanets, or planets outside the solar system, show striking examples of resonance, not just between two objects but also between resonant “chains” involving three or more objects.

The star Gliese 876 has three planets with orbit period ratios of 4:2:1, just like Jupiter’s three moons. Kepler 223 has four planets with ratios of 8:6:4:3.

The red dwarf Kepler 80 has five planets with ratios of 9:6:4:3:2, and TOI 178 has six planets, of which five are in a resonant chain with ratios of 18:9:6:4:3.

TRAPPIST-1 is the record holder. It has seven Earth-like planets, two of which might be habitable, with orbit ratios of 24:15:9:6:4:3:2.

The newest example of a resonant chain is the HD 110067 system. It’s about 100 light-years away and has six sub-Neptune planets, a common type of exoplanet, with orbit ratios of 54:36:24:16:12:9. The discovery is interesting because most resonance chains are unstable and disappear over time.

Despite these examples, resonant chains are rare, and only 1% of all planetary systems display them. Astronomers think that planets form in resonance, but small gravitational nudges from passing stars and wandering planets erase the resonance over time. With HD 110067, the resonant chain has survived for billions of years, offering a rare and pristine view of the system as it was when it formed.

Orbit sonification

Astronomers use a technique called sonification to translate complex visual data into sound. It gives people a different way to appreciate the beautiful images from the Hubble Space Telescope, and it has been applied to X-ray data and gravitational waves.

With exoplanets, sonification can convey the mathematical relationships of their orbits. Astronomers at the European Southern Observatory created what they call music of the spheres for the TOI 178 system by associating a sound on a pentatonic scale to each of the five planets.

Music from planetary orbits, created by astronomers at the European Southern Observatory.

A similar musical translation has been done for the TRAPPIST-1 system, with the orbital frequencies scaled up by a factor of 212 million to bring them into audible range.

Astronomers have also created a sonification for the HD 110067 system. People may not agree on whether these renditions sound like actual music, but it’s inspiring to see Pythagoras’ ideas realized after 2,500 years.

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona

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

Bottom line: What is orbital resonance? It’s a precise dance between heavenly bodies when their orbits line up, causing them to have specific synchronicities.

Read more: Four mini-Neptunes orbiting in lock step

The post What is orbital resonance? A dance between heavenly bodies first appeared on EarthSky.

from EarthSky https://ift.tt/2bnqDEv

Total lunar eclipse: March 2-3 of the full Worm Moon

A total lunar eclipse of the full Worm Moon will sweep across the Pacific Ocean and western North America on March 2-3, 2026. The Blood Moon will be high in the sky for east Asia on the evening on March 3. East of the International Date Line – in Hawaii – the eclipse starts on the evening of March 2. Half a world away, in North America, we’ll have an early morning eclipse on March 3. We’ll be watching the eclipse as the Blood Moon sinks in the west before dawn. Japan, New Zealand, and most of Australia will see the entire event. From central Asia, the moon will rise with the eclipse already in progress. None of the eclipse will be visible from eastern Europe, Africa or western Asia.

And the next total lunar eclipse will be the total lunar eclipse on the morning of New Year’s Eve in 2028. It’s already being widely called the New Year’s Eve Blood Moon and it’ll occur on December 31, 2028.

Total eclipses can turn the moon a deep shade of red. That’s why you’ll hear this eclipse called a Blood Moon eclipse. The shade of red on the moon will depend mostly on what’s happening Earth’s atmosphere at the moment of the eclipse. How dark red will the March 2026 total lunar eclipse be?

View larger. | Map showing the areas of visibility for the March 3, 2026, total lunar eclipse of the full Worm Moon. Image via Dominic Ford from In-The-Sky.org. Used with permission.

The crest of the full moon occurs at 11:38 UTC on March 3. That’s 5:38 a.m. CST. Also, that morning, at 3:50 a.m. CST on March 3, the moon begins to pass through Earth’s umbral (dark) shadow. It becomes totally eclipsed from 5:04 to 6:03 a.m CST. And the bright star Regulus is nearby. By 7:17 a.m. CST the moon has exited the umbral (lighter) shadow ending the total lunar eclipse. Check details on the eclipse below. Chart via EarthSky.

Eclipse details

Full moon occurs at 11:38 UTC on March 3 (5:38 a.m. CST). That’s 35 minutes after totality begins.
Penumbral eclipse begins at 8:43:58 UTC (2:43 a.m. CST) on March 3.
Partial eclipse begins at 9:49:37 UTC (3:49 a.m. CST) on March 3.
Totality begins (moon engulfed in Earth’s shadow) begins at 11:03:54 UTC (5:03 a.m. CST) on March 3.
Maximum eclipse is at 11:33:40 UTC (5:33 a.m. CST) on March 3.
Totality ends at 12:02:53 UTC (6:02 a.m. CST) on March 3.
Partial eclipse ends at 13:17:26 UTC (7:17 a.m. CST) on March 3.
Penumbral eclipse ends at 14:23:19 UTC (8:23 a.m. CST) on March 3.
Duration of totality is about 59 minutes.
Note: A total lunar eclipse is when the sun, Earth and moon are aligned in space, with Earth in the middle. Earth’s shadow falls on the moon.

Also, lunar eclipses are safe to view with the unaided eye. Binoculars and telescopes – and a dark sky – enhance the view, but aren’t required.

Visit timeanddate.com to get eclipse timings from your location.

At 3:50 a.m. CST on March 3, the moon begins to pass through Earth’s umbral shadow. It becomes totally eclipsed from 5:04 a.m. to 6:03 a.m CST. Can you spot the bright star Regulus near the moon during the eclipse? By 7:17 a.m. CST the moon has exited the umbral shadow ending the total lunar eclipse. And the farther east you live in North America, the less of the eclipse you’ll see, because the moon will set before the entire event is over.

Moon, constellation, Saros

The moment of greatest eclipse takes place 6.5 days after the moon reaches perigee, its closest point from Earth for the month.

At mid-eclipse, the moon is located in the direction of the constellation Leo the Lion.

The Saros catalog describes the periodicity of eclipses. This March 3 total lunar eclipse belongs to Saros 133. It is number 27 of 71 eclipses in the series. All eclipses in this series occur at the moon’s descending node. The moon moves northward with respect to the node with each succeeding eclipse in the series.

The instant of greatest eclipse – when the axis of the Earth’s shadow cone passes closest to the moon’s center – takes place at 11:33 UTC on March 3. The moon will lie at zenith – directly overhead – in the Pacific Ocean.

Also, the duration of totality lasts 59 minutes!

Next eclipse of this eclipse seasons

This total lunar eclipse of March 3, 2026, was preceded two weeks earlier by an annular solar eclipse on February 17, 2026. These eclipses all take place during a single eclipse season.

An eclipse season is an approximate 35-day period during which it’s inevitable for at least two (and possibly three) eclipses to take place. In 2026 we have another eclipse season in August with a total solar eclipse on August 12 and a partial lunar eclipse on August 28.

March full moon is the Worm Moon

The 2026 March full moon is the Worm Moon. All the full moons have popular nicknames. Popular names for the March full moon are Worm Moon, Crow Moon and Sap Moon. The name Worm Moon honors the stirring of earthworms and insect larvae in the slowly warming late winter and early spring soil.

Read more: Full moon names

Visit Sunrise Sunset Calendars to know the moonrise time, remembering to check the moonrise and moonset box.

March full moon is in Leo

The full moon on the night of March 3, 2026, is located in the direction of the constellation Leo the Lion. The moon is roundest on the day when it is full, but the day before and the day after, it appears almost, but not quite, full.

Total lunar eclipse maps and data

• Detailed Lunar Eclipse Figure: eclipse geometry diagram and map of eclipse visibility (key to figure)
• Saros 133 Table: data for all eclipses in the Saros series
• Danjon Scale of Lunar Eclipse Brightness
• Timeanddate.com eclipse map and animation

And the next total lunar eclipse is on December 31, 2028. It’ll be the first of three total lunar eclipses in a row. After the total eclipse on December 31, 2026, there will be one on June 26, 2029, and another one on December 20, 2029.

Bottom line: Overnight on March 2-3, 2026, there will be a total lunar eclipse of the March full Worm Moon visible from across northwest South America, North America, the Pacific Ocean, Australia, Asia, Japan, southeast Asia, China, India, and most of Russia.

Read more: A total lunar eclipse looks red. Why?

EarthSky’s monthly night sky guide: Visible planets and more

The post Total lunar eclipse: March 2-3 of the full Worm Moon first appeared on EarthSky.

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A total lunar eclipse of the full Worm Moon will sweep across the Pacific Ocean and western North America on March 2-3, 2026. The Blood Moon will be high in the sky for east Asia on the evening on March 3. East of the International Date Line – in Hawaii – the eclipse starts on the evening of March 2. Half a world away, in North America, we’ll have an early morning eclipse on March 3. We’ll be watching the eclipse as the Blood Moon sinks in the west before dawn. Japan, New Zealand, and most of Australia will see the entire event. From central Asia, the moon will rise with the eclipse already in progress. None of the eclipse will be visible from eastern Europe, Africa or western Asia.

And the next total lunar eclipse will be the total lunar eclipse on the morning of New Year’s Eve in 2028. It’s already being widely called the New Year’s Eve Blood Moon and it’ll occur on December 31, 2028.

Total eclipses can turn the moon a deep shade of red. That’s why you’ll hear this eclipse called a Blood Moon eclipse. The shade of red on the moon will depend mostly on what’s happening Earth’s atmosphere at the moment of the eclipse. How dark red will the March 2026 total lunar eclipse be?

View larger. | Map showing the areas of visibility for the March 3, 2026, total lunar eclipse of the full Worm Moon. Image via Dominic Ford from In-The-Sky.org. Used with permission.

The crest of the full moon occurs at 11:38 UTC on March 3. That’s 5:38 a.m. CST. Also, that morning, at 3:50 a.m. CST on March 3, the moon begins to pass through Earth’s umbral (dark) shadow. It becomes totally eclipsed from 5:04 to 6:03 a.m CST. And the bright star Regulus is nearby. By 7:17 a.m. CST the moon has exited the umbral (lighter) shadow ending the total lunar eclipse. Check details on the eclipse below. Chart via EarthSky.

Eclipse details

Full moon occurs at 11:38 UTC on March 3 (5:38 a.m. CST). That’s 35 minutes after totality begins.
Penumbral eclipse begins at 8:43:58 UTC (2:43 a.m. CST) on March 3.
Partial eclipse begins at 9:49:37 UTC (3:49 a.m. CST) on March 3.
Totality begins (moon engulfed in Earth’s shadow) begins at 11:03:54 UTC (5:03 a.m. CST) on March 3.
Maximum eclipse is at 11:33:40 UTC (5:33 a.m. CST) on March 3.
Totality ends at 12:02:53 UTC (6:02 a.m. CST) on March 3.
Partial eclipse ends at 13:17:26 UTC (7:17 a.m. CST) on March 3.
Penumbral eclipse ends at 14:23:19 UTC (8:23 a.m. CST) on March 3.
Duration of totality is about 59 minutes.
Note: A total lunar eclipse is when the sun, Earth and moon are aligned in space, with Earth in the middle. Earth’s shadow falls on the moon.

Also, lunar eclipses are safe to view with the unaided eye. Binoculars and telescopes – and a dark sky – enhance the view, but aren’t required.

Visit timeanddate.com to get eclipse timings from your location.

At 3:50 a.m. CST on March 3, the moon begins to pass through Earth’s umbral shadow. It becomes totally eclipsed from 5:04 a.m. to 6:03 a.m CST. Can you spot the bright star Regulus near the moon during the eclipse? By 7:17 a.m. CST the moon has exited the umbral shadow ending the total lunar eclipse. And the farther east you live in North America, the less of the eclipse you’ll see, because the moon will set before the entire event is over.

Moon, constellation, Saros

The moment of greatest eclipse takes place 6.5 days after the moon reaches perigee, its closest point from Earth for the month.

At mid-eclipse, the moon is located in the direction of the constellation Leo the Lion.

The Saros catalog describes the periodicity of eclipses. This March 3 total lunar eclipse belongs to Saros 133. It is number 27 of 71 eclipses in the series. All eclipses in this series occur at the moon’s descending node. The moon moves northward with respect to the node with each succeeding eclipse in the series.

The instant of greatest eclipse – when the axis of the Earth’s shadow cone passes closest to the moon’s center – takes place at 11:33 UTC on March 3. The moon will lie at zenith – directly overhead – in the Pacific Ocean.

Also, the duration of totality lasts 59 minutes!

Next eclipse of this eclipse seasons

This total lunar eclipse of March 3, 2026, was preceded two weeks earlier by an annular solar eclipse on February 17, 2026. These eclipses all take place during a single eclipse season.

An eclipse season is an approximate 35-day period during which it’s inevitable for at least two (and possibly three) eclipses to take place. In 2026 we have another eclipse season in August with a total solar eclipse on August 12 and a partial lunar eclipse on August 28.

March full moon is the Worm Moon

The 2026 March full moon is the Worm Moon. All the full moons have popular nicknames. Popular names for the March full moon are Worm Moon, Crow Moon and Sap Moon. The name Worm Moon honors the stirring of earthworms and insect larvae in the slowly warming late winter and early spring soil.

Read more: Full moon names

Visit Sunrise Sunset Calendars to know the moonrise time, remembering to check the moonrise and moonset box.

March full moon is in Leo

The full moon on the night of March 3, 2026, is located in the direction of the constellation Leo the Lion. The moon is roundest on the day when it is full, but the day before and the day after, it appears almost, but not quite, full.

Total lunar eclipse maps and data

• Detailed Lunar Eclipse Figure: eclipse geometry diagram and map of eclipse visibility (key to figure)
• Saros 133 Table: data for all eclipses in the Saros series
• Danjon Scale of Lunar Eclipse Brightness
• Timeanddate.com eclipse map and animation

And the next total lunar eclipse is on December 31, 2028. It’ll be the first of three total lunar eclipses in a row. After the total eclipse on December 31, 2026, there will be one on June 26, 2029, and another one on December 20, 2029.

Bottom line: Overnight on March 2-3, 2026, there will be a total lunar eclipse of the March full Worm Moon visible from across northwest South America, North America, the Pacific Ocean, Australia, Asia, Japan, southeast Asia, China, India, and most of Russia.

Read more: A total lunar eclipse looks red. Why?

EarthSky’s monthly night sky guide: Visible planets and more

The post Total lunar eclipse: March 2-3 of the full Worm Moon first appeared on EarthSky.

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Why is the snowman shape so common in the Kuiper Belt?

In 2019, NASA’s New Horizons mission flew by Kuiper Belt object 486958 Arrokoth. Arrokoth has a snowman shape – or 2-lobed figure – that is common in our outer solar system. Why is this snowman shape so prevalent? Scientists at Michigan State University said the answer might be surprisingly simple. Image via NASA/ Johns Hopkins Applied Physics Laboratory/ Southwest Research Institute/ National Optical Astronomy Observatory.

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Why is the snowman shape so common in the outer solar system?

The outer region of the solar system is home to a slew of snowman-shaped objects. One famous example is Arrokoth, a member of the Kuiper Belt, which is a region beyond Neptune that contains Pluto and other icy objects such as planetesimals. In fact, one in 10 Kuiper Belt objects is snowman-shaped, or what astronomers call a contact binary. On February 19, 2026, researchers at Michigan State University said the reason for all these snowman-shaped objects might be surprisingly simple.

Lead author Jackson Barnes of Michigan State University (MSU) created computer simulations that show gravitational collapse can naturally produce these snowman-shaped objects. Barnes used MSU’s Institute for Cyber-Enabled Research’s High-Performance Computing Center to create simulations that show the formation of dual-lobed objects doesn’t rely on chance collisions or unusual encounters.

Co-author Seth Jacobson of MSU said:

If we think 10% of planetesimal objects are contact binaries, the process that forms them can’t be rare. Gravitational collapse fits nicely with what we’ve observed.

Our first closeup look at a contact binary was Arrokoth. The New Horizons spacecraft flew past the rocky snowman on New Year’s Day in 2019.

The researchers published their peer-reviewed paper in the journal Monthly Notices of the Royal Astronomical Society on February 19, 2026.

Modeling the collapse process

The simulations needed to find an explanation that allowed the contact binaries to happen fairly regularly. And they needed to assure that these objects could retain their shapes over the years. Other computer models ended up with something that eventually morphed into a single, blob-like shape. Barnes’ simulations allow the snowmen to retain their characteristic shape.

In the early solar system, the sun and planets formed out of a swirling disk of gas and dust. On the outer edges of our solar system were remnants of this disk that didn’t become incorporated into the larger bodies. These Kuiper Belt objects live placid lives in the spacious regions of the solar system’s outskirts. Scientists say few collisions occur here.

In Barnes’ simulations, planetesimals form out of the dusty disk into loose aggregations of material. Gravity can then cause the objects to collapse inward, which can rip the object into two parts that then orbit each other until they are once again pulled into a single snowman-shaped object. In a sparsely populated environment, there’s nothing to knock into the objects and separate them again. The scientists note:

Most binaries aren’t even pocked with craters.

The MSU scientists are now working to create even more accurate modeling of the collapse process.

Watch a simulation of a snowman-shaped object after its collapse into 2 and as it reconnects.

Bottom line: Scientists at MSU have modeled the process of gravitational collapse that they say creates the snowman shape that is so common in the outer solar system.

Source: Direct contact binary planetesimal formation from gravitational collapse

Via Royal Astronomical Society

Read more: A new Earthlike planet in the distant Kuiper Belt?

Rare Kuiper Belt triplet might be one of many

The post Why is the snowman shape so common in the Kuiper Belt? first appeared on EarthSky.

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In 2019, NASA’s New Horizons mission flew by Kuiper Belt object 486958 Arrokoth. Arrokoth has a snowman shape – or 2-lobed figure – that is common in our outer solar system. Why is this snowman shape so prevalent? Scientists at Michigan State University said the answer might be surprisingly simple. Image via NASA/ Johns Hopkins Applied Physics Laboratory/ Southwest Research Institute/ National Optical Astronomy Observatory.

EarthSky’s 2026 lunar calendar is available now. Get yours today! Makes a great gift.

Why is the snowman shape so common in the outer solar system?

The outer region of the solar system is home to a slew of snowman-shaped objects. One famous example is Arrokoth, a member of the Kuiper Belt, which is a region beyond Neptune that contains Pluto and other icy objects such as planetesimals. In fact, one in 10 Kuiper Belt objects is snowman-shaped, or what astronomers call a contact binary. On February 19, 2026, researchers at Michigan State University said the reason for all these snowman-shaped objects might be surprisingly simple.

Lead author Jackson Barnes of Michigan State University (MSU) created computer simulations that show gravitational collapse can naturally produce these snowman-shaped objects. Barnes used MSU’s Institute for Cyber-Enabled Research’s High-Performance Computing Center to create simulations that show the formation of dual-lobed objects doesn’t rely on chance collisions or unusual encounters.

Co-author Seth Jacobson of MSU said:

If we think 10% of planetesimal objects are contact binaries, the process that forms them can’t be rare. Gravitational collapse fits nicely with what we’ve observed.

Our first closeup look at a contact binary was Arrokoth. The New Horizons spacecraft flew past the rocky snowman on New Year’s Day in 2019.

The researchers published their peer-reviewed paper in the journal Monthly Notices of the Royal Astronomical Society on February 19, 2026.

Modeling the collapse process

The simulations needed to find an explanation that allowed the contact binaries to happen fairly regularly. And they needed to assure that these objects could retain their shapes over the years. Other computer models ended up with something that eventually morphed into a single, blob-like shape. Barnes’ simulations allow the snowmen to retain their characteristic shape.

In the early solar system, the sun and planets formed out of a swirling disk of gas and dust. On the outer edges of our solar system were remnants of this disk that didn’t become incorporated into the larger bodies. These Kuiper Belt objects live placid lives in the spacious regions of the solar system’s outskirts. Scientists say few collisions occur here.

In Barnes’ simulations, planetesimals form out of the dusty disk into loose aggregations of material. Gravity can then cause the objects to collapse inward, which can rip the object into two parts that then orbit each other until they are once again pulled into a single snowman-shaped object. In a sparsely populated environment, there’s nothing to knock into the objects and separate them again. The scientists note:

Most binaries aren’t even pocked with craters.

The MSU scientists are now working to create even more accurate modeling of the collapse process.

Watch a simulation of a snowman-shaped object after its collapse into 2 and as it reconnects.

Bottom line: Scientists at MSU have modeled the process of gravitational collapse that they say creates the snowman shape that is so common in the outer solar system.

Source: Direct contact binary planetesimal formation from gravitational collapse

Via Royal Astronomical Society

Read more: A new Earthlike planet in the distant Kuiper Belt?

Rare Kuiper Belt triplet might be one of many

The post Why is the snowman shape so common in the Kuiper Belt? first appeared on EarthSky.

from EarthSky https://ift.tt/lLIUg1d