Orion the Hunter is easy to spot in January

EarthSky founder Deborah Byrd wants you to come to know the constellation Orion the Hunter. It’s one of the most famous constellations because it’s easy to identify, with several noticeably bright and interesting stars. Plus, Orion can help you visualize your place in the Milky Way galaxy. What’s not to like? Click here for the video. Prefer to read? See below!

Tonight look for the constellation Orion the Hunter. It’s a constant companion on winter evenings in the Northern Hemisphere, and on summer nights in the Southern Hemisphere. Plus, it’s probably the easiest constellation to spot thanks to its distinctive Belt. Orion’s Belt consists of three medium-bright stars in a short, straight row at the Hunter’s waistline. So if you see any three equally bright stars in a row this evening, you’re probably looking at Orion. Do you want to be sure? There are two even brighter stars – one reddish and the other blue – on either side of the Belt stars.

2025 lunar calendars on sale now. Makes a great gift! Check it out here.

If you want to learn just one constellation … this is a good one! And it’s very easy constellation to spot. Those of us in the Northern Hemisphere see Orion the Hunter arcing across the southern sky on January evenings. Southern Hemisphere? Turn this chart upside-down, and look in your northern sky. To see a precise view from your location, try Stellarium Online.

When to look for Orion

As seen from mid-northern latitudes, you’ll find Orion in the southeast in the January early evening and shining high in the south by mid-to-late evening (around 9 to 10 p.m. local time, the time on your clock wherever you live). If you live at temperate latitudes south of the equator, you’ll see Orion high in your northern sky around that same hour.

View at EarthSky Community Photos. | Amr Abdulwahab created this composite image of the constellation Orion the Hunter on January 1, 2023, in H-alpha. That wavelength explains why you can see the great red loop around Orion known as Barnard’s Loop. Amr wrote: “Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the oldest and most recognizable constellations, with its 3 main stars forming a distinctive ‘belt’ shape. These stars are named Alnitak, Alnilam and Mintaka. The constellation also features several bright stars, including Betelgeuse and Rigel, as well as the Orion Nebula, a bright cloud of gas and dust where new stars are forming.” Thank you, Amr!

What to look for in Orion the Hunter

First, look for the two brightest stars in Orion: Betelgeuse and Rigel. Rigel’s distance is approximately 860 light-years. However, the distance to Betelgeuse has been harder for scientists to determine. Its current estimate is about 700 light-years away, but uncertainties remain.

Betelgeuse dimmed for a while in late 2019, generating a fair amount of excitement, because Betelgeuse is a star on the brink of a supernova. However, the star has since returned to its normal brightness. So how bright does it look tonight?

Also, a recent study suggests Betelgeuse might not be one star, but two!

Next, take a moment to trace the Belt of Orion and the Sword that hangs from his belt. If one of the stars in the Sword looks blurry to you, that’s because you’re actually seeing the Orion Nebula. And if you use binoculars or a telescope to look at the Orion Nebula, you’ll start to see some shape in the gas and dust cloud.

View at EarthSky Community Photos. | Andy Dungan near Cotopaxi, Colorado, captured this telescopic view of the Orion Nebula on October 4, 2024. Andy wrote: “I recently took a pic of Orion [look here] using an Antlia RGB enhancer. This photo turned out much bluer. Both pics are fun and I think I like the bluer one better. Orion is such a wonderful object to explore.” Thank you, Andy!

Connections between the stars

While the stars of constellations often look like they should be physically related and gravitationally bound, they usually are not.

However, some of Orion’s most famous stars do have a connection. Several of the brightest stars in Orion are members of our local spiral arm, sometimes called the Orion Arm or sometimes the Orion Spur of the Milky Way. Our local spiral arm lies between the Sagittarius and Perseus Arms of the Milky Way.

Now consider those three prominent Belt stars. They appear fainter than Rigel or Betelgeuse, and, not surprisingly, they’re farther away. As a matter of fact, they’re all giant stars located in the Orion Arm. These stars’ names and approximate distances are Mintaka (1,200 light-years), Alnilam (2,000 light-years), and Alnitak (1,260 light-years). When you look at these three stars, know that you’re looking across vast space, and into our local arm of the Milky Way galaxy.

View larger. | Artist’s concept of part of the Milky Way galaxy. Our sun is located in the Orion Arm, or Orion Spur, of the Milky Way. Several bright stars in Orion, including Rigel, Betelgeuse, the three stars in Orion’s Belt, and the Orion Nebula, also reside in the Orion Arm. Image via R. Hurt/ Wikimedia Commons.

Bottom line: Orion the Hunter is one of the easiest constellations to identify thanks to Orion’s Belt, the three medium-bright stars in a short, straight row at his waist.

Why do stars seem brighter in winter?

The post Orion the Hunter is easy to spot in January first appeared on EarthSky.

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EarthSky founder Deborah Byrd wants you to come to know the constellation Orion the Hunter. It’s one of the most famous constellations because it’s easy to identify, with several noticeably bright and interesting stars. Plus, Orion can help you visualize your place in the Milky Way galaxy. What’s not to like? Click here for the video. Prefer to read? See below!

Tonight look for the constellation Orion the Hunter. It’s a constant companion on winter evenings in the Northern Hemisphere, and on summer nights in the Southern Hemisphere. Plus, it’s probably the easiest constellation to spot thanks to its distinctive Belt. Orion’s Belt consists of three medium-bright stars in a short, straight row at the Hunter’s waistline. So if you see any three equally bright stars in a row this evening, you’re probably looking at Orion. Do you want to be sure? There are two even brighter stars – one reddish and the other blue – on either side of the Belt stars.

2025 lunar calendars on sale now. Makes a great gift! Check it out here.

If you want to learn just one constellation … this is a good one! And it’s very easy constellation to spot. Those of us in the Northern Hemisphere see Orion the Hunter arcing across the southern sky on January evenings. Southern Hemisphere? Turn this chart upside-down, and look in your northern sky. To see a precise view from your location, try Stellarium Online.

When to look for Orion

As seen from mid-northern latitudes, you’ll find Orion in the southeast in the January early evening and shining high in the south by mid-to-late evening (around 9 to 10 p.m. local time, the time on your clock wherever you live). If you live at temperate latitudes south of the equator, you’ll see Orion high in your northern sky around that same hour.

View at EarthSky Community Photos. | Amr Abdulwahab created this composite image of the constellation Orion the Hunter on January 1, 2023, in H-alpha. That wavelength explains why you can see the great red loop around Orion known as Barnard’s Loop. Amr wrote: “Orion is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the oldest and most recognizable constellations, with its 3 main stars forming a distinctive ‘belt’ shape. These stars are named Alnitak, Alnilam and Mintaka. The constellation also features several bright stars, including Betelgeuse and Rigel, as well as the Orion Nebula, a bright cloud of gas and dust where new stars are forming.” Thank you, Amr!

What to look for in Orion the Hunter

First, look for the two brightest stars in Orion: Betelgeuse and Rigel. Rigel’s distance is approximately 860 light-years. However, the distance to Betelgeuse has been harder for scientists to determine. Its current estimate is about 700 light-years away, but uncertainties remain.

Betelgeuse dimmed for a while in late 2019, generating a fair amount of excitement, because Betelgeuse is a star on the brink of a supernova. However, the star has since returned to its normal brightness. So how bright does it look tonight?

Also, a recent study suggests Betelgeuse might not be one star, but two!

Next, take a moment to trace the Belt of Orion and the Sword that hangs from his belt. If one of the stars in the Sword looks blurry to you, that’s because you’re actually seeing the Orion Nebula. And if you use binoculars or a telescope to look at the Orion Nebula, you’ll start to see some shape in the gas and dust cloud.

View at EarthSky Community Photos. | Andy Dungan near Cotopaxi, Colorado, captured this telescopic view of the Orion Nebula on October 4, 2024. Andy wrote: “I recently took a pic of Orion [look here] using an Antlia RGB enhancer. This photo turned out much bluer. Both pics are fun and I think I like the bluer one better. Orion is such a wonderful object to explore.” Thank you, Andy!

Connections between the stars

While the stars of constellations often look like they should be physically related and gravitationally bound, they usually are not.

However, some of Orion’s most famous stars do have a connection. Several of the brightest stars in Orion are members of our local spiral arm, sometimes called the Orion Arm or sometimes the Orion Spur of the Milky Way. Our local spiral arm lies between the Sagittarius and Perseus Arms of the Milky Way.

Now consider those three prominent Belt stars. They appear fainter than Rigel or Betelgeuse, and, not surprisingly, they’re farther away. As a matter of fact, they’re all giant stars located in the Orion Arm. These stars’ names and approximate distances are Mintaka (1,200 light-years), Alnilam (2,000 light-years), and Alnitak (1,260 light-years). When you look at these three stars, know that you’re looking across vast space, and into our local arm of the Milky Way galaxy.

View larger. | Artist’s concept of part of the Milky Way galaxy. Our sun is located in the Orion Arm, or Orion Spur, of the Milky Way. Several bright stars in Orion, including Rigel, Betelgeuse, the three stars in Orion’s Belt, and the Orion Nebula, also reside in the Orion Arm. Image via R. Hurt/ Wikimedia Commons.

Bottom line: Orion the Hunter is one of the easiest constellations to identify thanks to Orion’s Belt, the three medium-bright stars in a short, straight row at his waist.

Why do stars seem brighter in winter?

The post Orion the Hunter is easy to spot in January first appeared on EarthSky.

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Cassiopeia and the Big Dipper in January skies

Cassiopeia and the Big Dipper revolve opposite each other around Polaris, the North Star. Depending on your location on the globe, you can see Cassiopeia and the Big Dipper if you look north in January. And if you look north before dawn, their positions will be reversed from this chart. To see a precise view from your location, try Stellarium Online. Chart via EarthSky.

Cassiopeia and the Big Dipper in the night sky

Tonight, look for the northern sky’s two most prominent sky patterns – the constellation Cassiopeia the Queen and the Big Dipper. Cassiopeia and the Big Dipper circle around Polaris, the North Star, once a day, every day. What’s more, they are opposite each other, one on either side of the North Star.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here..

Cassiopeia

At nightfall, the constellation Cassiopeia the Queen is easy to recognize in the northern sky. This constellation looks like a W or M and contains five moderately bright stars. Plus, the distinctive shape of Cassiopeia makes it very noticeable among the stars of the northern sky.

The Big Dipper

And, of course, Ursa Major the Greater Bear – which contains the Big Dipper asterism – is one of the most famous star patterns. At nightfall this month, Cassiopeia shines high in the north while the Dipper lurks low. In fact, they are always on opposite sides of the North Star. From the southern half of the U.S., the Big Dipper is partly or totally beneath the horizon this month in the evening hours. North of about 40 degrees north latitude (the latitude of Denver, Colorado, and Beijing, China), the Big Dipper always stays above the horizon (if your horizon is level). To see a precise view from your location, try Stellarium Online.

They circle around Polaris all night

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, captured this photo of Cassiopeia and the Big Dipper with the North Star, Polaris, between them. She wrote: “The stars twinkle bright over the Pacific Ocean horizon. There’s the North Star, or Polaris, between Cassiopeia the Queen and the Big Dipper.” Thanks, Cecille!

But remember, their positions change as the night passes, as the great carousel of stars wheels westward (counterclockwise) around Polaris, the North Star. You’ll notice Polaris resides halfway between Cassiopeia and the Big Dipper. As a result, they are like riders on opposite sides of a Ferris wheel. Thus, looking northward, they rotate counterclockwise around Polaris – the star that marks the sky’s north celestial pole – once a day. Then approximately every 12 hours, as Earth spins beneath the heavens, Cassiopeia and the Big Dipper trade places in the sky.

Thus, around midnight tonight, Cassiopeia circles directly west (left) of Polaris, whereas the Big Dipper sweeps to Polaris’ east (right). And then, before dawn tomorrow the Big Dipper climbs right above the North Star, while Cassiopeia swings directly below.

The Big Dipper and the W-shaped constellation Cassiopeia the Queen circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude and all latitudes farther north. Image via Wikimedia Commons (CC BY-SA 2.5).

Bottom line: Watch the celestial clock and its two great big hour hands – Cassiopeia and the Big Dipper – as they swing around the North Star each and every night!

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

The post Cassiopeia and the Big Dipper in January skies first appeared on EarthSky.

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Cassiopeia and the Big Dipper revolve opposite each other around Polaris, the North Star. Depending on your location on the globe, you can see Cassiopeia and the Big Dipper if you look north in January. And if you look north before dawn, their positions will be reversed from this chart. To see a precise view from your location, try Stellarium Online. Chart via EarthSky.

Cassiopeia and the Big Dipper in the night sky

Tonight, look for the northern sky’s two most prominent sky patterns – the constellation Cassiopeia the Queen and the Big Dipper. Cassiopeia and the Big Dipper circle around Polaris, the North Star, once a day, every day. What’s more, they are opposite each other, one on either side of the North Star.

EarthSky lunar calendars are back in stock! And we’re guaranteed to sell out, so get one while you can. Your support means the world to us and allows us to keep going. Purchase here..

Cassiopeia

At nightfall, the constellation Cassiopeia the Queen is easy to recognize in the northern sky. This constellation looks like a W or M and contains five moderately bright stars. Plus, the distinctive shape of Cassiopeia makes it very noticeable among the stars of the northern sky.

The Big Dipper

And, of course, Ursa Major the Greater Bear – which contains the Big Dipper asterism – is one of the most famous star patterns. At nightfall this month, Cassiopeia shines high in the north while the Dipper lurks low. In fact, they are always on opposite sides of the North Star. From the southern half of the U.S., the Big Dipper is partly or totally beneath the horizon this month in the evening hours. North of about 40 degrees north latitude (the latitude of Denver, Colorado, and Beijing, China), the Big Dipper always stays above the horizon (if your horizon is level). To see a precise view from your location, try Stellarium Online.

They circle around Polaris all night

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, captured this photo of Cassiopeia and the Big Dipper with the North Star, Polaris, between them. She wrote: “The stars twinkle bright over the Pacific Ocean horizon. There’s the North Star, or Polaris, between Cassiopeia the Queen and the Big Dipper.” Thanks, Cecille!

But remember, their positions change as the night passes, as the great carousel of stars wheels westward (counterclockwise) around Polaris, the North Star. You’ll notice Polaris resides halfway between Cassiopeia and the Big Dipper. As a result, they are like riders on opposite sides of a Ferris wheel. Thus, looking northward, they rotate counterclockwise around Polaris – the star that marks the sky’s north celestial pole – once a day. Then approximately every 12 hours, as Earth spins beneath the heavens, Cassiopeia and the Big Dipper trade places in the sky.

Thus, around midnight tonight, Cassiopeia circles directly west (left) of Polaris, whereas the Big Dipper sweeps to Polaris’ east (right). And then, before dawn tomorrow the Big Dipper climbs right above the North Star, while Cassiopeia swings directly below.

The Big Dipper and the W-shaped constellation Cassiopeia the Queen circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude and all latitudes farther north. Image via Wikimedia Commons (CC BY-SA 2.5).

Bottom line: Watch the celestial clock and its two great big hour hands – Cassiopeia and the Big Dipper – as they swing around the North Star each and every night!

Easily locate stars and constellations during any day and time with EarthSky’s Planisphere.

The post Cassiopeia and the Big Dipper in January skies first appeared on EarthSky.

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New species of giant sea bug named for Darth Vader

The head of the newly discovered giant sea bug species Bathynomus vaderi. It looks like Darth Vader’s helmet and mask, hence its name. Image by Nguyen Thanh Son/ Pensoft Publishers.

A few days ago, in a sea far, far away . . . A team of scientists discovered a new species of giant sea bug off the coast of Vietnam. The team of researchers, from Singapore, Indonesia and Vietnam, announced the discovery on January 14, 2025. The newly discovered species is a type of giant isopod. This crustacean is 12.8 inches (32.5 cm) long. But it’s not just the size that’s impressive. Its head closely resembles the iconic helmet of Darth Vader, the most famous Sith Lord from the Star Wars franchise. Hence its name, Bathynomus vaderi.

The researchers published their peer-reviewed study on January 14, 2025, in the open-access journal ZooKeys.

Discovery of the new species of giant sea bug

Giant isopods can reach more than 11.8 inches (30 cm) in length and weigh more than a kilogram. Impressive! So, you might wonder how such a large creature has not been discovered until now.

The curious thing is that Vietnamese fishermen have been fishing and consuming giant isopods for a long time. In fact, until 2017, they were sold as a bycatch product, at low prices. However, in recent years, the media has drawn public attention to this unusual creature. Some people even claim this crustacean is tastier than lobster.

In March 2022, staff at the University of Hanoi, the capital of Vietnam, purchased four giant isopod individuals and sent two of them to Peter Ng of the Lee Kong Chian Natural History Museum in Singapore for identification.

Peter Ng runs a crustacean laboratory in Singapore and has worked on deep-sea fauna from many parts of Asia. He recruited Conni M. Sidabalok of Indonesia’s National Agency for Research and Innovation. Then, Nguyen Thanh Son of Vietnam National University, a resident crustacean researcher there, joined the team.

Giant isopods can reach more than 11.8 inches (30 cm) in length and weigh more than 2.2 pounds (1 kg). This is Dr. Nguyen Thanh Son holding a specimen of new species Bathynomus vaderi at VNU University of Science, Hanoi, Vietnam. Image via Tran Anh Duc/ Pensoft Publishers, sent exclusively for EarthSky.

The Dark Side of the ocean

In early 2023, the researchers realized they had specimens of a previously undescribed species of the Bathynomus genus. They have finally named the new creature Bathynomus vaderi, in honor of Darth Vader.

There are about 10,000 species of isopods in the world. The genus Bathynomus comprises about 20 species. They can typically be found in the cold, deep waters of the Atlantic, Pacific and Indian Oceans.

In the case of the newly discovered species Bathynomus vaderi, it has only been found near the Spratly Islands in Vietnam. But further research is likely to confirm its presence in other parts of the South China Sea.

According to the researchers:

The discovery of a species as strange as Bathynomus vaderi in Vietnam highlights just how poorly we understand the deep-sea environment. That a species as large as this could have stayed hidden for so long reminds us just how much work we still need to do to find out what lives in Southeast Asian waters.

Specimen of Bathynomus vaderi. Image via Nguyen Thanh Son. Pensoft Publishers sent this image exclusively for EarthSky.

Bottom line: Are you a fan of Star Wars? If Darth Vader is your favorite character, you will love this news! A recently discovered species of giant sea bug received was named for this iconic character. Find out why here.

Source: A new species of supergiant Bathynomus A. Milne-Edwards, 1879 (Crustacea, Isopoda, Cirolanidae) from Vietnam, with notes on the taxonomy of Bathynomus jamesi Kou, Chen & Li, 2017

Via Pensoft Publishers

Read more: The adorable leaf sheep sea slug: Lifeform of the week

Read more: Lifeform of the week: Axolotls, the key to eternal youth?

The post New species of giant sea bug named for Darth Vader first appeared on EarthSky.

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The head of the newly discovered giant sea bug species Bathynomus vaderi. It looks like Darth Vader’s helmet and mask, hence its name. Image by Nguyen Thanh Son/ Pensoft Publishers.

A few days ago, in a sea far, far away . . . A team of scientists discovered a new species of giant sea bug off the coast of Vietnam. The team of researchers, from Singapore, Indonesia and Vietnam, announced the discovery on January 14, 2025. The newly discovered species is a type of giant isopod. This crustacean is 12.8 inches (32.5 cm) long. But it’s not just the size that’s impressive. Its head closely resembles the iconic helmet of Darth Vader, the most famous Sith Lord from the Star Wars franchise. Hence its name, Bathynomus vaderi.

The researchers published their peer-reviewed study on January 14, 2025, in the open-access journal ZooKeys.

Discovery of the new species of giant sea bug

Giant isopods can reach more than 11.8 inches (30 cm) in length and weigh more than a kilogram. Impressive! So, you might wonder how such a large creature has not been discovered until now.

The curious thing is that Vietnamese fishermen have been fishing and consuming giant isopods for a long time. In fact, until 2017, they were sold as a bycatch product, at low prices. However, in recent years, the media has drawn public attention to this unusual creature. Some people even claim this crustacean is tastier than lobster.

In March 2022, staff at the University of Hanoi, the capital of Vietnam, purchased four giant isopod individuals and sent two of them to Peter Ng of the Lee Kong Chian Natural History Museum in Singapore for identification.

Peter Ng runs a crustacean laboratory in Singapore and has worked on deep-sea fauna from many parts of Asia. He recruited Conni M. Sidabalok of Indonesia’s National Agency for Research and Innovation. Then, Nguyen Thanh Son of Vietnam National University, a resident crustacean researcher there, joined the team.

Giant isopods can reach more than 11.8 inches (30 cm) in length and weigh more than 2.2 pounds (1 kg). This is Dr. Nguyen Thanh Son holding a specimen of new species Bathynomus vaderi at VNU University of Science, Hanoi, Vietnam. Image via Tran Anh Duc/ Pensoft Publishers, sent exclusively for EarthSky.

The Dark Side of the ocean

In early 2023, the researchers realized they had specimens of a previously undescribed species of the Bathynomus genus. They have finally named the new creature Bathynomus vaderi, in honor of Darth Vader.

There are about 10,000 species of isopods in the world. The genus Bathynomus comprises about 20 species. They can typically be found in the cold, deep waters of the Atlantic, Pacific and Indian Oceans.

In the case of the newly discovered species Bathynomus vaderi, it has only been found near the Spratly Islands in Vietnam. But further research is likely to confirm its presence in other parts of the South China Sea.

According to the researchers:

The discovery of a species as strange as Bathynomus vaderi in Vietnam highlights just how poorly we understand the deep-sea environment. That a species as large as this could have stayed hidden for so long reminds us just how much work we still need to do to find out what lives in Southeast Asian waters.

Specimen of Bathynomus vaderi. Image via Nguyen Thanh Son. Pensoft Publishers sent this image exclusively for EarthSky.

Bottom line: Are you a fan of Star Wars? If Darth Vader is your favorite character, you will love this news! A recently discovered species of giant sea bug received was named for this iconic character. Find out why here.

Source: A new species of supergiant Bathynomus A. Milne-Edwards, 1879 (Crustacea, Isopoda, Cirolanidae) from Vietnam, with notes on the taxonomy of Bathynomus jamesi Kou, Chen & Li, 2017

Via Pensoft Publishers

Read more: The adorable leaf sheep sea slug: Lifeform of the week

Read more: Lifeform of the week: Axolotls, the key to eternal youth?

The post New species of giant sea bug named for Darth Vader first appeared on EarthSky.

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Freezing rain: All about this dangerous ice

Freezing rain leaves a thick coat of ice on a tree branch. Image via Wikimedia Commons.

Freezing rain

Freezing rain is simply rain that falls through a shallow layer of cold temperatures at or below 32 degrees Fahrenheit (0 degrees Celsius) near the surface. When this rain becomes super-cooled, it can freeze on contact with roads, bridges, trees, power lines and vehicles. When freezing rain accumulates, it can add a lot of weight on trees – a quarter of an inch of ice can add 500 pounds of weight – which can bring trees down and result in numerous power outages and damage to homes.

Freezing rain is typically the weather threat that creates the most car accidents, injuries and deaths in winter storms. Many people can drive in the rain and snow, but when the roads become icy, it is almost impossible to drive. Severe ice storms can shut down large cities, result in thousands of power outages, and the most severe ones can also become billion-dollar disasters (rare).

This chart shows how snow melts as it falls through the air and becomes freezing rain when it nears the surface. Image via NWS.

Available now! 2025 EarthSky lunar calendar. A unique and beautiful poster-sized calendar showing phases of the moon every night of the year! And it makes a great gift.

Different types of winter precipitation

It is important to know the difference between snow, sleet and freezing rain.

1) Snow forms when the entire layer of air is sub-freezing. Snow consists of ice crystals and is white and fluffy.

2) Sleet forms when the layer of sub-freezing air is fairly deep at 3,000 to 4,000 feet. This allows time for the water droplet to freeze into a tiny piece of ice and become sleet as it falls to the surface. Precipitation in the wintertime that falls as tiny ice pellets is sleet. Hail is only associated with strong thunderstorms and are larger in size and can cause damage.

3) Freezing rain forms when the sub-freezing layer is very shallow. At 2,000 feet from the surface, temperatures are above freezing, so any precipitation that falls is liquid. Once rain hits that shallow, cold air near the surface, it freezes on contact with any object.

Shallow, cold air at the surface can sometimes occur thanks to cold air damming. Cold air damming, abbreviated as CAD, is where a low-level cold air mass becomes trapped topographically. These events can be very common near or around mountain regions, and is known to occur across the eastern United States thanks to the Appalachian Mountains. Some of the worst ice storms to form were thanks to this CAD effect that is also known as the “wedge”. This term is used because shallow cold air is wedged down the Appalachian Mountains thanks to a ridge of high pressure typically located across New England, eastern Canada, or the Mid-Atlantic.

This chart shows temperatures and types of winter precipitation. They are snow, sleet, freezing rain and rain. Image via NWS.

Freezing rain causes major problems

When it comes to freezing rain, it is the weight of the ice on the trees that causes problems. They can fall over and crush cars, houses and power lines. According to Steve Nix, brittle tree species typically take the brunt of heavy icing. Trees such as poplars, silver maples, birches, willows and hack-berries are more likely to break and fall over due to the weight of the ice. One of the big reasons these trees break and fall over first is because they are fast growers. They also develop weak, V-shaped crotches that can easily split apart under the added weight of ice.

View at EarthSky Community Photos. | Carol Henderson captured freezing rain on this bush in Durham, North Carolina, on January 10, 2025. Thank you, Carol!

View at EarthSky Community Photos. | Nina Gorenstein in West Lafayette, Indiana, captured this photo of ice coating the neighborhood. She wrote: “The New Year began with wind and freezing rain alerts. Ice crust and frozen rain drops appeared on branches of trees, wires, borders of roofs. The tiny icicles are so evenly distributed!” Thanks, Nina!

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Bottom line: Freezing rain is simply rain that falls into a shallow layer of cold temperatures that is below freezing. When this super-cooled droplet hits an object, it then freezes and becomes ice. Freezing ice is dangerous and can down power lines, paralyze cities, bring down trees and cause serious accidents.

Read more: Too cold to snow? Is that possible?

The post Freezing rain: All about this dangerous ice first appeared on EarthSky.

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Freezing rain leaves a thick coat of ice on a tree branch. Image via Wikimedia Commons.

Freezing rain

Freezing rain is simply rain that falls through a shallow layer of cold temperatures at or below 32 degrees Fahrenheit (0 degrees Celsius) near the surface. When this rain becomes super-cooled, it can freeze on contact with roads, bridges, trees, power lines and vehicles. When freezing rain accumulates, it can add a lot of weight on trees – a quarter of an inch of ice can add 500 pounds of weight – which can bring trees down and result in numerous power outages and damage to homes.

Freezing rain is typically the weather threat that creates the most car accidents, injuries and deaths in winter storms. Many people can drive in the rain and snow, but when the roads become icy, it is almost impossible to drive. Severe ice storms can shut down large cities, result in thousands of power outages, and the most severe ones can also become billion-dollar disasters (rare).

This chart shows how snow melts as it falls through the air and becomes freezing rain when it nears the surface. Image via NWS.

Available now! 2025 EarthSky lunar calendar. A unique and beautiful poster-sized calendar showing phases of the moon every night of the year! And it makes a great gift.

Different types of winter precipitation

It is important to know the difference between snow, sleet and freezing rain.

1) Snow forms when the entire layer of air is sub-freezing. Snow consists of ice crystals and is white and fluffy.

2) Sleet forms when the layer of sub-freezing air is fairly deep at 3,000 to 4,000 feet. This allows time for the water droplet to freeze into a tiny piece of ice and become sleet as it falls to the surface. Precipitation in the wintertime that falls as tiny ice pellets is sleet. Hail is only associated with strong thunderstorms and are larger in size and can cause damage.

3) Freezing rain forms when the sub-freezing layer is very shallow. At 2,000 feet from the surface, temperatures are above freezing, so any precipitation that falls is liquid. Once rain hits that shallow, cold air near the surface, it freezes on contact with any object.

Shallow, cold air at the surface can sometimes occur thanks to cold air damming. Cold air damming, abbreviated as CAD, is where a low-level cold air mass becomes trapped topographically. These events can be very common near or around mountain regions, and is known to occur across the eastern United States thanks to the Appalachian Mountains. Some of the worst ice storms to form were thanks to this CAD effect that is also known as the “wedge”. This term is used because shallow cold air is wedged down the Appalachian Mountains thanks to a ridge of high pressure typically located across New England, eastern Canada, or the Mid-Atlantic.

This chart shows temperatures and types of winter precipitation. They are snow, sleet, freezing rain and rain. Image via NWS.

Freezing rain causes major problems

When it comes to freezing rain, it is the weight of the ice on the trees that causes problems. They can fall over and crush cars, houses and power lines. According to Steve Nix, brittle tree species typically take the brunt of heavy icing. Trees such as poplars, silver maples, birches, willows and hack-berries are more likely to break and fall over due to the weight of the ice. One of the big reasons these trees break and fall over first is because they are fast growers. They also develop weak, V-shaped crotches that can easily split apart under the added weight of ice.

View at EarthSky Community Photos. | Carol Henderson captured freezing rain on this bush in Durham, North Carolina, on January 10, 2025. Thank you, Carol!

View at EarthSky Community Photos. | Nina Gorenstein in West Lafayette, Indiana, captured this photo of ice coating the neighborhood. She wrote: “The New Year began with wind and freezing rain alerts. Ice crust and frozen rain drops appeared on branches of trees, wires, borders of roofs. The tiny icicles are so evenly distributed!” Thanks, Nina!

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Bottom line: Freezing rain is simply rain that falls into a shallow layer of cold temperatures that is below freezing. When this super-cooled droplet hits an object, it then freezes and becomes ice. Freezing ice is dangerous and can down power lines, paralyze cities, bring down trees and cause serious accidents.

Read more: Too cold to snow? Is that possible?

The post Freezing rain: All about this dangerous ice first appeared on EarthSky.

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Spiders can smell using their legs! The secret uncovered

A new discovery said spiders can smell using their legs. Scientists from Lund University in Sweden and the University of Greifswald in Germany analyzed wasp spiders (Argiope bruennichi) and discovered olfactory hairs on their legs. Image via Lucas van Oort/ Unsplash.

Spiders can smell using their legs

A team of researchers from Lund University in Sweden and the University of Greifswald in Germany found some male spiders use olfactory hairs on their legs to distantly detect sexual pheromones that female spiders release. These olfactory hairs had been overlooked until now. The Conversation wrote an article about the discovery on January 7, 2024.

There are more than 45,000 species of spiders in the world. And these creatures have inhabited Earth for 400 billion years. However, although scientists knew these eight-legged beings could detect odors, they didn’t know how, exactly. The researchers published their study in the journal Proceedings of the National Academy of Sciences on January 6, 2025.

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

How did they make the discovery?

Spiders do not have nostrils like mammals. Neither do they have antennae like insects, which have olfactory hairs called wall-pore sensilla on their antennae. Insects use these hairs to smell. Previous studies suggested spiders do not have wall-pore sensilla.

However, the researchers in the new study looked at male wasp spiders (Argiope bruennichi). They found the males do indeed have wall-pore sensilla on their legs. You could say these males smell with their legs.

Also, this is not an ability specific to wasp spiders, but rather it’s a capacity prevalent for all (male) spiders.

Some adult male spiders have olfactory hairs called wall-pore sensilla on the upper part of their legs. These hairs detect sexual pheromones that females produce. Image via Mohammad Belal Talukder, Carsten H. G. Müller, Dan-Dan Zhang and Gabriele B. Uhl/ PNAS.

What is the sense of smell like in spiders?

Scientists studied both male and female spiders of the Argiope bruennichi species. The team used high-resolution scanning electron microscopy and discovered something fascinating. Male spiders have wall-pore sensilla on all eight legs. What’s more, these sensilla are different from the sensilla found in insects and even other arthropods.

The wall-pore sensilla in males are located on the top of the legs, that is, close to the body. These areas almost never come into contact with a surface when spiders move. And, interestingly, the wall-pore sensilla have only been found in adult males. Neither young males nor females have these hairs.

External appearance and cross-sections of wall-pore sensilla in Argiope bruennichi males. Image via Mohammad Belal Talukder, Carsten H. G. Müller, Dan-Dan Zhang and Gabriele B. Uhl/ PNAS.

What about female spiders?

Scientists believe male spiders use wall-pore sensilla to detect airborne sex pheromones released by females. This is supposedly how these males find mates. Female spiders release gaseous pheromones that attract males from a distance.

To prove their theory, the scientists placed male spiders under a microscope and connected electrodes to the wall-pore sensilla. When the male spiders were exposed to a pheromone compound, even in a very small amount, the spiders responded with a burst of activity in neuronal cells from the sensilla.

The scientists observed how their olfactory sensilla are incredibly sensitive, much more so than the most sensitive sex pheromone communication systems in insects.

What’s next?

The scientists analyzed 19 other spider species and found that most have wall-pore sensilla and that they are specific to males.

However, other spider species, such as the basal trapdoor spider, do not have these olfactory hairs. The wall-pore sensilla evolved independently within spiders and were lost in some lineages.

Many questions remain to be answered by future studies: Can female spiders and young males smell in another way? How many other species have these olfactory hairs? Can species that do not have these hairs smell in another way? Can spiders detect other chemicals besides sexual pheromones?

It will be exciting to see what new discoveries can tell us.

Bottom line: Scientists knew spiders could smell, but they didn’t know how, exactly. Until now. Spiders can smell using their legs. But, interestingly, young male spiders and female spiders don’t possess this ability. Find out why, here.

Via The Conversation

Source: PNAS: Olfaction with legs—Spiders use wall-pore sensilla for pheromone detection

Read more: Here are 3 amazing feats of spiders

Read more: Lifeform of the week: Scorpions

The post Spiders can smell using their legs! The secret uncovered first appeared on EarthSky.

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A new discovery said spiders can smell using their legs. Scientists from Lund University in Sweden and the University of Greifswald in Germany analyzed wasp spiders (Argiope bruennichi) and discovered olfactory hairs on their legs. Image via Lucas van Oort/ Unsplash.

Spiders can smell using their legs

A team of researchers from Lund University in Sweden and the University of Greifswald in Germany found some male spiders use olfactory hairs on their legs to distantly detect sexual pheromones that female spiders release. These olfactory hairs had been overlooked until now. The Conversation wrote an article about the discovery on January 7, 2024.

There are more than 45,000 species of spiders in the world. And these creatures have inhabited Earth for 400 billion years. However, although scientists knew these eight-legged beings could detect odors, they didn’t know how, exactly. The researchers published their study in the journal Proceedings of the National Academy of Sciences on January 6, 2025.

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

How did they make the discovery?

Spiders do not have nostrils like mammals. Neither do they have antennae like insects, which have olfactory hairs called wall-pore sensilla on their antennae. Insects use these hairs to smell. Previous studies suggested spiders do not have wall-pore sensilla.

However, the researchers in the new study looked at male wasp spiders (Argiope bruennichi). They found the males do indeed have wall-pore sensilla on their legs. You could say these males smell with their legs.

Also, this is not an ability specific to wasp spiders, but rather it’s a capacity prevalent for all (male) spiders.

Some adult male spiders have olfactory hairs called wall-pore sensilla on the upper part of their legs. These hairs detect sexual pheromones that females produce. Image via Mohammad Belal Talukder, Carsten H. G. Müller, Dan-Dan Zhang and Gabriele B. Uhl/ PNAS.

What is the sense of smell like in spiders?

Scientists studied both male and female spiders of the Argiope bruennichi species. The team used high-resolution scanning electron microscopy and discovered something fascinating. Male spiders have wall-pore sensilla on all eight legs. What’s more, these sensilla are different from the sensilla found in insects and even other arthropods.

The wall-pore sensilla in males are located on the top of the legs, that is, close to the body. These areas almost never come into contact with a surface when spiders move. And, interestingly, the wall-pore sensilla have only been found in adult males. Neither young males nor females have these hairs.

External appearance and cross-sections of wall-pore sensilla in Argiope bruennichi males. Image via Mohammad Belal Talukder, Carsten H. G. Müller, Dan-Dan Zhang and Gabriele B. Uhl/ PNAS.

What about female spiders?

Scientists believe male spiders use wall-pore sensilla to detect airborne sex pheromones released by females. This is supposedly how these males find mates. Female spiders release gaseous pheromones that attract males from a distance.

To prove their theory, the scientists placed male spiders under a microscope and connected electrodes to the wall-pore sensilla. When the male spiders were exposed to a pheromone compound, even in a very small amount, the spiders responded with a burst of activity in neuronal cells from the sensilla.

The scientists observed how their olfactory sensilla are incredibly sensitive, much more so than the most sensitive sex pheromone communication systems in insects.

What’s next?

The scientists analyzed 19 other spider species and found that most have wall-pore sensilla and that they are specific to males.

However, other spider species, such as the basal trapdoor spider, do not have these olfactory hairs. The wall-pore sensilla evolved independently within spiders and were lost in some lineages.

Many questions remain to be answered by future studies: Can female spiders and young males smell in another way? How many other species have these olfactory hairs? Can species that do not have these hairs smell in another way? Can spiders detect other chemicals besides sexual pheromones?

It will be exciting to see what new discoveries can tell us.

Bottom line: Scientists knew spiders could smell, but they didn’t know how, exactly. Until now. Spiders can smell using their legs. But, interestingly, young male spiders and female spiders don’t possess this ability. Find out why, here.

Via The Conversation

Source: PNAS: Olfaction with legs—Spiders use wall-pore sensilla for pheromone detection

Read more: Here are 3 amazing feats of spiders

Read more: Lifeform of the week: Scorpions

The post Spiders can smell using their legs! The secret uncovered first appeared on EarthSky.

from EarthSky https://ift.tt/whODAcE

Little Red Dots might indicate ancient, growing black holes

Here are a few of many mysterious Little Red Dots, that the Webb space telescope spotted in parts of the sky. They have perplexed researchers since astronomers first noticed them, in 2022. But, having compiled one of the largest samples of Little Red Dots yet, a team of researchers says a large fraction of them are likely galaxies with black holes growing at their centers. Image via NASA, ESA, CSA, STScI, Dale Kocevski (Colby College).

NASA published this article on January 14, 2025. Edits by EarthSky.

What are Webb’s mysterious Little Red Dots?

In December 2022, less than six months after commencing science operations, NASA’s James Webb Space Telescope revealed something never seen before. It discovered an abundance of tiny red objects scattered across the sky. Scientists dubbed them ‘Little Red Dots.’ Since then, researchers have been perplexed by their nature, the reason for their color and what they convey about the early universe.

Now, a team of astronomers has compiled one of the largest samples of Little Red Dots to date. Nearly all of them existed during the first 1.5 billion years after the Big Bang. And they said on January 14, 2025, that a large fraction of the Little Red Dots in their sample are likely galaxies with supermassive black holes growing at their centers.

2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!

A peek into early black hole growth?

By combing through data from several publicly available surveys, the researchers assembled a huge sample of these Little Red Dots. And they found the distribution of these objects across time to be intriguing. The Little Red Dots appear to emerge in large numbers around 600 million years after the Big Bang. They then underwent a rapid decline in quantity around 1.5 billion years after the Big Bang.

And they found that about 70 percent of the targets showed evidence for gas rapidly orbiting 2 million miles per hour (900 kilometers per second). That’s what you’d expect from an accretion disk around a supermassive black hole. So this suggests many Little Red Dots are accreting black holes, also known as active galactic nuclei (AGN).

Steven Finkelstein, a co-author of the study, said:

The most exciting thing for me is the redshift distributions. These really red, high-redshift sources basically stop existing at a certain point after the big bang. If they are growing black holes, and we think at least 70 percent of them are, this hints at an era of obscured [by gas and dust] black hole growth in the early universe.

A montage of some of the intriguing Little Red Dots Webb has spotted in the early universe. Image via J. Matthee et al., 2024 (CC BY 4.0).

Contrary to headlines, cosmology isn’t broken

When astronomers first discovered the Little Red Dots, some suggested that cosmology was ‘broken.’ If all of the light coming from these objects was from stars, it implied that some galaxies had grown so big, so fast, that theories could not account for them.

But the team’s research suggests that much of the light coming from these objects is from accreting black holes, not from stars. Fewer stars means smaller, more lightweight galaxies existing theories can explain.

Anthony Taylor, a co-author of the study, surmised:

This is how you solve the universe-breaking problem.

But questions remain around Little Red Dots

But the Little Red Dots evoke even more questions. For example, it’s still not clear why they don’t appear at lower redshifts. That is, more recently in the universe’s history. One possible answer is inside-out growth. As star formation within a galaxy expands outward from the nucleus, supernovae deposit less gas near the accreting black hole. It then becomes less obscured. So the black hole eventually sheds its gas cocoon, becoming bluer and less red. It therefore stops appearing as a Little Red Dot.

Additionally, Little Red Dots are not bright in X-ray light, unlike most black holes we see in the more recent universe. However, astronomers know that at certain gas densities, X-ray photons can become trapped. This reduces the amount of X-ray emission. Therefore, this quality of Little Red Dots could support the theory that these are heavily obscured black holes.

The team is taking multiple approaches to understand the nature of Little Red Dots. This includes examining the mid-infrared properties of their sample, and looking more broadly for accreting black holes to see how many fit the Little Red Dots criteria. Obtaining deeper follow-up observations will also be beneficial for solving this currently ‘open case’ about the mysterious Little Red Dots.

The researchers presented these results in a press conference at the 245th meeting of the American Astronomical Society in National Harbor, Maryland. They have also been submitted for publication in The Astrophysical Journal.

Bottom line: Researchers studying the mysterious Little Red Dots discovered by Webb have found evidence that they could be ancient galaxies with supermassive black holes growing at their centers.

Via NASA

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

The post Little Red Dots might indicate ancient, growing black holes first appeared on EarthSky.

from EarthSky https://ift.tt/30csl4p

Here are a few of many mysterious Little Red Dots, that the Webb space telescope spotted in parts of the sky. They have perplexed researchers since astronomers first noticed them, in 2022. But, having compiled one of the largest samples of Little Red Dots yet, a team of researchers says a large fraction of them are likely galaxies with black holes growing at their centers. Image via NASA, ESA, CSA, STScI, Dale Kocevski (Colby College).

NASA published this article on January 14, 2025. Edits by EarthSky.

What are Webb’s mysterious Little Red Dots?

In December 2022, less than six months after commencing science operations, NASA’s James Webb Space Telescope revealed something never seen before. It discovered an abundance of tiny red objects scattered across the sky. Scientists dubbed them ‘Little Red Dots.’ Since then, researchers have been perplexed by their nature, the reason for their color and what they convey about the early universe.

Now, a team of astronomers has compiled one of the largest samples of Little Red Dots to date. Nearly all of them existed during the first 1.5 billion years after the Big Bang. And they said on January 14, 2025, that a large fraction of the Little Red Dots in their sample are likely galaxies with supermassive black holes growing at their centers.

2025 EarthSky lunar calendar is available now. A unique and beautiful poster-sized calendar with phases of the moon for every night of the year. Get yours today!

A peek into early black hole growth?

By combing through data from several publicly available surveys, the researchers assembled a huge sample of these Little Red Dots. And they found the distribution of these objects across time to be intriguing. The Little Red Dots appear to emerge in large numbers around 600 million years after the Big Bang. They then underwent a rapid decline in quantity around 1.5 billion years after the Big Bang.

And they found that about 70 percent of the targets showed evidence for gas rapidly orbiting 2 million miles per hour (900 kilometers per second). That’s what you’d expect from an accretion disk around a supermassive black hole. So this suggests many Little Red Dots are accreting black holes, also known as active galactic nuclei (AGN).

Steven Finkelstein, a co-author of the study, said:

The most exciting thing for me is the redshift distributions. These really red, high-redshift sources basically stop existing at a certain point after the big bang. If they are growing black holes, and we think at least 70 percent of them are, this hints at an era of obscured [by gas and dust] black hole growth in the early universe.

A montage of some of the intriguing Little Red Dots Webb has spotted in the early universe. Image via J. Matthee et al., 2024 (CC BY 4.0).

Contrary to headlines, cosmology isn’t broken

When astronomers first discovered the Little Red Dots, some suggested that cosmology was ‘broken.’ If all of the light coming from these objects was from stars, it implied that some galaxies had grown so big, so fast, that theories could not account for them.

But the team’s research suggests that much of the light coming from these objects is from accreting black holes, not from stars. Fewer stars means smaller, more lightweight galaxies existing theories can explain.

Anthony Taylor, a co-author of the study, surmised:

This is how you solve the universe-breaking problem.

But questions remain around Little Red Dots

But the Little Red Dots evoke even more questions. For example, it’s still not clear why they don’t appear at lower redshifts. That is, more recently in the universe’s history. One possible answer is inside-out growth. As star formation within a galaxy expands outward from the nucleus, supernovae deposit less gas near the accreting black hole. It then becomes less obscured. So the black hole eventually sheds its gas cocoon, becoming bluer and less red. It therefore stops appearing as a Little Red Dot.

Additionally, Little Red Dots are not bright in X-ray light, unlike most black holes we see in the more recent universe. However, astronomers know that at certain gas densities, X-ray photons can become trapped. This reduces the amount of X-ray emission. Therefore, this quality of Little Red Dots could support the theory that these are heavily obscured black holes.

The team is taking multiple approaches to understand the nature of Little Red Dots. This includes examining the mid-infrared properties of their sample, and looking more broadly for accreting black holes to see how many fit the Little Red Dots criteria. Obtaining deeper follow-up observations will also be beneficial for solving this currently ‘open case’ about the mysterious Little Red Dots.

The researchers presented these results in a press conference at the 245th meeting of the American Astronomical Society in National Harbor, Maryland. They have also been submitted for publication in The Astrophysical Journal.

Bottom line: Researchers studying the mysterious Little Red Dots discovered by Webb have found evidence that they could be ancient galaxies with supermassive black holes growing at their centers.

Via NASA

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

The post Little Red Dots might indicate ancient, growing black holes first appeared on EarthSky.

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Meet the Winter Circle, aka the Winter Hexagon

The Winter Circle or Winter Hexagon

The Winter Circle (or Hexagon) is a large circular pattern, made of some of the brightest stars in the Northern Hemisphere’s winter sky (or the Southern Hemisphere’s summer sky). It isn’t a constellation. It’s an asterism, or prominent group of stars that form a noticeable pattern. In addition, the Winter Circle has a smaller asterism inside it, called the Winter Triangle.

Plus in 2025 the planet Jupiter lies inside the Winter Circle and Mars is nearby.

The Winter Circle (or Winter Hexagon) isn’t a constellation. It’s an asterism, made of bright stars in the winter evening sky for the Northern Hemisphere (and summer sky for the Southern Hemisphere). It covers a large portion of the sky. Chart via EarthSky.

Meet the Winter Circle

Strictly speaking, you’ll see this circular pattern of 1st-magnitude stars – the brightest stars in our sky – from six different constellations: Rigel in Orion the Hunter, Aldebaran in Taurus the Bull, Capella in Auriga the Charioteer, Pollux (and its forever companion Castor) in Gemini the Twins, Procyon in Canis Minor the Lesser Dog and Sirius in Canis Major the Greater Dog. Also, an additional 1st-magnitude star, Betelgeuse in Orion the Hunter, lies toward the center of the Circle.

The Circle is big

The Winter Circle is big! To get an idea of the it’s humongous size, the span from the southernmost star, Sirius, to the northernmost star, Capella, covers about 1/3 of the dome of the sky.

Image of the evening sky on December 31, 2024, taken with an allsky camera. The Winter Hexagon takes up a large portion of the sky. Plus in 2025, the planets Jupiter and Mars are nearby. Image via WyoAstro observatory.

2025 lunar calendars on sale now. Makes a great gift! Check it out here.

When is the Winter Circle (or Hexagon) visible?

So, like all stars, those in the Winter Circle rise and set some four minutes earlier with each passing night. Indeed, by late January, the Winter Circle will have risen high enough above the northeastern horizon so it’s visible by about 7 p.m. local time. Then, if you look around midnight, the Winter Circle will be high above the southern horizon. And later, after about 3 a.m. local time, it sinks toward the southwestern horizon, with some of it setting in the west before sunrise.

Then, in late February and early March, the Winter Circle is in your southern sky at nightfall and early evening.

View at EarthSky Community Photos. | Jose Zarcos Palma in Mina Sao Domingo, Mertola, Portugal, took this image of the Winter Circle on December 26, 2022. Jose wrote: “I planned this composition to catch the great Winter Circle in an early stage of its ascension just behind the abandoned mining ruins of Achada do Gamo. We can clearly see Sirius in the Canis Major the Greater Dog near the chimney on the right side, just below Orion the Hunter. On top of the image, the planet Mars is near Aldebaran in Taurus the Bull.” Thank you, Jose!

Finding the Winter Circle

First, to find the Winter Circle (or Hexagon), find the easily recognizable constellation of Orion the Hunter. Indeed, its three belt stars give it away. Then, look for the bright bluish star to the lower right. This star is Rigel, the southwest corner of the Winter Circle and the first of the six stars in the Circle. By the way, Rigel is the brightest star in Orion and the seventh brightest star in the night sky.

Now draw a line through Orion’s Belt stars upward to find Aldebaran, the ruddy eye of Taurus the Bull. Aldebaran is the second star in the Circle and the brightest star in Taurus. As a matter of fact, Aldebaran is the fourteenth brightest star in the sky.

Next, continue upward in a counterclockwise direction to find the next bright star, Capella in Auriga the Charioteer. Capella is the third star on our journey and the northernmost point of the Winter Circle. In fact, Capella is the sixth brightest star in the heavens.

Completing the Circle

Then, as we start to wind down the other side of the Circle, we run into two bright stars, the twins stars in Gemini the Twins. Pollux, the brighter of the two, is our fourth corner in the Circle, and you’ll notice its “twin,” Castor, is just a bit fainter. Pollux is the sky’s 17th brightest star, and Castor is the 24th.

Our second-to-last stop around the Winter Circle is the bright star below the twins stars, Procyon. Procyon is the brightest star in Canis Minor the Lesser Dog, and in fact one of only two named stars in the constellation. For such a “minor” constellation, Procyon shines brilliantly as the seventh brightest star in the sky.

Finally, we come down to the southernmost star in the Winter Circle and the brightest of them all: Sirius in Canis Major the Greater Dog. Sirius is the brightest star in the Winter Circle and in the entire night sky. In fact, only the moon and some planets can outshine Sirius.

Finding the Winter Triangle

After you’ve found the Winter Circle, look inside it to find another asterism. That’s the Winter Triangle. First, take the last two stars of the Circle, Sirius and Procyon, then head toward the center of the Circle. That’s where you’ll find reddish star Betelgeuse, marking the shoulder of Orion. Betelgeuse makes the third corner of the Winter Triangle. Betelgeuse is the 10th brightest star in the sky and second brightest star in Orion.

Procyon, Sirius and Betelgeuse are easy to find on winter and spring evenings. Plus they form a large pattern of 3 bright stars, known as the Winter Triangle. Chart via EarthSky.

View at EarthSky Community Photos. | Cecille Kennedy of Depoe Bay, Oregon, captured this image on February 23, 2023, and wrote: “Orion appears as a beautiful giant hunter in the night sky. Orion continues to march westward and, in a few months, will disappear from the northern sky, lost in the glare of the sun. The Winter Triangle consisting of the stars Sirius, Procyon and Betelgeuse was also highly visible, as well as the Pleiades, Aldebaran of constellation Taurus and Elnath of constellation Auriga. It was a rare beautiful night for stargazing!” Thank you, Cecille!

The Circle contains areas of the Milky Way

Then for a bonus, on a dark and clear moonless night, you can see the soft-glowing river of stars that we call the Milky Way meandering right through the center of the Winter Circle.

Bottom line: The Winter Circle, aka the Winter Hexagon, is a giant shape made from some of the brightest stars in the sky, including Rigel, Aldebaran, Capella, Pollux, Procyon and Sirius. And in January 2025 Jupiter is inside the Winter Circle and Mars is nearby.

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The post Meet the Winter Circle, aka the Winter Hexagon first appeared on EarthSky.

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The Winter Circle or Winter Hexagon

The Winter Circle (or Hexagon) is a large circular pattern, made of some of the brightest stars in the Northern Hemisphere’s winter sky (or the Southern Hemisphere’s summer sky). It isn’t a constellation. It’s an asterism, or prominent group of stars that form a noticeable pattern. In addition, the Winter Circle has a smaller asterism inside it, called the Winter Triangle.

Plus in 2025 the planet Jupiter lies inside the Winter Circle and Mars is nearby.

The Winter Circle (or Winter Hexagon) isn’t a constellation. It’s an asterism, made of bright stars in the winter evening sky for the Northern Hemisphere (and summer sky for the Southern Hemisphere). It covers a large portion of the sky. Chart via EarthSky.

Meet the Winter Circle

Strictly speaking, you’ll see this circular pattern of 1st-magnitude stars – the brightest stars in our sky – from six different constellations: Rigel in Orion the Hunter, Aldebaran in Taurus the Bull, Capella in Auriga the Charioteer, Pollux (and its forever companion Castor) in Gemini the Twins, Procyon in Canis Minor the Lesser Dog and Sirius in Canis Major the Greater Dog. Also, an additional 1st-magnitude star, Betelgeuse in Orion the Hunter, lies toward the center of the Circle.

The Circle is big

The Winter Circle is big! To get an idea of the it’s humongous size, the span from the southernmost star, Sirius, to the northernmost star, Capella, covers about 1/3 of the dome of the sky.

Image of the evening sky on December 31, 2024, taken with an allsky camera. The Winter Hexagon takes up a large portion of the sky. Plus in 2025, the planets Jupiter and Mars are nearby. Image via WyoAstro observatory.

2025 lunar calendars on sale now. Makes a great gift! Check it out here.

When is the Winter Circle (or Hexagon) visible?

So, like all stars, those in the Winter Circle rise and set some four minutes earlier with each passing night. Indeed, by late January, the Winter Circle will have risen high enough above the northeastern horizon so it’s visible by about 7 p.m. local time. Then, if you look around midnight, the Winter Circle will be high above the southern horizon. And later, after about 3 a.m. local time, it sinks toward the southwestern horizon, with some of it setting in the west before sunrise.

Then, in late February and early March, the Winter Circle is in your southern sky at nightfall and early evening.

View at EarthSky Community Photos. | Jose Zarcos Palma in Mina Sao Domingo, Mertola, Portugal, took this image of the Winter Circle on December 26, 2022. Jose wrote: “I planned this composition to catch the great Winter Circle in an early stage of its ascension just behind the abandoned mining ruins of Achada do Gamo. We can clearly see Sirius in the Canis Major the Greater Dog near the chimney on the right side, just below Orion the Hunter. On top of the image, the planet Mars is near Aldebaran in Taurus the Bull.” Thank you, Jose!

Finding the Winter Circle

First, to find the Winter Circle (or Hexagon), find the easily recognizable constellation of Orion the Hunter. Indeed, its three belt stars give it away. Then, look for the bright bluish star to the lower right. This star is Rigel, the southwest corner of the Winter Circle and the first of the six stars in the Circle. By the way, Rigel is the brightest star in Orion and the seventh brightest star in the night sky.

Now draw a line through Orion’s Belt stars upward to find Aldebaran, the ruddy eye of Taurus the Bull. Aldebaran is the second star in the Circle and the brightest star in Taurus. As a matter of fact, Aldebaran is the fourteenth brightest star in the sky.

Next, continue upward in a counterclockwise direction to find the next bright star, Capella in Auriga the Charioteer. Capella is the third star on our journey and the northernmost point of the Winter Circle. In fact, Capella is the sixth brightest star in the heavens.

Completing the Circle

Then, as we start to wind down the other side of the Circle, we run into two bright stars, the twins stars in Gemini the Twins. Pollux, the brighter of the two, is our fourth corner in the Circle, and you’ll notice its “twin,” Castor, is just a bit fainter. Pollux is the sky’s 17th brightest star, and Castor is the 24th.

Our second-to-last stop around the Winter Circle is the bright star below the twins stars, Procyon. Procyon is the brightest star in Canis Minor the Lesser Dog, and in fact one of only two named stars in the constellation. For such a “minor” constellation, Procyon shines brilliantly as the seventh brightest star in the sky.

Finally, we come down to the southernmost star in the Winter Circle and the brightest of them all: Sirius in Canis Major the Greater Dog. Sirius is the brightest star in the Winter Circle and in the entire night sky. In fact, only the moon and some planets can outshine Sirius.

Finding the Winter Triangle

After you’ve found the Winter Circle, look inside it to find another asterism. That’s the Winter Triangle. First, take the last two stars of the Circle, Sirius and Procyon, then head toward the center of the Circle. That’s where you’ll find reddish star Betelgeuse, marking the shoulder of Orion. Betelgeuse makes the third corner of the Winter Triangle. Betelgeuse is the 10th brightest star in the sky and second brightest star in Orion.

Procyon, Sirius and Betelgeuse are easy to find on winter and spring evenings. Plus they form a large pattern of 3 bright stars, known as the Winter Triangle. Chart via EarthSky.

View at EarthSky Community Photos. | Cecille Kennedy of Depoe Bay, Oregon, captured this image on February 23, 2023, and wrote: “Orion appears as a beautiful giant hunter in the night sky. Orion continues to march westward and, in a few months, will disappear from the northern sky, lost in the glare of the sun. The Winter Triangle consisting of the stars Sirius, Procyon and Betelgeuse was also highly visible, as well as the Pleiades, Aldebaran of constellation Taurus and Elnath of constellation Auriga. It was a rare beautiful night for stargazing!” Thank you, Cecille!

The Circle contains areas of the Milky Way

Then for a bonus, on a dark and clear moonless night, you can see the soft-glowing river of stars that we call the Milky Way meandering right through the center of the Winter Circle.

Bottom line: The Winter Circle, aka the Winter Hexagon, is a giant shape made from some of the brightest stars in the sky, including Rigel, Aldebaran, Capella, Pollux, Procyon and Sirius. And in January 2025 Jupiter is inside the Winter Circle and Mars is nearby.

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The post Meet the Winter Circle, aka the Winter Hexagon first appeared on EarthSky.

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