Star dims for 9 months, likely due to giant ringed object

Artist’s impression of a star dimming due to its light being blocked by a giant ringed planet or possibly a brown dwarf. In this illustration, a super-Jupiter with massive rings in the foreground forms an opaque “saucer” through which some light from the star ASASSN-24fw shines. Scientists also discovered a neighboring red dwarf star during their research. Image via S. Shah et al./ Royal Astronomical Society (CC BY 4.0).

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• A star called ASASSN-24fw dimmed by 97% for more than nine months. It was one of the longest stellar dimming events ever recorded. But why did it get so dim for so long?
• Astronomers think an unseen brown dwarf or super-Jupiter with a huge ring system passed in front of the star, blocking its light.
• The researchers expect the star to dim again in about 42 or 43 years. At that time, astronomers can carry out further analysis to find out more about this fascinating system.

The Royal Astronomical Society published this original story on February 12, 2026. Edits by EarthSky.

Star dims for 9 months, likely due to giant ringed planet

One of the longest stellar dimming events ever observed was likely caused by the gigantic saucer-like rings of either an unseen “super-Jupiter” or a brown dwarf blocking its host star’s light. That’s according to astronomers at the Royal Astronomical Society, who described the new research on the fading star on February 12. 2026. The star, named ASASSN-24fw, sits 3,200 light-years from Earth and is about twice as big as our sun. For decades, astronomers had observed the star as stable, but at the end of 2024 it faded dramatically.

It then remained this way for more than nine months, far longer than is normal for an event like this. The unusual length of the dimming sparked confusion among researchers and prompted speculation as to what could have caused such an “extremely rare” phenomenon.

Now, in a new study published February 12, 2026, in the peer-reviewed Monthly Notices of the Royal Astronomical Society, a team of international researchers propose a solution of the riddle of this mysterious star in the Monoceros constellation.

They think it was most likely a brown dwarf (an object between the size of a star and Jupiter) with Saturn-like rings that caused ASASSN-24fw to dim by about 97%. This ring system is so enormous it extends out about 0.17 astronomical units (AU), comparable to half the distance between our sun and Mercury.

Brown dwarf or super-Jupiter

The two most likely objects responsible for blocking the star’s light are a brown dwarf or super-Jupiter.

Brown dwarfs are mysterious objects. They’re too big to be a planet but also too small to be a star. They lack the mass to keep fusing atoms and blossom into fully fledged suns.

The other option, the researchers said, is a super-Jupiter. These are massive gas giant exoplanets that exceed the mass of Jupiter and bridge the gap between brown dwarfs and planets.

Their findings offer a glimpse into complex planetary-scale structures beyond our solar system. And they pave a new way to study how planets and their rings may form and evolve around other stars.

Unlike typical eclipses, which usually last days or weeks, this dimming continued for nearly 200 days, making it one of the longest ever observed.

Lead author Sarang Shah, a post-doctoral researcher at the Inter-University Centre for Astronomy and Astrophysics (IUCAA), in Pune, India, said:

Various models made by our group show that the most likely explanation for the dimming is a brown dwarf – an object heavier than a planet but lighter than a star – surrounded by a vast and dense ring system. It is orbiting the star at a farther distance with the ring.

Long-lasting dimming events like this are exceptionally uncommon as they require very perfect lineups. The dimming began gradually because the outer parts of the rings are thin, and only became obvious when the denser regions passed in front of the star.

Artist’s impression of ASASSN-24fw after the eclipse is over. Now we can see the star shining unobstructed. And it also has a debris disk, possibly the remnants from a planetary collision. The unseen object with its huge rings is at lower right. A companion red dwarf star is at lower left. Image via S. Shah et al./ Royal Astronomical Society (CC BY 4.0).

Large ring system

Analysis of photometric and spectroscopic studies of the event suggests that the companion object has a mass of more than three times that of Jupiter.

The analysis also shows that ASASSN-24fw itself has a circumstellar environment (possibly remnants from past or ongoing planetary collisions) very near to it, which is unusual for a star of this age (likely more than 1 billion years).

Co-author Jonathan Marshall, an independent post-doctoral researcher affiliated with Academia Sinica, Taiwan, has expertise is in circumstellar material and debris discs. Marshall said:

Large ring systems are expected around massive objects, but they are very difficult to observe directly to determine their characteristics. This rare event allows us to study such a complex system in remarkable detail. In fact, while studying this dimming, we also serendipitously discovered that ASASSN-24fw also has a red dwarf star in its vicinity.

The team of researchers now want to measure the temperature, evolutionary status, chemical composition and age of the star that dimmed. They then hope to obtain more data from the European Southern Observatory’s Very Large Telescope in Chile and the James Webb Space Telescope to better understand the evolution of such systems and relate them to planetary formation theories.

The researchers expect the star to dim again in about 42 or 43 years’ time. At that time, astronomers can carry out further analysis to find out more about this fascinating system.

Bottom line: Astronomers watched a star dim to less than 97% of its brightness for nine months. They believe a giant ringed object blocked the light from our view.

Source: The nature of ASASSN-24fw’s occultation: modelling the event as dimming by optically thick rings around a sub-stellar companion

Via Royal Astronomical Society

The post Star dims for 9 months, likely due to giant ringed object first appeared on EarthSky.

from EarthSky https://ift.tt/bEDz1f9

Artist’s impression of a star dimming due to its light being blocked by a giant ringed planet or possibly a brown dwarf. In this illustration, a super-Jupiter with massive rings in the foreground forms an opaque “saucer” through which some light from the star ASASSN-24fw shines. Scientists also discovered a neighboring red dwarf star during their research. Image via S. Shah et al./ Royal Astronomical Society (CC BY 4.0).

EarthSky’s 2026 lunar calendar shows the moon phase for every day of the year. Get yours today!

• A star called ASASSN-24fw dimmed by 97% for more than nine months. It was one of the longest stellar dimming events ever recorded. But why did it get so dim for so long?
• Astronomers think an unseen brown dwarf or super-Jupiter with a huge ring system passed in front of the star, blocking its light.
• The researchers expect the star to dim again in about 42 or 43 years. At that time, astronomers can carry out further analysis to find out more about this fascinating system.

The Royal Astronomical Society published this original story on February 12, 2026. Edits by EarthSky.

Star dims for 9 months, likely due to giant ringed planet

One of the longest stellar dimming events ever observed was likely caused by the gigantic saucer-like rings of either an unseen “super-Jupiter” or a brown dwarf blocking its host star’s light. That’s according to astronomers at the Royal Astronomical Society, who described the new research on the fading star on February 12. 2026. The star, named ASASSN-24fw, sits 3,200 light-years from Earth and is about twice as big as our sun. For decades, astronomers had observed the star as stable, but at the end of 2024 it faded dramatically.

It then remained this way for more than nine months, far longer than is normal for an event like this. The unusual length of the dimming sparked confusion among researchers and prompted speculation as to what could have caused such an “extremely rare” phenomenon.

Now, in a new study published February 12, 2026, in the peer-reviewed Monthly Notices of the Royal Astronomical Society, a team of international researchers propose a solution of the riddle of this mysterious star in the Monoceros constellation.

They think it was most likely a brown dwarf (an object between the size of a star and Jupiter) with Saturn-like rings that caused ASASSN-24fw to dim by about 97%. This ring system is so enormous it extends out about 0.17 astronomical units (AU), comparable to half the distance between our sun and Mercury.

Brown dwarf or super-Jupiter

The two most likely objects responsible for blocking the star’s light are a brown dwarf or super-Jupiter.

Brown dwarfs are mysterious objects. They’re too big to be a planet but also too small to be a star. They lack the mass to keep fusing atoms and blossom into fully fledged suns.

The other option, the researchers said, is a super-Jupiter. These are massive gas giant exoplanets that exceed the mass of Jupiter and bridge the gap between brown dwarfs and planets.

Their findings offer a glimpse into complex planetary-scale structures beyond our solar system. And they pave a new way to study how planets and their rings may form and evolve around other stars.

Unlike typical eclipses, which usually last days or weeks, this dimming continued for nearly 200 days, making it one of the longest ever observed.

Lead author Sarang Shah, a post-doctoral researcher at the Inter-University Centre for Astronomy and Astrophysics (IUCAA), in Pune, India, said:

Various models made by our group show that the most likely explanation for the dimming is a brown dwarf – an object heavier than a planet but lighter than a star – surrounded by a vast and dense ring system. It is orbiting the star at a farther distance with the ring.

Long-lasting dimming events like this are exceptionally uncommon as they require very perfect lineups. The dimming began gradually because the outer parts of the rings are thin, and only became obvious when the denser regions passed in front of the star.

Artist’s impression of ASASSN-24fw after the eclipse is over. Now we can see the star shining unobstructed. And it also has a debris disk, possibly the remnants from a planetary collision. The unseen object with its huge rings is at lower right. A companion red dwarf star is at lower left. Image via S. Shah et al./ Royal Astronomical Society (CC BY 4.0).

Large ring system

Analysis of photometric and spectroscopic studies of the event suggests that the companion object has a mass of more than three times that of Jupiter.

The analysis also shows that ASASSN-24fw itself has a circumstellar environment (possibly remnants from past or ongoing planetary collisions) very near to it, which is unusual for a star of this age (likely more than 1 billion years).

Co-author Jonathan Marshall, an independent post-doctoral researcher affiliated with Academia Sinica, Taiwan, has expertise is in circumstellar material and debris discs. Marshall said:

Large ring systems are expected around massive objects, but they are very difficult to observe directly to determine their characteristics. This rare event allows us to study such a complex system in remarkable detail. In fact, while studying this dimming, we also serendipitously discovered that ASASSN-24fw also has a red dwarf star in its vicinity.

The team of researchers now want to measure the temperature, evolutionary status, chemical composition and age of the star that dimmed. They then hope to obtain more data from the European Southern Observatory’s Very Large Telescope in Chile and the James Webb Space Telescope to better understand the evolution of such systems and relate them to planetary formation theories.

The researchers expect the star to dim again in about 42 or 43 years’ time. At that time, astronomers can carry out further analysis to find out more about this fascinating system.

Bottom line: Astronomers watched a star dim to less than 97% of its brightness for nine months. They believe a giant ringed object blocked the light from our view.

Source: The nature of ASASSN-24fw’s occultation: modelling the event as dimming by optically thick rings around a sub-stellar companion

Via Royal Astronomical Society

The post Star dims for 9 months, likely due to giant ringed object first appeared on EarthSky.

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New clues to how giant galaxies formed in the early universe

Watch a video explaining how giant galaxies in the early universe might have formed. Video via Max Planck Institute for Radio Astronomy.

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

New clues to how giant galaxies formed in the early universe

For decades, astronomers have puzzled over the galaxies they see in the early universe. They’ve spotted massive galaxies just a few billion years after the Big Bang that consist of old stars and are depleted of the gas needed to form new stars. How are galaxies so close to the beginning of the universe already so evolved? On February 10, 2026, astronomers at the Max Planck Institute in Germany said they found evidence a giant elliptical galaxy may form through the rapid collapse of a young galaxy cluster.

The astronomers focused their study on a protocluster – or a massive collection of young galaxies in the early universe – named SPT2349-56. This protocluster existed just 1.4 billion years after the Big Bang, or when the universe was 10% of its current age.

Lead author Nikolaus Sulzenauer, of the Max Planck Institute for Radio Astronomy at the University of Bonn, said:

In a universe where larger galaxies grow hierarchically through gravitational interactions and mergers of smaller building blocks, some giant ellipticals must have formed completely differently than previously thought. Instead of slowly assembling mass throughout 14 billion years, a massive elliptical galaxy might swiftly emerge in just a few hundred million years. It can form through the collapse and coalescence of a major primordial structure, in the time it takes the sun to orbit around the Milky Way’s center once. We find that the structures with the very highest densities must have decoupled first from the universe’s expansion at only 10% of the current cosmic age, and then rapidly assembled entire protoclusters.

The researchers published their peer-reviewed paper in The Astrophysical Journal on February 10, 2026.

Spotlighting a distant protocluster

The researchers used the radio telescopes ALMA and Atacama Pathfinder Experiment in Chile to analyze the cold gas and dust at the center of the protocluster. They chose the protocluster SPT2349-56 – which lies in the direction of the Southern Hemisphere constellation Phoenix – because it’s one of the earliest clusters of massive galaxies that we’ve seen. Co-author Axel Weiss of the Max Planck Institute said:

SPT2349-56 holds the record for the most vigorous stellar factory.

Co-author Ryley Hill from the University of British Columbia in Canada added:

In the center, we found four tightly-interacting galaxies forging one star every 40 minutes.

In comparison, our own Milky Way forms just three to four stars in a year.

Artist’s impression of the protocluster SPT2349-56. These interacting galaxies are different shapes and sizes. Tidal forces are heating the gas (orange) and tearing it apart. We see SPT2349-56 as it looked only 1.4 billion years after the Big Bang, when the universe was 10% of its current age. Image via N.Sulzenauer/ Max Planck Institute for Radio Astronomy.

A cascading merger

The astronomers found that the core cluster of galaxies spun out brightly glowing gas that led them to more colliding galaxies. Their computer simulations showed them that this whole structure of 40-plus galaxies will eventually merge into one mega elliptical galaxy.

Sulzenauer explained:

Importantly, this galaxy quartet launches coherent giant tidal arms at 300 kilometers per second [671,081 mph], stretching over an area much larger than the Milky Way. They glow intensely at submillimeter wavelengths, their brightness boosted 10-fold by shockwaves exciting ionized carbon atoms. This bright emission allowed us to precisely measure the motion of gas in this gravitationally ejected spiral, resembling beads on a string encircling the protocluster core.

To our surprise, clumps of tidal debris link to a chain of 20 additional colliding galaxies in the outer parts of the collapsing structure. This hints at a common origin. For the first time, we are witnessing the onset of a cascading merging transformation. Most of the 40 gas-rich galaxies in this core will be destroyed and will eventually transform into a giant elliptical galaxy within less than 300 million years – a mere blink of an eye.

This radio image of the protocluster SPT2349-56 tracks ionized carbon emitted at a wavelength of 158 micrometers. The centers of galaxies are marked with stars, while orange highlights the tidal arms around the inner region. These tidally ejected, galaxy-scale gas clumps are 10 times brighter than astronomers expected. Note the Milky Way for scale at lower right. Image via N. Sulzenauer/ Max Planck Institute for Radio Astronomy.

Case closed on giant galaxies in the early universe?

While the new research provides insight into tidal forces of galaxies and the possibility of creating a huge elliptical out of dozens of smaller galaxies, there’s still much to learn. Co-author Scott Chapman of Dalhousie University said:

While our findings offer exciting new insights into rapid elliptical galaxy assembly, the various interactions between the merger shocks, gas heating from the growth of supermassive black holes, and their effect on the fuel for star formation, remain big mysteries. It might be too early to claim a full understanding of the ‘early childhood’ of giant ellipticals, but we have come a long way in linking tidal debris in protoclusters to the formation process of massive galaxies located in today’s galaxy clusters.

Bottom line: Astronomers used radio data to study the creation of giant galaxies in the early universe. They found some 40 galaxies are tied together and will likely transform into one huge elliptical.

Source: Bright [C II] 158 Micrometer Streamers as a Beacon for Giant Galaxy Formation in SPT2349-56 at z = 4.3

Via Max Planck Institute

Read more: Supermassive black holes in all galaxies? Maybe not

Read more: New Chandra images reveal glorious galaxies and more

The post New clues to how giant galaxies formed in the early universe first appeared on EarthSky.

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Watch a video explaining how giant galaxies in the early universe might have formed. Video via Max Planck Institute for Radio Astronomy.

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

New clues to how giant galaxies formed in the early universe

For decades, astronomers have puzzled over the galaxies they see in the early universe. They’ve spotted massive galaxies just a few billion years after the Big Bang that consist of old stars and are depleted of the gas needed to form new stars. How are galaxies so close to the beginning of the universe already so evolved? On February 10, 2026, astronomers at the Max Planck Institute in Germany said they found evidence a giant elliptical galaxy may form through the rapid collapse of a young galaxy cluster.

The astronomers focused their study on a protocluster – or a massive collection of young galaxies in the early universe – named SPT2349-56. This protocluster existed just 1.4 billion years after the Big Bang, or when the universe was 10% of its current age.

Lead author Nikolaus Sulzenauer, of the Max Planck Institute for Radio Astronomy at the University of Bonn, said:

In a universe where larger galaxies grow hierarchically through gravitational interactions and mergers of smaller building blocks, some giant ellipticals must have formed completely differently than previously thought. Instead of slowly assembling mass throughout 14 billion years, a massive elliptical galaxy might swiftly emerge in just a few hundred million years. It can form through the collapse and coalescence of a major primordial structure, in the time it takes the sun to orbit around the Milky Way’s center once. We find that the structures with the very highest densities must have decoupled first from the universe’s expansion at only 10% of the current cosmic age, and then rapidly assembled entire protoclusters.

The researchers published their peer-reviewed paper in The Astrophysical Journal on February 10, 2026.

Spotlighting a distant protocluster

The researchers used the radio telescopes ALMA and Atacama Pathfinder Experiment in Chile to analyze the cold gas and dust at the center of the protocluster. They chose the protocluster SPT2349-56 – which lies in the direction of the Southern Hemisphere constellation Phoenix – because it’s one of the earliest clusters of massive galaxies that we’ve seen. Co-author Axel Weiss of the Max Planck Institute said:

SPT2349-56 holds the record for the most vigorous stellar factory.

Co-author Ryley Hill from the University of British Columbia in Canada added:

In the center, we found four tightly-interacting galaxies forging one star every 40 minutes.

In comparison, our own Milky Way forms just three to four stars in a year.

Artist’s impression of the protocluster SPT2349-56. These interacting galaxies are different shapes and sizes. Tidal forces are heating the gas (orange) and tearing it apart. We see SPT2349-56 as it looked only 1.4 billion years after the Big Bang, when the universe was 10% of its current age. Image via N.Sulzenauer/ Max Planck Institute for Radio Astronomy.

A cascading merger

The astronomers found that the core cluster of galaxies spun out brightly glowing gas that led them to more colliding galaxies. Their computer simulations showed them that this whole structure of 40-plus galaxies will eventually merge into one mega elliptical galaxy.

Sulzenauer explained:

Importantly, this galaxy quartet launches coherent giant tidal arms at 300 kilometers per second [671,081 mph], stretching over an area much larger than the Milky Way. They glow intensely at submillimeter wavelengths, their brightness boosted 10-fold by shockwaves exciting ionized carbon atoms. This bright emission allowed us to precisely measure the motion of gas in this gravitationally ejected spiral, resembling beads on a string encircling the protocluster core.

To our surprise, clumps of tidal debris link to a chain of 20 additional colliding galaxies in the outer parts of the collapsing structure. This hints at a common origin. For the first time, we are witnessing the onset of a cascading merging transformation. Most of the 40 gas-rich galaxies in this core will be destroyed and will eventually transform into a giant elliptical galaxy within less than 300 million years – a mere blink of an eye.

This radio image of the protocluster SPT2349-56 tracks ionized carbon emitted at a wavelength of 158 micrometers. The centers of galaxies are marked with stars, while orange highlights the tidal arms around the inner region. These tidally ejected, galaxy-scale gas clumps are 10 times brighter than astronomers expected. Note the Milky Way for scale at lower right. Image via N. Sulzenauer/ Max Planck Institute for Radio Astronomy.

Case closed on giant galaxies in the early universe?

While the new research provides insight into tidal forces of galaxies and the possibility of creating a huge elliptical out of dozens of smaller galaxies, there’s still much to learn. Co-author Scott Chapman of Dalhousie University said:

While our findings offer exciting new insights into rapid elliptical galaxy assembly, the various interactions between the merger shocks, gas heating from the growth of supermassive black holes, and their effect on the fuel for star formation, remain big mysteries. It might be too early to claim a full understanding of the ‘early childhood’ of giant ellipticals, but we have come a long way in linking tidal debris in protoclusters to the formation process of massive galaxies located in today’s galaxy clusters.

Bottom line: Astronomers used radio data to study the creation of giant galaxies in the early universe. They found some 40 galaxies are tied together and will likely transform into one huge elliptical.

Source: Bright [C II] 158 Micrometer Streamers as a Beacon for Giant Galaxy Formation in SPT2349-56 at z = 4.3

Via Max Planck Institute

Read more: Supermassive black holes in all galaxies? Maybe not

Read more: New Chandra images reveal glorious galaxies and more

The post New clues to how giant galaxies formed in the early universe first appeared on EarthSky.

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Great Backyard Bird Count begins February 13

Image advertising the 29th Annual Great Backyard Bird Count. Image via birdcount.org

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

Great Backyard Bird Count

The 29th annual Great Backyard Bird Count is set to take place February 13-16, 2026. During this popular community science event, people from all over the world head outdoors to count birds. Scientists use the data to track the health of bird populations.

Watching birds can be a pleasant activity to engage in, and participating in the bird count is free and easy. You just have to commit to counting birds for as little as 15 minutes (or as long as you wish) on one or more days of the four-day event, and report your sightings online at the event’s website. Anyone can take part in the Great Backyard Bird Count, from beginning bird watchers to experts, and you can do the count from your backyard or anywhere in the world. It’s a great way to burn off some of those of extra calories from eating chocolate on Valentine’s Day. Learn more about how to participate here.

A dark-eyed junco seen in Cambridge, Ontario, Canada. Image via Ryan Hodnett/ Wikimedia.

About the Great Backyard Bird Count

The Great Backyard Bird Count is a joint project of the Cornell Lab of Ornithology, National Audubon Society and Birds Canada, and support is provided in part by founding sponsor Wild Birds Unlimited. Chad Wilsey, chief scientist at the National Audubon Society, commented on the value of this event for both birds and people:

By participating in the Great Backyard Bird Count, community scientists contribute data that we use to protect birds and the places they need, today and tomorrow. In return, studies tell us that pausing to observe birds, their sounds and movements and improve human health. Participating in the Great Backyard Bird Count is a win-win for birds and people.

View at EarthSky Community Photos. | Mark Wralstad of Virginia Beach, Virginia, captured this image on January 20, 2025, and wrote: “My Feathersnap bird feeder has captured some great bird shots since I installed it this month but this is one of the brightest visitors I have captured so far! This male Northern Cardinal has become a regular guest.” Thank you, Mark!

How to participate

If you would like to join the 2026 Great Backyard Bird Count, please follow these three easy steps.

1. Familiarize yourself with the event website at the link here.

2. Spend some time counting birds on the weekend of the event at the location of your choice, such as your backyard or a local park. The minimum amount of time required is 15 minutes, but you can count for longer if you wish. During your count, simply record the start and end time, location and number and types of birds that you see. You can perform counts in multiple locations too. Just be sure to submit separate checklists for each location.

And, not to worry if you can’t identify the birds you see at first. Just take good notes about their prominent features such as their size, shape, color and unusual markings, or you can try to snap a closeup picture. Then, you can use a bird guide to look them up later. All About Birds and What Bird are two good online bird identification guides that are free and easy to use.

Additionally, the free Merlin Bird ID app can be downloaded to your smartphone and used offline. Merlin will ask you five simple questions about the bird you are trying to identify and suggest matches for you. Plus, you can even upload a picture to Merlin and let the app try to identify it.

3. The last step involves sending your data to the event’s website. This step usually only takes a few minutes to complete. While you’re visiting the website, check out the live map that displays dots in the various locations where people have submitted a checklist. It’s fun to watch the data pour in from all over the world.

There’s a photo contest too

As an added bonus, there is a photo contest for those who want to submit pictures of the birds that they see during the event. You can even submit photos of yourself bird watching. If you do shoot some good photos, please share them with us at EarthSky Community Photos. We love birding photos!

View at EarthSky Community Photos. | Lynzie Flynn of Fountain Valley, California, submitted this image on December 22, 2024, and wrote: “This is an adult male Vermilion Flycatcher. It was flying from tree to tree and posing for me. It’s such a colorful bird and one of the few colorful birds we see in my area. They are always a treat to see and photograph.” Thank you. Lynzie! Find out more about the Great Backyard Bird Count below.

2025 bird count

During the 2025 count, more than 217 countries and regions reported approximately 8,078 species out of the estimated 10,000 bird species that live on Earth today. Wow!

Use the hashtag #GBBC to follow Great Backyard Bird Count conversations on social media.

The first annual Great Backyard Bird Count was held in 1998, and the event has continued to grow year after year. Hopefully, 2026 will be another record breaker.

View at EarthSky Community Photos. | Stephanie Becker in the San Francisco Bay Area, California, gets a gold star for capturing this photo of a sparrow. She wrote: “In looking forward to the Great Backyard Bird Count, I’ve been observing birds in our backyard. This one is a golden-crowned sparrow enjoying a Golden Delicious apple.” Thanks, Stephanie!

Bottom line: The annual Great Backyard Bird Count runs from February 13-16, 2026. This popular community science project helps scientists keep track of the health of bird populations. Participating is free and easy, so why not give it a try?

Read more: Great Backyard Bird Count

The post Great Backyard Bird Count begins February 13 first appeared on EarthSky.

from EarthSky https://ift.tt/s4hyWtB

Image advertising the 29th Annual Great Backyard Bird Count. Image via birdcount.org

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

Great Backyard Bird Count

The 29th annual Great Backyard Bird Count is set to take place February 13-16, 2026. During this popular community science event, people from all over the world head outdoors to count birds. Scientists use the data to track the health of bird populations.

Watching birds can be a pleasant activity to engage in, and participating in the bird count is free and easy. You just have to commit to counting birds for as little as 15 minutes (or as long as you wish) on one or more days of the four-day event, and report your sightings online at the event’s website. Anyone can take part in the Great Backyard Bird Count, from beginning bird watchers to experts, and you can do the count from your backyard or anywhere in the world. It’s a great way to burn off some of those of extra calories from eating chocolate on Valentine’s Day. Learn more about how to participate here.

A dark-eyed junco seen in Cambridge, Ontario, Canada. Image via Ryan Hodnett/ Wikimedia.

About the Great Backyard Bird Count

The Great Backyard Bird Count is a joint project of the Cornell Lab of Ornithology, National Audubon Society and Birds Canada, and support is provided in part by founding sponsor Wild Birds Unlimited. Chad Wilsey, chief scientist at the National Audubon Society, commented on the value of this event for both birds and people:

By participating in the Great Backyard Bird Count, community scientists contribute data that we use to protect birds and the places they need, today and tomorrow. In return, studies tell us that pausing to observe birds, their sounds and movements and improve human health. Participating in the Great Backyard Bird Count is a win-win for birds and people.

View at EarthSky Community Photos. | Mark Wralstad of Virginia Beach, Virginia, captured this image on January 20, 2025, and wrote: “My Feathersnap bird feeder has captured some great bird shots since I installed it this month but this is one of the brightest visitors I have captured so far! This male Northern Cardinal has become a regular guest.” Thank you, Mark!

How to participate

If you would like to join the 2026 Great Backyard Bird Count, please follow these three easy steps.

1. Familiarize yourself with the event website at the link here.

2. Spend some time counting birds on the weekend of the event at the location of your choice, such as your backyard or a local park. The minimum amount of time required is 15 minutes, but you can count for longer if you wish. During your count, simply record the start and end time, location and number and types of birds that you see. You can perform counts in multiple locations too. Just be sure to submit separate checklists for each location.

And, not to worry if you can’t identify the birds you see at first. Just take good notes about their prominent features such as their size, shape, color and unusual markings, or you can try to snap a closeup picture. Then, you can use a bird guide to look them up later. All About Birds and What Bird are two good online bird identification guides that are free and easy to use.

Additionally, the free Merlin Bird ID app can be downloaded to your smartphone and used offline. Merlin will ask you five simple questions about the bird you are trying to identify and suggest matches for you. Plus, you can even upload a picture to Merlin and let the app try to identify it.

3. The last step involves sending your data to the event’s website. This step usually only takes a few minutes to complete. While you’re visiting the website, check out the live map that displays dots in the various locations where people have submitted a checklist. It’s fun to watch the data pour in from all over the world.

There’s a photo contest too

As an added bonus, there is a photo contest for those who want to submit pictures of the birds that they see during the event. You can even submit photos of yourself bird watching. If you do shoot some good photos, please share them with us at EarthSky Community Photos. We love birding photos!

View at EarthSky Community Photos. | Lynzie Flynn of Fountain Valley, California, submitted this image on December 22, 2024, and wrote: “This is an adult male Vermilion Flycatcher. It was flying from tree to tree and posing for me. It’s such a colorful bird and one of the few colorful birds we see in my area. They are always a treat to see and photograph.” Thank you. Lynzie! Find out more about the Great Backyard Bird Count below.

2025 bird count

During the 2025 count, more than 217 countries and regions reported approximately 8,078 species out of the estimated 10,000 bird species that live on Earth today. Wow!

Use the hashtag #GBBC to follow Great Backyard Bird Count conversations on social media.

The first annual Great Backyard Bird Count was held in 1998, and the event has continued to grow year after year. Hopefully, 2026 will be another record breaker.

View at EarthSky Community Photos. | Stephanie Becker in the San Francisco Bay Area, California, gets a gold star for capturing this photo of a sparrow. She wrote: “In looking forward to the Great Backyard Bird Count, I’ve been observing birds in our backyard. This one is a golden-crowned sparrow enjoying a Golden Delicious apple.” Thanks, Stephanie!

Bottom line: The annual Great Backyard Bird Count runs from February 13-16, 2026. This popular community science project helps scientists keep track of the health of bird populations. Participating is free and easy, so why not give it a try?

Read more: Great Backyard Bird Count

The post Great Backyard Bird Count begins February 13 first appeared on EarthSky.

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2026 has 3 Friday the 13ths. What are the odds?

In 2026, there are 3 Friday the 13ths. They are in February, March and November. Do you believe Friday the 13th is a bad day? An unlucky day? See below to explore the myths and the legacy behind Friday the 13th. Image via Wikimedia Commons (CC BY-SA 3.0).

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

February 13, 2026, is a Friday, ushering in Act I of this year’s epic Friday the 13th trilogy. Plus, we’ll also have a Friday the 13th in March and November. To start things off, we’ll have a Friday the 13th in February, exactly 4 weeks before Friday, March 13, 2026!

Not that we at EarthSky suffer from friggatriskaidekaphobia – an irrational fear of Friday the 13th – but, gosh darn, it’s Friday the 13th three times over in 2026. What’s more, last year’s lone Friday the 13th on June 13, 2025, occurred exactly 39 weeks (3 x 13 weeks) before the Friday the 13th in March 2026. And next year’s lone Friday the 13th on August 13, 2027, will happen exactly 39 weeks (3 x 13 weeks) after the Friday the 13th in November 2026. Follow the links below to learn more about why some people fear this day and about 2015’s three Friday the 13ths.

Gioachino Rossini, a 19th century Italian composer. Folklorists say there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Rossini. Image via Wikimedia Commons. Public domain.

Scary coincidence or super unlucky?

It’s neither a scary coincidence or super unlucky. It’s just a quirk of our calendar, as you’ll see if you keep reading.

The fact is that, according to folklorists, there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Gioachino Rossini. His portrait is above. He doesn’t look scary.

And indeed, Friday has always gotten a bad rap. In the Middle Ages, people would not marry – or set out on a journey – on a Friday.

There are also some links between Christianity and an ill association with either Fridays or the number 13. Jesus was said to be crucified on a Friday. Seating 13 people at a table was seen as bad luck because Judas Iscariot, the disciple who betrayed Jesus, is said to have been the 13th guest at the Last Supper. Meanwhile, our word for Friday comes from Frigga, an ancient Scandinavian fertility and love goddess. Christians called Frigga a witch and Friday the witches’ Sabbath.

In modern times, the slasher-movie franchise Friday the 13th has helped keep friggatriskaidekaphobia alive.

The Friday the 13th slasher-movie franchise helped keep this day maintain its notoriety. Image via Wikimedia Commons

In 2026, blame Thursday

In 2026, you can blame Thursday because the year started on a Thursday. Whenever a common year of 365 days starts on a Thursday, it’s inevitable that the months of February, March and November will start on a Sunday. And any month starting on a Sunday always has a Friday the 13th.

Of course, February has exactly four weeks in a non-leap year. So, for that reason, the days of the week have to match up with the same dates in both February and March during any common year. And in any year, the days of the week always fall on the same dates in both March and November. In short, because the year 2026 started on a Thursday, that means February, March and November all have to start on a Sunday and all must have a Friday the 13th.

The February-March-November Friday the 13th trilogy repeats …

How often does the February-March-November Friday the 13th trilogy repeat? More often than you might imagine! The last February-March-November Friday the 13th year happened 11 years ago, in 2015, for the second time in the 21st century (2001-2100). It will next happen eleven years from now, in 2037. After that, the following February-March-November Friday the 13th year will happen six years after 2037, in the year 2043.

A grand total of eleven February-March-November Friday the 13th years takes place in the 21st century (2001-2100):

2009, 2015, 2026, 2037, 2043, 2054, 2065, 2071, 2082, 2093 and 2099

And because the Gregorian calendar has a 400-year cycle, we also know the February-March-November Friday the 13th years will repeat exactly 400 years later in the 25th century (2401-2500):

2409, 2415, 2426, 2437, 2443, 2454, 2465, 2471, 2482, 2493 and 2499

Calendar for 2026

Calendar for the year 2026. There are 3 Friday the 13ths. They are in February, March and November. Calendar via EarthSky.

The rhyme and reason of the Friday the 13th cycle

Is there any rhyme and reason to the Friday the 13th cycle? Yes, it does make sense. Within the 21st century (2001-2100), note that the February-March-November Friday the 13th years repeat in 28-year cycles (going crosswise):

2009, 2037, 2065, 2093
2015, 2043, 2071, 2099
2026, 2054, 2082

Because the Gregorian calendar suppresses the leap year in 2100, the cycle is perturbed, meaning that all eleven February-March-November Friday the 13th years in the 22nd century (2101-2200) come four years earlier than in the 21st century:

2105, 2111, 2122, 2133, 2139, 2150, 2161, 2167, 2178, 2189 and 2195.

However, within the 22nd century (2101-2200), these Friday the 13th years also repeat in cycles of 28 years.

2105, 2133, 2161, 2189
2111, 2139, 2167, 2195
2122, 2150, 2178

The cycle is perturbed again in the 23rd century (2201-2300):

2201, 2229, 2257, 2285
2207, 2235, 2263, 2291
2218, 2246, 2274

And again in the 24th century (2301-2400):

2303, 2331, 2359, 2387
2314, 2342, 2370, 2398
2325, 2353, 2381

Friday-the-13th-year repetitions within 28-year cycle

Some of you, who might not yet be dazed by calendar numerology, may wonder if some formula governs how a given Friday the 13th year repeats within the 28-year cycle. The answer is a definite yes. Keep in mind that this particular February-March-November Friday the 13th year can only happen in a common year of 365 days, and when January 1 falls on a Thursday.

Therefore, if this threefold Friday the 13th year comes one year after a leap year, the days again match up with the dates in 6, 17 and 28 years afterward. For example, take the year 2009, which comes one year after a leap year:

2009, 2015, 2026, 2037

However, if this triple Friday the 13th year falls two years after a leap year, the days and dates realign in 11, 17 and 28 years. Take the year 2026, which takes place two years after a leap year:

2026, 2037, 2043, 2054

Finally, if this trio of Friday the 13ths happens three years after a leap year, the days recur with the same dates in 11, 22 and 28 years. The year 2015 happens three years after a leap year:

2015, 2026, 2037, 2043

It appears as though cycles of 372 and 400 years prevail over the long course of centuries. Take the year 2015, for instance:

2015 + 372 = 2387

2015 + 400 = 2415

The 372-year period is known as the Gregoriana eclipse cycle, which we elaborate about in our post: How often does a solar eclipse happen on the March equinox?.

Can three Friday the 13ths occur in a leap year?

What about three Friday the 13ths in a leap year? Yes, a leap year can harbor three Friday the 13ths (January 13 – April 13 – July 13) if the leap year starts on a Sunday, which last happened in 2012. However, given that this particular Friday the 13th year happens in a leap year, and a leap year only, it recurs only in periods of 28 years. So the last January-April-July Friday the 13th year happened in 1984, and will next happen in 2040.

If a common year starts on a Thursday, there are three Friday the 13ths; and if a leap year begins on a Sunday, there are three Friday the 13ths. So these are the two scenarios whereby three Friday the 13ths can occur in single calendar year.

Bottom line: From what we have been able to gather, the 400-year cycle displayed by Gregorian calendar features 59 years with three Friday the 13ths, consisting of 44 common years (February – March – November Friday the 13ths) and 15 leap years (January – April – July Friday the 13ths).

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The post 2026 has 3 Friday the 13ths. What are the odds? first appeared on EarthSky.

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In 2026, there are 3 Friday the 13ths. They are in February, March and November. Do you believe Friday the 13th is a bad day? An unlucky day? See below to explore the myths and the legacy behind Friday the 13th. Image via Wikimedia Commons (CC BY-SA 3.0).

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

February 13, 2026, is a Friday, ushering in Act I of this year’s epic Friday the 13th trilogy. Plus, we’ll also have a Friday the 13th in March and November. To start things off, we’ll have a Friday the 13th in February, exactly 4 weeks before Friday, March 13, 2026!

Not that we at EarthSky suffer from friggatriskaidekaphobia – an irrational fear of Friday the 13th – but, gosh darn, it’s Friday the 13th three times over in 2026. What’s more, last year’s lone Friday the 13th on June 13, 2025, occurred exactly 39 weeks (3 x 13 weeks) before the Friday the 13th in March 2026. And next year’s lone Friday the 13th on August 13, 2027, will happen exactly 39 weeks (3 x 13 weeks) after the Friday the 13th in November 2026. Follow the links below to learn more about why some people fear this day and about 2015’s three Friday the 13ths.

Gioachino Rossini, a 19th century Italian composer. Folklorists say there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Rossini. Image via Wikimedia Commons. Public domain.

Scary coincidence or super unlucky?

It’s neither a scary coincidence or super unlucky. It’s just a quirk of our calendar, as you’ll see if you keep reading.

The fact is that, according to folklorists, there’s no written evidence that Friday the 13th was considered unlucky before the 19th century. The earliest known documented reference in English appears to be in Henry Sutherland Edwards’ 1869 biography of Gioachino Rossini. His portrait is above. He doesn’t look scary.

And indeed, Friday has always gotten a bad rap. In the Middle Ages, people would not marry – or set out on a journey – on a Friday.

There are also some links between Christianity and an ill association with either Fridays or the number 13. Jesus was said to be crucified on a Friday. Seating 13 people at a table was seen as bad luck because Judas Iscariot, the disciple who betrayed Jesus, is said to have been the 13th guest at the Last Supper. Meanwhile, our word for Friday comes from Frigga, an ancient Scandinavian fertility and love goddess. Christians called Frigga a witch and Friday the witches’ Sabbath.

In modern times, the slasher-movie franchise Friday the 13th has helped keep friggatriskaidekaphobia alive.

The Friday the 13th slasher-movie franchise helped keep this day maintain its notoriety. Image via Wikimedia Commons

In 2026, blame Thursday

In 2026, you can blame Thursday because the year started on a Thursday. Whenever a common year of 365 days starts on a Thursday, it’s inevitable that the months of February, March and November will start on a Sunday. And any month starting on a Sunday always has a Friday the 13th.

Of course, February has exactly four weeks in a non-leap year. So, for that reason, the days of the week have to match up with the same dates in both February and March during any common year. And in any year, the days of the week always fall on the same dates in both March and November. In short, because the year 2026 started on a Thursday, that means February, March and November all have to start on a Sunday and all must have a Friday the 13th.

The February-March-November Friday the 13th trilogy repeats …

How often does the February-March-November Friday the 13th trilogy repeat? More often than you might imagine! The last February-March-November Friday the 13th year happened 11 years ago, in 2015, for the second time in the 21st century (2001-2100). It will next happen eleven years from now, in 2037. After that, the following February-March-November Friday the 13th year will happen six years after 2037, in the year 2043.

A grand total of eleven February-March-November Friday the 13th years takes place in the 21st century (2001-2100):

2009, 2015, 2026, 2037, 2043, 2054, 2065, 2071, 2082, 2093 and 2099

And because the Gregorian calendar has a 400-year cycle, we also know the February-March-November Friday the 13th years will repeat exactly 400 years later in the 25th century (2401-2500):

2409, 2415, 2426, 2437, 2443, 2454, 2465, 2471, 2482, 2493 and 2499

Calendar for 2026

Calendar for the year 2026. There are 3 Friday the 13ths. They are in February, March and November. Calendar via EarthSky.

The rhyme and reason of the Friday the 13th cycle

Is there any rhyme and reason to the Friday the 13th cycle? Yes, it does make sense. Within the 21st century (2001-2100), note that the February-March-November Friday the 13th years repeat in 28-year cycles (going crosswise):

2009, 2037, 2065, 2093
2015, 2043, 2071, 2099
2026, 2054, 2082

Because the Gregorian calendar suppresses the leap year in 2100, the cycle is perturbed, meaning that all eleven February-March-November Friday the 13th years in the 22nd century (2101-2200) come four years earlier than in the 21st century:

2105, 2111, 2122, 2133, 2139, 2150, 2161, 2167, 2178, 2189 and 2195.

However, within the 22nd century (2101-2200), these Friday the 13th years also repeat in cycles of 28 years.

2105, 2133, 2161, 2189
2111, 2139, 2167, 2195
2122, 2150, 2178

The cycle is perturbed again in the 23rd century (2201-2300):

2201, 2229, 2257, 2285
2207, 2235, 2263, 2291
2218, 2246, 2274

And again in the 24th century (2301-2400):

2303, 2331, 2359, 2387
2314, 2342, 2370, 2398
2325, 2353, 2381

Friday-the-13th-year repetitions within 28-year cycle

Some of you, who might not yet be dazed by calendar numerology, may wonder if some formula governs how a given Friday the 13th year repeats within the 28-year cycle. The answer is a definite yes. Keep in mind that this particular February-March-November Friday the 13th year can only happen in a common year of 365 days, and when January 1 falls on a Thursday.

Therefore, if this threefold Friday the 13th year comes one year after a leap year, the days again match up with the dates in 6, 17 and 28 years afterward. For example, take the year 2009, which comes one year after a leap year:

2009, 2015, 2026, 2037

However, if this triple Friday the 13th year falls two years after a leap year, the days and dates realign in 11, 17 and 28 years. Take the year 2026, which takes place two years after a leap year:

2026, 2037, 2043, 2054

Finally, if this trio of Friday the 13ths happens three years after a leap year, the days recur with the same dates in 11, 22 and 28 years. The year 2015 happens three years after a leap year:

2015, 2026, 2037, 2043

It appears as though cycles of 372 and 400 years prevail over the long course of centuries. Take the year 2015, for instance:

2015 + 372 = 2387

2015 + 400 = 2415

The 372-year period is known as the Gregoriana eclipse cycle, which we elaborate about in our post: How often does a solar eclipse happen on the March equinox?.

Can three Friday the 13ths occur in a leap year?

What about three Friday the 13ths in a leap year? Yes, a leap year can harbor three Friday the 13ths (January 13 – April 13 – July 13) if the leap year starts on a Sunday, which last happened in 2012. However, given that this particular Friday the 13th year happens in a leap year, and a leap year only, it recurs only in periods of 28 years. So the last January-April-July Friday the 13th year happened in 1984, and will next happen in 2040.

If a common year starts on a Thursday, there are three Friday the 13ths; and if a leap year begins on a Sunday, there are three Friday the 13ths. So these are the two scenarios whereby three Friday the 13ths can occur in single calendar year.

Bottom line: From what we have been able to gather, the 400-year cycle displayed by Gregorian calendar features 59 years with three Friday the 13ths, consisting of 44 common years (February – March – November Friday the 13ths) and 15 leap years (January – April – July Friday the 13ths).

Enjoying EarthSky so far? Sign up for our free daily newsletter today!

The post 2026 has 3 Friday the 13ths. What are the odds? first appeared on EarthSky.

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Tatooine exoplanets are oddly rare, and we finally know why

Artist’s concept of a planet – the black dot – orbiting a pair of stars in a binary star system. A new study says Einstein’s general theory of relativity can explain why these Tatooine exoplanets seem to be rarer than 1st thought. Image via NASA/ Goddard Space Flight Center.

• Tatooine planets are exoplanets that orbit two stars instead of just one. The name comes from the fictional arid desert world in “Star Wars.”
• These planets seem to be rarer than first thought, although they do exist.
• Einstein’s general theory of relativity – specifically the gravitational effects of the two stars – is to blame for their rarity, according to a new study.

EarthSky’s 2026 lunar calendar shows every day’s moon phase. Get yours today!

Tatooine exoplanets are rare

In “Star Wars,” the planet Tatooine was remarkable because it orbited a pair of stars, not just one. And astronomers have found real examples of Tatooine worlds, called circumbinary planets. But they seem to be rare. Why? On January 30, 2026, scientists said Einstein’s general theory of relativity is to blame. Over time, the orbits of the two stars around each other shrink. As a consequence, the planet’s orbit becomes wildly elongated. Ultimately, the planet will either be consumed by one of the stars or get ejected from the system entirely.

The theory of general relativity basically says the observed gravitational effect between masses – such as a pair of binary stars – results from their warping of spacetime. It interprets gravity as a warping of the fabric of spacetime by a mass, similar to how a person on a trampoline warps the surface and makes other objects on the trampoline fall inward toward the person.

Astrophysicists at the University of California, Berkeley and the American University of Beirut in Lebanon published their peer-reviewed findings in The Astrophysical Journal Letters on December 8, 2025.

University of California, Berkeley: Why Are Tatooine Planets Rare? Blame General Relativity. news.berkeley.edu/2026/01/30/w…

— AAS Press Office (@press.aas.org) 2026-02-02T16:14:05.036Z

A dearth of binary star exoplanets

Astronomers had found massive exoplanets – like Jupiter and Saturn in our solar system – around 10% of single, sunlike stars. These were in the datasets from the Kepler and TESS space telescopes, about 300 planets overall. They had expected to find similar numbers orbiting binary stars also. However, they only found 47 candidate planets and 14 confirmed planets. Lead author Mohammad Farhat, a Miller Postdoctoral Fellow at UC Berkeley, said:

You have a scarcity of circumbinary planets in general and you have an absolute desert around binaries with orbital periods of seven days or less. The overwhelming majority of eclipsing binaries are tight binaries and are precisely the systems around which we most expect to find transiting circumbinary planets.

View larger. | This diagram shows the step-by-step explanation for why planets that orbit binary stars eventually enter an unstable orbit and disappear from the system. Image via Mohammad Farhat/ UC Berkeley.

The instability zone

Binary star systems have an instability zone. This is a region where no planet can survive for long, and it ties in with the theory of relativity. The gravitational interactions of a planet and both stars can be chaotic. As a result, the planet will either be consumed or shredded by one of the stars, or it will be expelled from the system altogether. Indeed, 12 of the 14 confirmed planets orbiting close binary stars orbit just beyond the edge of this instability zone. This is why they are still safe. As Farhat explained:

Planets form from the bottom up, by sticking small-scale planetesimals together. But forming a planet at the edge of the instability zone would be like trying to stick snowflakes together in a hurricane.

General theory of relativity is to blame

The researchers found general relativity had a significant effect on planets orbiting binary stars. They calculated that eight out of 10 such planets would be disrupted in their orbits. And 75% of those would end up being destroyed. Why does this happen?

In binary star systems, the stars usually have similar, but not identical, masses. They orbit each other in elongated, egg-shaped orbits. If there is a planet orbiting both stars, the gravity from the stars will cause the planet’s orbit to precess, similar to how the axis of a spinning top wobbles. Precession is the slow gyration of the rotation axis of a spinning body around another line intersecting it.

The orbit of the planet Mercury also experiences precession. In fact, it’s slightly higher than predicted by the earlier theory of gravity by Isaac Newton. The additional precession is explained by the general theory of relativity.

Mohammad Farhat, a Miller Postdoctoral Fellow at University of California, Berkeley, is the lead author of the new study about Tatooine planets orbiting binary stars and Einstein’s general theory of relativity. Image via University of California, Berkeley.

2 possible fates of Tatooine exoplanets

The orbits of the two binary stars also undergo precession, due mostly to general relativity. The distance between the two stars gradually shrinks over time. As the precession rate of the stars increases, the precession rate of the planet slows down. Eventually, the two precession rates will match and become in resonance. As a result, the planet’s orbit becomes even more elongated. As Farhat explained, there are then two possible outcomes for the planet, neither of which are good:

Two things can happen: Either the planet gets very, very close to the binary, suffering tidal disruption or being engulfed by one of the stars, or its orbit gets significantly perturbed by the binary to be eventually ejected from the system. In both cases, you get rid of the planet.

Co-author Jihad Touma, a physics professor at the American University of Beirut, added:

A planet caught in resonance finds its orbit deformed to higher and higher eccentricities, precessing faster and faster while staying in tune with the orbit of the binary, which is shrinking. And on the route, it encounters that instability zone around binaries, where three-body effects kick into place and gravitationally clear out the zone.

View larger. | Artist’s concept of an alien sunset from a planet with 2 suns. Image via NASA/ JPL-Caltech/ University of Arizona.

Opposite effects of general relativity

Curiously, general relativity could stabilize some planetary systems, like Mercury, yet destabilize others, as Touma noted:

Interestingly enough, nearly a century following Einstein’s calculations, computer simulations showed how relativistic effects may have saved Mercury from chaotic diffusion out of the solar system. Here we see related effects at work disrupting planetary systems. General relativity is stabilizing systems in some ways and disturbing them in other ways.

Bottom line: Tatooine exoplanets – planets orbiting two stars – are less common than scientists first thought. A new study says Einstein’s general theory of relativity is to blame for their rarity.

Source: Capture into Apsidal Resonance and the Decimation of Planets around Inspiraling Binaries

Via University of California, Berkeley

Read more: Rare Tatooine world has a weird orbit around brown dwarfs

Read more: Tatooine exoplanets may be more habitable than we thought

The post Tatooine exoplanets are oddly rare, and we finally know why first appeared on EarthSky.

from EarthSky https://ift.tt/HSJ0RzY

Artist’s concept of a planet – the black dot – orbiting a pair of stars in a binary star system. A new study says Einstein’s general theory of relativity can explain why these Tatooine exoplanets seem to be rarer than 1st thought. Image via NASA/ Goddard Space Flight Center.

• Tatooine planets are exoplanets that orbit two stars instead of just one. The name comes from the fictional arid desert world in “Star Wars.”
• These planets seem to be rarer than first thought, although they do exist.
• Einstein’s general theory of relativity – specifically the gravitational effects of the two stars – is to blame for their rarity, according to a new study.

EarthSky’s 2026 lunar calendar shows every day’s moon phase. Get yours today!

Tatooine exoplanets are rare

In “Star Wars,” the planet Tatooine was remarkable because it orbited a pair of stars, not just one. And astronomers have found real examples of Tatooine worlds, called circumbinary planets. But they seem to be rare. Why? On January 30, 2026, scientists said Einstein’s general theory of relativity is to blame. Over time, the orbits of the two stars around each other shrink. As a consequence, the planet’s orbit becomes wildly elongated. Ultimately, the planet will either be consumed by one of the stars or get ejected from the system entirely.

The theory of general relativity basically says the observed gravitational effect between masses – such as a pair of binary stars – results from their warping of spacetime. It interprets gravity as a warping of the fabric of spacetime by a mass, similar to how a person on a trampoline warps the surface and makes other objects on the trampoline fall inward toward the person.

Astrophysicists at the University of California, Berkeley and the American University of Beirut in Lebanon published their peer-reviewed findings in The Astrophysical Journal Letters on December 8, 2025.

University of California, Berkeley: Why Are Tatooine Planets Rare? Blame General Relativity. news.berkeley.edu/2026/01/30/w…

— AAS Press Office (@press.aas.org) 2026-02-02T16:14:05.036Z

A dearth of binary star exoplanets

Astronomers had found massive exoplanets – like Jupiter and Saturn in our solar system – around 10% of single, sunlike stars. These were in the datasets from the Kepler and TESS space telescopes, about 300 planets overall. They had expected to find similar numbers orbiting binary stars also. However, they only found 47 candidate planets and 14 confirmed planets. Lead author Mohammad Farhat, a Miller Postdoctoral Fellow at UC Berkeley, said:

You have a scarcity of circumbinary planets in general and you have an absolute desert around binaries with orbital periods of seven days or less. The overwhelming majority of eclipsing binaries are tight binaries and are precisely the systems around which we most expect to find transiting circumbinary planets.

View larger. | This diagram shows the step-by-step explanation for why planets that orbit binary stars eventually enter an unstable orbit and disappear from the system. Image via Mohammad Farhat/ UC Berkeley.

The instability zone

Binary star systems have an instability zone. This is a region where no planet can survive for long, and it ties in with the theory of relativity. The gravitational interactions of a planet and both stars can be chaotic. As a result, the planet will either be consumed or shredded by one of the stars, or it will be expelled from the system altogether. Indeed, 12 of the 14 confirmed planets orbiting close binary stars orbit just beyond the edge of this instability zone. This is why they are still safe. As Farhat explained:

Planets form from the bottom up, by sticking small-scale planetesimals together. But forming a planet at the edge of the instability zone would be like trying to stick snowflakes together in a hurricane.

General theory of relativity is to blame

The researchers found general relativity had a significant effect on planets orbiting binary stars. They calculated that eight out of 10 such planets would be disrupted in their orbits. And 75% of those would end up being destroyed. Why does this happen?

In binary star systems, the stars usually have similar, but not identical, masses. They orbit each other in elongated, egg-shaped orbits. If there is a planet orbiting both stars, the gravity from the stars will cause the planet’s orbit to precess, similar to how the axis of a spinning top wobbles. Precession is the slow gyration of the rotation axis of a spinning body around another line intersecting it.

The orbit of the planet Mercury also experiences precession. In fact, it’s slightly higher than predicted by the earlier theory of gravity by Isaac Newton. The additional precession is explained by the general theory of relativity.

Mohammad Farhat, a Miller Postdoctoral Fellow at University of California, Berkeley, is the lead author of the new study about Tatooine planets orbiting binary stars and Einstein’s general theory of relativity. Image via University of California, Berkeley.

2 possible fates of Tatooine exoplanets

The orbits of the two binary stars also undergo precession, due mostly to general relativity. The distance between the two stars gradually shrinks over time. As the precession rate of the stars increases, the precession rate of the planet slows down. Eventually, the two precession rates will match and become in resonance. As a result, the planet’s orbit becomes even more elongated. As Farhat explained, there are then two possible outcomes for the planet, neither of which are good:

Two things can happen: Either the planet gets very, very close to the binary, suffering tidal disruption or being engulfed by one of the stars, or its orbit gets significantly perturbed by the binary to be eventually ejected from the system. In both cases, you get rid of the planet.

Co-author Jihad Touma, a physics professor at the American University of Beirut, added:

A planet caught in resonance finds its orbit deformed to higher and higher eccentricities, precessing faster and faster while staying in tune with the orbit of the binary, which is shrinking. And on the route, it encounters that instability zone around binaries, where three-body effects kick into place and gravitationally clear out the zone.

View larger. | Artist’s concept of an alien sunset from a planet with 2 suns. Image via NASA/ JPL-Caltech/ University of Arizona.

Opposite effects of general relativity

Curiously, general relativity could stabilize some planetary systems, like Mercury, yet destabilize others, as Touma noted:

Interestingly enough, nearly a century following Einstein’s calculations, computer simulations showed how relativistic effects may have saved Mercury from chaotic diffusion out of the solar system. Here we see related effects at work disrupting planetary systems. General relativity is stabilizing systems in some ways and disturbing them in other ways.

Bottom line: Tatooine exoplanets – planets orbiting two stars – are less common than scientists first thought. A new study says Einstein’s general theory of relativity is to blame for their rarity.

Source: Capture into Apsidal Resonance and the Decimation of Planets around Inspiraling Binaries

Via University of California, Berkeley

Read more: Rare Tatooine world has a weird orbit around brown dwarfs

Read more: Tatooine exoplanets may be more habitable than we thought

The post Tatooine exoplanets are oddly rare, and we finally know why first appeared on EarthSky.

from EarthSky https://ift.tt/HSJ0RzY

The stars Shaula and Lesath herald the coming spring

If you’re in the Northern Hemisphere, Shaula and Lesath will come over your southeastern horizon before dawn sometime this month. They’re a hopeful sign that spring is coming.

How do you recognize the coming of spring? Maybe you spot a first returning robin. Or tune into news about a groundhog looking for its shadow. For stargazers, one sign of spring is the early-morning sighting of a pretty pair of stars in the constellation Scorpius the Scorpion. Those stars, known as Shaula and Lesath, are part of the Stinger of the Scorpion. They are located at the end of the Scorpion’s curved Tail.

Shaula and Lesath in Pawnee lore

The Pawnee – once the largest group of people living on the U.S. Central Plains – viewed the sky as a calendar. Different stars foretold the change of seasons. Many of their seasonal rituals occurred according to their observations of stars and planets. The most important of these was the Spring Awakening ceremony, tied to the observation of Shaula and Lesath on cold February mornings. The American anthropologist Gene Weltfish wrote in her 1977 book The Lost Universe: Pawnee Life and Culture:

The position of the stars was an important guide to the time when this ceremony should be held. The earth-lodge served as an astronomical observatory and as the priests sat inside at the west, they could observe the stars in certain positions through the smokehole and through the long east-oriented entranceway. They also kept careful watch of the horizon right after sunset and just before dawn to note the order and position of the stars.

The ceremony must be held at exactly the right time of year, when the priest first tracked two small twinkling stars known as the Swimming Ducks in the … horizon near the Milky Way.

When the Swimming Ducks came into view in the southeast – before daybreak in the month of February – the Pawnee recognized that it was time to begin planting ceremonies. The return of the celestial ducks to open water on the river of the Milky Way signaled the first stirrings of the great plains from hibernation.

Shaula and Lesath’s presence over the horizon was symbolic of waterfowl breaking through the ice. These stars were a sign of hope that spring was on its way.

In a dark sky, you can see that the starlit band of the Milky Way runs behind Shaula and Lesath in the Tail of Scorpius. Photo via Daniel McVey.

How to see the Swimming Ducks

You can see this harbinger of spring for yourself as Shaula and Lesath come into view at or shortly before dawn. You’ll need a clear, unobstructed view to the south to southeast to spot these stars, flickering by the horizon. If you view the constellation of Scorpius as a tilted J, the pair of stars is found at the end of the J shape. Daybreak may make them difficult to find, but keep looking throughout February. Eventually you’ll spot them low along the horizon.

As we approach the end of winter, Shaula and Lesath will appear higher each morning in the southeast before dawn. Their morning appearance tells us that spring is not far away.

Bottom line: The early Pawnee of the U.S. Central Plains regarded the stars Shaula and Lesath – in the Stinger of Scorpius the Scorpion – as Swimming Ducks. When the Swimming Ducks appeared before dawn in winter, the Pawnee knew spring was near and would begin planting ceremonies. So in some respects, these stars were a Pawnee version of Groundhog Day.

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If you’re in the Northern Hemisphere, Shaula and Lesath will come over your southeastern horizon before dawn sometime this month. They’re a hopeful sign that spring is coming.

How do you recognize the coming of spring? Maybe you spot a first returning robin. Or tune into news about a groundhog looking for its shadow. For stargazers, one sign of spring is the early-morning sighting of a pretty pair of stars in the constellation Scorpius the Scorpion. Those stars, known as Shaula and Lesath, are part of the Stinger of the Scorpion. They are located at the end of the Scorpion’s curved Tail.

Shaula and Lesath in Pawnee lore

The Pawnee – once the largest group of people living on the U.S. Central Plains – viewed the sky as a calendar. Different stars foretold the change of seasons. Many of their seasonal rituals occurred according to their observations of stars and planets. The most important of these was the Spring Awakening ceremony, tied to the observation of Shaula and Lesath on cold February mornings. The American anthropologist Gene Weltfish wrote in her 1977 book The Lost Universe: Pawnee Life and Culture:

The position of the stars was an important guide to the time when this ceremony should be held. The earth-lodge served as an astronomical observatory and as the priests sat inside at the west, they could observe the stars in certain positions through the smokehole and through the long east-oriented entranceway. They also kept careful watch of the horizon right after sunset and just before dawn to note the order and position of the stars.

The ceremony must be held at exactly the right time of year, when the priest first tracked two small twinkling stars known as the Swimming Ducks in the … horizon near the Milky Way.

When the Swimming Ducks came into view in the southeast – before daybreak in the month of February – the Pawnee recognized that it was time to begin planting ceremonies. The return of the celestial ducks to open water on the river of the Milky Way signaled the first stirrings of the great plains from hibernation.

Shaula and Lesath’s presence over the horizon was symbolic of waterfowl breaking through the ice. These stars were a sign of hope that spring was on its way.

In a dark sky, you can see that the starlit band of the Milky Way runs behind Shaula and Lesath in the Tail of Scorpius. Photo via Daniel McVey.

How to see the Swimming Ducks

You can see this harbinger of spring for yourself as Shaula and Lesath come into view at or shortly before dawn. You’ll need a clear, unobstructed view to the south to southeast to spot these stars, flickering by the horizon. If you view the constellation of Scorpius as a tilted J, the pair of stars is found at the end of the J shape. Daybreak may make them difficult to find, but keep looking throughout February. Eventually you’ll spot them low along the horizon.

As we approach the end of winter, Shaula and Lesath will appear higher each morning in the southeast before dawn. Their morning appearance tells us that spring is not far away.

Bottom line: The early Pawnee of the U.S. Central Plains regarded the stars Shaula and Lesath – in the Stinger of Scorpius the Scorpion – as Swimming Ducks. When the Swimming Ducks appeared before dawn in winter, the Pawnee knew spring was near and would begin planting ceremonies. So in some respects, these stars were a Pawnee version of Groundhog Day.

The post The stars Shaula and Lesath herald the coming spring first appeared on EarthSky.

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Galaxy MoM-z14 confirmed as most distant object ever seen

Spotted by NASA’s James Webb Space Telescope, the galaxy MoM-z14 is currently the farthest galaxy ever detected. We see MoM-z14 as it appeared in the distant past, only 280 million years after the universe began in the Big Bang. Its light has traveled through space for more than 13 billion years. Image via NASA/ ESA/ CSA/ STScI/ Rohan Naidu (MIT)/ Joseph DePasquale (STScI).

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

Ancient Galaxy MoM-z14 confirmed as most distant object ever seen

Astronomers have confirmed that the galaxy MoM-z14 is the most distant object yet measured. This galaxy’s light has been traveling to us for 13.53 billion years, meaning we see MoM-z14 as it appeared just 280 million years after the Big Bang. And, thanks to the universe’s expansion, the galaxy is currently 33.8 billion light-years away.

An anomaly from the universe’s infancy, MoM-z14 isn’t at all what astronomers expected to find when they peered into the deepest depths of space.

It’s one of a group of extremely ancient but oddly well-developed galaxies imaged by the James Webb Space Telescope. They appear to be up to 13.5 billion years old, and are far more complex than cosmological theory says they should be. That’s why there have been doubts over whether the galaxies are truly that old. Have gravitational distortions been giving us a false picture?

To answer the question, astronomers designed and ran the “Mirage or Miracle” (MoM) survey. A group of dozens of international researchers used Webb’s spectroscopic instruments – tools that measure the chemical signatures hidden in light – to confirm that the light coming from MoM-z14 has, indeed, travelled for 13.53 billion years. That means MoM-z14 is about 97.8% as old as the universe.

The peer-reviewed findings from the survey were reported in the Open Journal of Astrophysics on January 28.

Is Galaxy MoM-z14 normal or unique?

The earliest galaxies imaged by Webb are more developed than theories predicted. Plus, there are too many of them. The newly published research sought, firstly, to discover if objects like MoM-z14 are actually as distant as they appear. Secondly, researchers wanted to find out if their unexpected structures are peculiar or commonplace. Lead author Rohan Naidu of MIT’s Kavli Institute for Astrophysics and Space Research said:

With Webb, we are able to see farther than humans ever have before, and it looks nothing like what we predicted, which is both challenging and exciting.

Before Webb began observation, cosmological theory predicted there would be only a few developed galaxies so soon after the Big Bang. Instead, initial imagery revealed about 100 times more such objects than expected, including the galaxy MoM-z14. Data from Webb’s spectrographic camera allowed researchers to confirm whether these objects were as old as they appear, said Pascal Oesch of the University of Geneva, co-principal investigator of the survey:

We can estimate the distance of galaxies from images, but it’s really important to follow up and confirm with more detailed spectroscopy so that we know exactly what we are seeing, and when.

The objects really are from an era 280 million years after the beginning of everything. And that’s a discovery that prompts more exploration, said Jacob Shen, a postdoctoral researcher at MIT and a member of the research team:

There is a growing chasm between theory and observation related to the early universe, which presents compelling questions to be explored going forward.

Expect more discoveries from the more distant past

The data Webb has already returned are showing that the nature of early stars isn’t what we thought either. Stars in MoMz-14 appear to have more nitrogen than expected. Naidu said:

We can take a page from archeology and look at these ancient stars in our own galaxy like fossils from the early universe, except in astronomy we are lucky enough to have Webb seeing so far that we also have direct information about galaxies during that time. It turns out we are seeing some of the same features, like this unusual nitrogen enrichment.

Since there shouldn’t have been enough time to produce the amount of nitrogen seen in early stars, researchers are already reworking their theories on how it got there. They speculate there might have been enough dense gas to form nitrogen-generating supergiant stars very early.

More to come

More data are needed to unravel these mysteries of the early universe. And new astronomical instruments like the Nancy Grace Roman Space Telescope will help provide that information. Yijia Li, a graduate student at the Pennsylvania State University and a member of the research team, said:

To figure out what is going on in the early universe, we really need more information — more detailed observations with Webb, and more galaxies to see where the common features are, which Roman will be able to provide. It’s an incredibly exciting time, with Webb revealing the early universe like never before and showing us how much there still is to discover.

That means Galaxy MoM-z14’s hold on the title of most distant object ever observed likely won’t last long. Roman is set to launch in May 2026. As it and Webb continue to explore the earliest era of the universe, more distant – and, therefore, older – objects will almost certainly be discovered.

Bottom line: Galaxy MoM-z14 – a bright galaxy that existed 280 million years after the Big Bang – is for now the most distant object ever measured by astronomers. It is currently 33.8 billion light years away.

Source A Cosmic Miracle: A Remarkably Luminous Galaxy at z spec = 14.44 Confirmed with JWST

Via NASA

Read more: 3 years of the Webb telescope: Here’s what it’s discovered

The post Galaxy MoM-z14 confirmed as most distant object ever seen first appeared on EarthSky.

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Spotted by NASA’s James Webb Space Telescope, the galaxy MoM-z14 is currently the farthest galaxy ever detected. We see MoM-z14 as it appeared in the distant past, only 280 million years after the universe began in the Big Bang. Its light has traveled through space for more than 13 billion years. Image via NASA/ ESA/ CSA/ STScI/ Rohan Naidu (MIT)/ Joseph DePasquale (STScI).

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

Ancient Galaxy MoM-z14 confirmed as most distant object ever seen

Astronomers have confirmed that the galaxy MoM-z14 is the most distant object yet measured. This galaxy’s light has been traveling to us for 13.53 billion years, meaning we see MoM-z14 as it appeared just 280 million years after the Big Bang. And, thanks to the universe’s expansion, the galaxy is currently 33.8 billion light-years away.

An anomaly from the universe’s infancy, MoM-z14 isn’t at all what astronomers expected to find when they peered into the deepest depths of space.

It’s one of a group of extremely ancient but oddly well-developed galaxies imaged by the James Webb Space Telescope. They appear to be up to 13.5 billion years old, and are far more complex than cosmological theory says they should be. That’s why there have been doubts over whether the galaxies are truly that old. Have gravitational distortions been giving us a false picture?

To answer the question, astronomers designed and ran the “Mirage or Miracle” (MoM) survey. A group of dozens of international researchers used Webb’s spectroscopic instruments – tools that measure the chemical signatures hidden in light – to confirm that the light coming from MoM-z14 has, indeed, travelled for 13.53 billion years. That means MoM-z14 is about 97.8% as old as the universe.

The peer-reviewed findings from the survey were reported in the Open Journal of Astrophysics on January 28.

Is Galaxy MoM-z14 normal or unique?

The earliest galaxies imaged by Webb are more developed than theories predicted. Plus, there are too many of them. The newly published research sought, firstly, to discover if objects like MoM-z14 are actually as distant as they appear. Secondly, researchers wanted to find out if their unexpected structures are peculiar or commonplace. Lead author Rohan Naidu of MIT’s Kavli Institute for Astrophysics and Space Research said:

With Webb, we are able to see farther than humans ever have before, and it looks nothing like what we predicted, which is both challenging and exciting.

Before Webb began observation, cosmological theory predicted there would be only a few developed galaxies so soon after the Big Bang. Instead, initial imagery revealed about 100 times more such objects than expected, including the galaxy MoM-z14. Data from Webb’s spectrographic camera allowed researchers to confirm whether these objects were as old as they appear, said Pascal Oesch of the University of Geneva, co-principal investigator of the survey:

We can estimate the distance of galaxies from images, but it’s really important to follow up and confirm with more detailed spectroscopy so that we know exactly what we are seeing, and when.

The objects really are from an era 280 million years after the beginning of everything. And that’s a discovery that prompts more exploration, said Jacob Shen, a postdoctoral researcher at MIT and a member of the research team:

There is a growing chasm between theory and observation related to the early universe, which presents compelling questions to be explored going forward.

Expect more discoveries from the more distant past

The data Webb has already returned are showing that the nature of early stars isn’t what we thought either. Stars in MoMz-14 appear to have more nitrogen than expected. Naidu said:

We can take a page from archeology and look at these ancient stars in our own galaxy like fossils from the early universe, except in astronomy we are lucky enough to have Webb seeing so far that we also have direct information about galaxies during that time. It turns out we are seeing some of the same features, like this unusual nitrogen enrichment.

Since there shouldn’t have been enough time to produce the amount of nitrogen seen in early stars, researchers are already reworking their theories on how it got there. They speculate there might have been enough dense gas to form nitrogen-generating supergiant stars very early.

More to come

More data are needed to unravel these mysteries of the early universe. And new astronomical instruments like the Nancy Grace Roman Space Telescope will help provide that information. Yijia Li, a graduate student at the Pennsylvania State University and a member of the research team, said:

To figure out what is going on in the early universe, we really need more information — more detailed observations with Webb, and more galaxies to see where the common features are, which Roman will be able to provide. It’s an incredibly exciting time, with Webb revealing the early universe like never before and showing us how much there still is to discover.

That means Galaxy MoM-z14’s hold on the title of most distant object ever observed likely won’t last long. Roman is set to launch in May 2026. As it and Webb continue to explore the earliest era of the universe, more distant – and, therefore, older – objects will almost certainly be discovered.

Bottom line: Galaxy MoM-z14 – a bright galaxy that existed 280 million years after the Big Bang – is for now the most distant object ever measured by astronomers. It is currently 33.8 billion light years away.

Source A Cosmic Miracle: A Remarkably Luminous Galaxy at z spec = 14.44 Confirmed with JWST

Via NASA

Read more: 3 years of the Webb telescope: Here’s what it’s discovered

The post Galaxy MoM-z14 confirmed as most distant object ever seen first appeared on EarthSky.

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