A total lunar eclipse looks red. Why?

View at EarthSky Community Photos. | Patrick Prokop in Savannah, Georgia, created this composite image of the different phases of a lunar eclipse. Wonderful! Thank you, Patrick.

Read more: Total lunar eclipse of March 2-3

During a lunar eclipse, you’ll see the Earth’s shadow creeping across the moon’s face. The shadow appears dark, shaped like a bite out of a cookie, until the shadow completely covers the moon. Then, during the breathtaking time of totality, the shadow on the moon’s face appears red, rusty orange or copper-colored. Why?

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

Why a lunar eclipse looks red

The reason stems from the air we breathe. During a total lunar eclipse, the Earth lies directly between the sun and the moon. Earth casts its shadow on the moon as a result. If Earth didn’t have an atmosphere, then, when the moon is entirely within Earth’s shadow, the moon would appear black, perhaps even invisible.

However, something much more subtle and beautiful actually happens, thanks to Earth’s atmosphere.

Earth’s atmosphere extends about 50 miles (80 km) above Earth’s surface. During a total lunar eclipse, with the moon submerged in Earth’s shadow, there’s a circular ring around Earth, the ring of our atmosphere. The sun’s rays pass through this ring.

Sunlight contains a range of frequencies

White sunlight consists of a range of different colors, or frequencies. As sunlight passes through our atmosphere, the green to violet portion of the light (electromagnetic) spectrum is, essentially, filtered out. This same effect, by the way, is why our sky is blue during the day. Meanwhile, the reddish portion of the spectrum is least affected.

What’s more, when this reddish light first enters our atmosphere, it’s bent (refracted) toward the Earth’s surface. And it’s bent again when it exits on the other side of Earth. This double bending sends the reddish light onto the moon during a total lunar eclipse. It also explains why sunrises and sunsets look red.

View at EarthSky Community Photos. | Sergio Garcia Rill captured these lunar eclipse images on May 15-16, 2022, over the San Jacinto Monument in La Porte, Texas. He wrote: “I took individual images at 850mm of the phases of the moon. And later I resized them (downsized), and re-arranged and overlaid with an HDR processed image of the monument, using Photoshop.” Thank you, Sergio!

The brightness and color of a lunar eclipse

Depending on the conditions of our atmosphere at the time of the eclipse (dust, humidity, smoke, temperature and so on can all make a difference), the surviving light illuminates the moon with a color that ranges from copper-colored to deep red.

A moon in total eclipse never appears as bright as a full moon, but how dark it gets varies. The totally eclipsed moon was barely visible in December 1992, not long after the eruption of Mount Pinatubo in the Philippines, due to so much dust in Earth’s atmosphere.

View at EarthSky Community Photos. | Kathy Hunter caught these views of the lunar eclipse on March 14, 2025, from West Virginia. Kathy wrote: “My first composite!” Thank you, Kathy.

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, wrote: “The forecast was rainy, and the clouds were thick. We didn’t see the moonrise. Hours later, there was a clearing on the other side and a few stars became visible. I went outside to see the most beautiful blood red moon playing hide and seek with the clouds. I managed to take a few shots before dark clouds covered the night, and the rains came.” Thank you, Cecille!

All total lunar eclipses do not look alike

Can anyone know in advance how red or dark the moon will appear during a total lunar eclipse? Not really. Before an eclipse takes place, you’ll hear people speculate about it. That uncertainty is part of the fun of eclipses, so enjoy! And watch for the red moon during a lunar eclipse.

View at EarthSky Community Photos. | Petr Horálek captured these full moons from the Cerro Tololo Observatory in Chile. Petr wrote: “I made it happen (with no sleep yet) to finalize today’s lunar eclipse triplet, as the eclipse was truly beautiful over the CTIO Cerro Tololo observatory, Chile. Colors in the Earth’s shadow were vivid, including the turquoise effect at the start and even end of the eclipse (where primarily the ozone layer causes a bluish tint, referring to Richard Keen’s explanation from 2007). The effect was easily capturable on camera, but also nicely visible to binoculars.” Amazing, thank you! Image via Petr Horálek/ CTIO (Cerro Tololo Observatory)/ AURA/ NFS/ NOIRLab.

What about that blue band?

Another color to watch for at the beginning and end of totality is a blue band of light along the limb (edge) of the moon. This blue band is light passing through our ozone layer – which absorbs red light – that allows blue light to come through. The blue band is frequently caught in photos but may be hard to see visually.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Bottom line: Coming up … the total lunar eclipse of March 2-3, 2026. At maximum eclipse, the moon will look red. But why? Earth’s atmosphere is the key.

March 13-14, 2025, total lunar eclipse: Astonishing images via EarthSky’s community

Post your eclipse photo to EarthSky Community Photos

The post A total lunar eclipse looks red. Why? first appeared on EarthSky.

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View at EarthSky Community Photos. | Patrick Prokop in Savannah, Georgia, created this composite image of the different phases of a lunar eclipse. Wonderful! Thank you, Patrick.

Read more: Total lunar eclipse of March 2-3

During a lunar eclipse, you’ll see the Earth’s shadow creeping across the moon’s face. The shadow appears dark, shaped like a bite out of a cookie, until the shadow completely covers the moon. Then, during the breathtaking time of totality, the shadow on the moon’s face appears red, rusty orange or copper-colored. Why?

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

Why a lunar eclipse looks red

The reason stems from the air we breathe. During a total lunar eclipse, the Earth lies directly between the sun and the moon. Earth casts its shadow on the moon as a result. If Earth didn’t have an atmosphere, then, when the moon is entirely within Earth’s shadow, the moon would appear black, perhaps even invisible.

However, something much more subtle and beautiful actually happens, thanks to Earth’s atmosphere.

Earth’s atmosphere extends about 50 miles (80 km) above Earth’s surface. During a total lunar eclipse, with the moon submerged in Earth’s shadow, there’s a circular ring around Earth, the ring of our atmosphere. The sun’s rays pass through this ring.

Sunlight contains a range of frequencies

White sunlight consists of a range of different colors, or frequencies. As sunlight passes through our atmosphere, the green to violet portion of the light (electromagnetic) spectrum is, essentially, filtered out. This same effect, by the way, is why our sky is blue during the day. Meanwhile, the reddish portion of the spectrum is least affected.

What’s more, when this reddish light first enters our atmosphere, it’s bent (refracted) toward the Earth’s surface. And it’s bent again when it exits on the other side of Earth. This double bending sends the reddish light onto the moon during a total lunar eclipse. It also explains why sunrises and sunsets look red.

View at EarthSky Community Photos. | Sergio Garcia Rill captured these lunar eclipse images on May 15-16, 2022, over the San Jacinto Monument in La Porte, Texas. He wrote: “I took individual images at 850mm of the phases of the moon. And later I resized them (downsized), and re-arranged and overlaid with an HDR processed image of the monument, using Photoshop.” Thank you, Sergio!

The brightness and color of a lunar eclipse

Depending on the conditions of our atmosphere at the time of the eclipse (dust, humidity, smoke, temperature and so on can all make a difference), the surviving light illuminates the moon with a color that ranges from copper-colored to deep red.

A moon in total eclipse never appears as bright as a full moon, but how dark it gets varies. The totally eclipsed moon was barely visible in December 1992, not long after the eruption of Mount Pinatubo in the Philippines, due to so much dust in Earth’s atmosphere.

View at EarthSky Community Photos. | Kathy Hunter caught these views of the lunar eclipse on March 14, 2025, from West Virginia. Kathy wrote: “My first composite!” Thank you, Kathy.

View at EarthSky Community Photos. | Cecille Kennedy in Depoe Bay, Oregon, wrote: “The forecast was rainy, and the clouds were thick. We didn’t see the moonrise. Hours later, there was a clearing on the other side and a few stars became visible. I went outside to see the most beautiful blood red moon playing hide and seek with the clouds. I managed to take a few shots before dark clouds covered the night, and the rains came.” Thank you, Cecille!

All total lunar eclipses do not look alike

Can anyone know in advance how red or dark the moon will appear during a total lunar eclipse? Not really. Before an eclipse takes place, you’ll hear people speculate about it. That uncertainty is part of the fun of eclipses, so enjoy! And watch for the red moon during a lunar eclipse.

View at EarthSky Community Photos. | Petr Horálek captured these full moons from the Cerro Tololo Observatory in Chile. Petr wrote: “I made it happen (with no sleep yet) to finalize today’s lunar eclipse triplet, as the eclipse was truly beautiful over the CTIO Cerro Tololo observatory, Chile. Colors in the Earth’s shadow were vivid, including the turquoise effect at the start and even end of the eclipse (where primarily the ozone layer causes a bluish tint, referring to Richard Keen’s explanation from 2007). The effect was easily capturable on camera, but also nicely visible to binoculars.” Amazing, thank you! Image via Petr Horálek/ CTIO (Cerro Tololo Observatory)/ AURA/ NFS/ NOIRLab.

What about that blue band?

Another color to watch for at the beginning and end of totality is a blue band of light along the limb (edge) of the moon. This blue band is light passing through our ozone layer – which absorbs red light – that allows blue light to come through. The blue band is frequently caught in photos but may be hard to see visually.

In a lunar eclipse, the sun, Earth and moon line up, with the Earth in the middle. Image via NASA.

Bottom line: Coming up … the total lunar eclipse of March 2-3, 2026. At maximum eclipse, the moon will look red. But why? Earth’s atmosphere is the key.

March 13-14, 2025, total lunar eclipse: Astonishing images via EarthSky’s community

Post your eclipse photo to EarthSky Community Photos

The post A total lunar eclipse looks red. Why? first appeared on EarthSky.

from EarthSky https://ift.tt/xX9QFT5

When’s the first day of spring? All you need to know

View at EarthSky Community Photos. | EarthSky’s own Claudia Crowley snapped this daffodil in her front yard in Fort Worth, Texas, on February 19, 2026. Claudia wrote: “They’ve come up! It’s spring here. We left the leaves over the winter as habitat for hibernating insects.” Thank you, Claudia. When’s the first day of spring? That depends on if you ask an astronomer or a meteorologist, because you’ll get 2 different answers! We explain the difference, below.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

When’s the first day of spring?

If you ask a Northern Hemisphere astronomer when the first day of spring will be this year, they’ll likely say spring arrives at 14:46 UTC (9:46 a.m. CDT) on March 20, 2026. But a meteorologist or climatologist would give you a different answer. They’d likely say spring starts on March 1.

Are there two different spring seasons? Read on to find out why astronomical spring and meteorological spring start at different times.

Astronomical spring

Earth has a 23.5-degree tilt as it orbits the sun. This tilt toward or away from the sun determines the seasons we feel across the globe. The spring (or vernal) equinox occurs when the sun passes over the equator from south to north and marks the start of warmer months across the Northern Hemisphere.

Because astronomical spring is tied to the rotation of Earth and the exact moment the sun crosses the equator, the first day of the spring season can shift by a day from year to year. This also means the length of the spring season can vary. Likewise, the autumnal equinox, or start of fall, can also have different start dates.

Meteorological spring

Meteorological spring starts on March 1 and runs through May 31 every year, regardless of the exact moment of the vernal equinox. This allows the seasons to be more consistent, which is important when looking at weather data, especially temperatures. With more consistent seasons, meteorologists and climatologists are able to better analyze temperature trends and precipitation patterns across a set period of time. Calculating a seasonal average is much easier when that season starts and ends on the same day year after year.

Comparing astronomical seasons with meteorological seasons. Image via NOAA.

Image via Pexels.

Spring weather

Spring is a transition season in the Northern Hemisphere. It’s as simple as it sounds. During the spring season we are transitioning out of the colder winter months into the warmer months of spring and eventually summer. This also means our weather tends to be more active. The dramatic changes from cold to warm can create chaos, with severe weather outbreaks and late-season snowstorms. Plus, frosts and freezes well into the spring growing season can have an impact on sensitive crops.

As temperatures start to warm across North America, colder air from the Arctic can still spill down with dips in the jet stream. (The jet stream is the band of strong winds in the upper levels of the atmosphere that separates the warm and cold air.) This class of colder air colliding with warm, moist air can create an environment in which severe storms can develop.

Severe storms (and those capable of producing tornadoes) can happen in any season. But they’re most common in the spring and summer months as temperatures warm. Severe storms that produce tornadoes are more common in spring across the Gulf Coast. But across the plains of the United States, the typical tornado season is from late spring into early summer.

An Oklahoma thunderstorm. Image via Branden Stephenson/ Pexels.

First day of spring is a reminder of thunderstorm and tornado safety

Early spring is a great time to remember severe weather safety! Only 10% of all thunderstorms in the United States go on to become severe. A severe thunderstorm is defined as one with winds of more than 58 miles per hour (93 kph) and/or hail 1 inch (2.5 cm) or greater in diameter. But all thunderstorms are dangerous due to the presence of lightning. If you can hear thunder, the storm is close enough for you to be struck by lightning. As soon as a storm is nearby, go inside a building or vehicle to wait out the storm, and wait at least 30 minutes from the last lightning strike to resume any outdoor activities.

Image via NOAA/ National Weather Service.

In the event of a tornado, time is vital. As soon as a tornado warning is issued, go to the lowest level and most central part of your home or building. An interior closet or bathroom away from outside walls and windows is best.

If you live in a mobile home, you need to get out and find another place to shelter. The strong winds of a tornado can pick mobile homes up off the ground. If there is a risk of tornadoes and you live in a mobile home, contact a trusted neighbor or family member who has a basement or shelter of some kind that you can stay in until the threat of tornadoes has passed.

It’s the same for those out on the road: You are not safe in a car during a tornado. Get off the road and find a business or shelter to wait out the tornado.

Where to shelter in a house. Image via NOAA/ National Weather Service.

Spring outlook 2026

So what will this spring bring us? In general: a good portion of the country will have higher chances of above-normal temperatures. As for precipitation, the Great Lakes will have higher chances of being wetter than normal, while the southwest will have a lower chance of precipitation.

Image via NOAA/ Climate Prediction Center.

Image via NOAA/ Climate Prediction Center.

Bottom line: While astronomical spring doesn’t start until March 20, meteorologists and climatologists use March 1 as the start of spring for consistency.

Via NOAA

The post When’s the first day of spring? All you need to know first appeared on EarthSky.

from EarthSky https://ift.tt/qZRoUVD

View at EarthSky Community Photos. | EarthSky’s own Claudia Crowley snapped this daffodil in her front yard in Fort Worth, Texas, on February 19, 2026. Claudia wrote: “They’ve come up! It’s spring here. We left the leaves over the winter as habitat for hibernating insects.” Thank you, Claudia. When’s the first day of spring? That depends on if you ask an astronomer or a meteorologist, because you’ll get 2 different answers! We explain the difference, below.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

When’s the first day of spring?

If you ask a Northern Hemisphere astronomer when the first day of spring will be this year, they’ll likely say spring arrives at 14:46 UTC (9:46 a.m. CDT) on March 20, 2026. But a meteorologist or climatologist would give you a different answer. They’d likely say spring starts on March 1.

Are there two different spring seasons? Read on to find out why astronomical spring and meteorological spring start at different times.

Astronomical spring

Earth has a 23.5-degree tilt as it orbits the sun. This tilt toward or away from the sun determines the seasons we feel across the globe. The spring (or vernal) equinox occurs when the sun passes over the equator from south to north and marks the start of warmer months across the Northern Hemisphere.

Because astronomical spring is tied to the rotation of Earth and the exact moment the sun crosses the equator, the first day of the spring season can shift by a day from year to year. This also means the length of the spring season can vary. Likewise, the autumnal equinox, or start of fall, can also have different start dates.

Meteorological spring

Meteorological spring starts on March 1 and runs through May 31 every year, regardless of the exact moment of the vernal equinox. This allows the seasons to be more consistent, which is important when looking at weather data, especially temperatures. With more consistent seasons, meteorologists and climatologists are able to better analyze temperature trends and precipitation patterns across a set period of time. Calculating a seasonal average is much easier when that season starts and ends on the same day year after year.

Comparing astronomical seasons with meteorological seasons. Image via NOAA.

Image via Pexels.

Spring weather

Spring is a transition season in the Northern Hemisphere. It’s as simple as it sounds. During the spring season we are transitioning out of the colder winter months into the warmer months of spring and eventually summer. This also means our weather tends to be more active. The dramatic changes from cold to warm can create chaos, with severe weather outbreaks and late-season snowstorms. Plus, frosts and freezes well into the spring growing season can have an impact on sensitive crops.

As temperatures start to warm across North America, colder air from the Arctic can still spill down with dips in the jet stream. (The jet stream is the band of strong winds in the upper levels of the atmosphere that separates the warm and cold air.) This class of colder air colliding with warm, moist air can create an environment in which severe storms can develop.

Severe storms (and those capable of producing tornadoes) can happen in any season. But they’re most common in the spring and summer months as temperatures warm. Severe storms that produce tornadoes are more common in spring across the Gulf Coast. But across the plains of the United States, the typical tornado season is from late spring into early summer.

An Oklahoma thunderstorm. Image via Branden Stephenson/ Pexels.

First day of spring is a reminder of thunderstorm and tornado safety

Early spring is a great time to remember severe weather safety! Only 10% of all thunderstorms in the United States go on to become severe. A severe thunderstorm is defined as one with winds of more than 58 miles per hour (93 kph) and/or hail 1 inch (2.5 cm) or greater in diameter. But all thunderstorms are dangerous due to the presence of lightning. If you can hear thunder, the storm is close enough for you to be struck by lightning. As soon as a storm is nearby, go inside a building or vehicle to wait out the storm, and wait at least 30 minutes from the last lightning strike to resume any outdoor activities.

Image via NOAA/ National Weather Service.

In the event of a tornado, time is vital. As soon as a tornado warning is issued, go to the lowest level and most central part of your home or building. An interior closet or bathroom away from outside walls and windows is best.

If you live in a mobile home, you need to get out and find another place to shelter. The strong winds of a tornado can pick mobile homes up off the ground. If there is a risk of tornadoes and you live in a mobile home, contact a trusted neighbor or family member who has a basement or shelter of some kind that you can stay in until the threat of tornadoes has passed.

It’s the same for those out on the road: You are not safe in a car during a tornado. Get off the road and find a business or shelter to wait out the tornado.

Where to shelter in a house. Image via NOAA/ National Weather Service.

Spring outlook 2026

So what will this spring bring us? In general: a good portion of the country will have higher chances of above-normal temperatures. As for precipitation, the Great Lakes will have higher chances of being wetter than normal, while the southwest will have a lower chance of precipitation.

Image via NOAA/ Climate Prediction Center.

Image via NOAA/ Climate Prediction Center.

Bottom line: While astronomical spring doesn’t start until March 20, meteorologists and climatologists use March 1 as the start of spring for consistency.

Via NOAA

The post When’s the first day of spring? All you need to know first appeared on EarthSky.

from EarthSky https://ift.tt/qZRoUVD

March birthstone: Beautiful cool blue or blood red?

Natural aquamarine crystals. Aquamarine is a March birthstone. Image via Gunnar Ries Amphibol/ Wikimedia Commons (CC BY-SA 2.5).

For a March birthstone you can take your choice, aquamarine or bloodstone.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

March birthstone 1: aquamarine

Aquamarine – also called the “poor man’s diamond” – is a form of the mineral beryl that also includes other gemstones such as the emerald, morganite, and heliodor. Beryl consists of four elements: beryllium, aluminum, silicon, and oxygen. Beryl occurs as free six-sided crystals in rock veins, and is a relatively hard gem, ranking after the diamond, sapphire, ruby, alexandrite, and topaz.

Aquamarines vary in color from deep blue to blue-green of different intensities. Traces of iron in the beryl crystal cause these color variations. Naturally occurring deep blue stones are the most prized – and most expensive – because they are rare. However, you can heat yellow beryl stones to change them to blue aquamarines.

The best commercial source of aquamarines is Brazil. Also, you can find high quality stones in Colombia, the Ural Mountains of Russia, the island of Malagasy, and India. In the United States, Colorado, Maine, and North Carolina are the best sources.

An aquamarine gemstone. Image via Gem Rock auctions. Used with permission.

Aquamarine lore

The Romans derived the name aquamarine from the words “aqua,” meaning water, and “mare,” meaning sea, because it looked like sea water. Aquamarines were believed to have originated from the jewel caskets of sirens, washed ashore from the depths of the sea. They were considered sacred to Neptune, Roman god of the sea. This association with the sea made it the sailors’ gem, promising prosperous and safe voyages, as well as protection against perils and monsters of the sea. The Greeks first documented its use between 480-300 BCE. They wore aquamarine amulets engraved with Poseidon (the Greek god of the sea) on a chariot.

Supposedly Emperor Nero used aquamarine as an eyeglass 2,000 years ago. Much later, aquamarines were used as glasses in Germany to correct shortsightedness. In fact, the German name for eyeglasses today is “brille,” derived from the word for beryl.

Romans believed aquamarines possessed medicinal and healing powers, curing ailments of the stomach, liver, jaws, and throat. During the Middle Ages, the aquamarine supposedly acted as an antidote against poison. Soothsayers, who called it the “magic mirror,” used it for telling fortunes and answering questions about the future.

March birthstone 2: bloodstone

Rough bloodstone, also known as heliotrope, a form of chalcedony. Image via James St. John/ Wikimedia Commons (CC BY 2.0).

The second birthstone for March is the bloodstone. Bloodstone – also known as heliotrope – is a form of the abundant mineral quartz. This particular form of quartz, known as cryptocrystalline quartz, exists as a mass of tiny quartz crystals formed together in large lumps that show no external crystal form, yet each of the component crystals that make up the mass is a genuine crystal. This quartz variety is also called chalcedony. Green chalcedony spotted with flecks of red is known as bloodstone. Bloodstone is found embedded in rocks or as pebbles in riverbeds. The best sources of this stone are India, Brazil, and Australia.

Bloodstone. Image via Ra’ike/ Wikimedia Commons (CC BY-SA 3.0).

Bloodstone lore

The bloodstone is a favored material for carving religious subjects. The Italian Matteo del Nassaro made a particularly famous carving around 1525. In “The Descent from the Cross,” the sculptor carefully crafted the piece so that spots of red on the bloodstone represented the wounds of Christ and his drops of blood. According to legend, bloodstone formed during the crucifixion of Christ. A Roman soldier-guard thrust his spear into Christ’s side and drops of blood fell on some pieces of dark green jasper lying at the foot of the cross, and the bloodstone was created.

Babylonians used this stone to make seals and amulets, and it was also a favorite with Roman gladiators. In the Middle Ages, bloodstone was believed to hold healing powers, particularly for stopping nosebleeds. Powdered and mixed with honey and white of egg, it was believed to cure tumors and stop all types of hemorrhage. Ancient alchemists used it to treat blood disorders, including blood poisoning and the flow of blood from a wound. Bloodstone was also believed to draw out the venom of snakes.

Find out about the birthstones for the other months of the year.

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

Bottom line: March babies have two birthstones to choose from as their birthstone. There’s the blue aquamarine or the red-speckled bloodstone.

The post March birthstone: Beautiful cool blue or blood red? first appeared on EarthSky.

from EarthSky https://ift.tt/aVbseJz

Natural aquamarine crystals. Aquamarine is a March birthstone. Image via Gunnar Ries Amphibol/ Wikimedia Commons (CC BY-SA 2.5).

For a March birthstone you can take your choice, aquamarine or bloodstone.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

March birthstone 1: aquamarine

Aquamarine – also called the “poor man’s diamond” – is a form of the mineral beryl that also includes other gemstones such as the emerald, morganite, and heliodor. Beryl consists of four elements: beryllium, aluminum, silicon, and oxygen. Beryl occurs as free six-sided crystals in rock veins, and is a relatively hard gem, ranking after the diamond, sapphire, ruby, alexandrite, and topaz.

Aquamarines vary in color from deep blue to blue-green of different intensities. Traces of iron in the beryl crystal cause these color variations. Naturally occurring deep blue stones are the most prized – and most expensive – because they are rare. However, you can heat yellow beryl stones to change them to blue aquamarines.

The best commercial source of aquamarines is Brazil. Also, you can find high quality stones in Colombia, the Ural Mountains of Russia, the island of Malagasy, and India. In the United States, Colorado, Maine, and North Carolina are the best sources.

An aquamarine gemstone. Image via Gem Rock auctions. Used with permission.

Aquamarine lore

The Romans derived the name aquamarine from the words “aqua,” meaning water, and “mare,” meaning sea, because it looked like sea water. Aquamarines were believed to have originated from the jewel caskets of sirens, washed ashore from the depths of the sea. They were considered sacred to Neptune, Roman god of the sea. This association with the sea made it the sailors’ gem, promising prosperous and safe voyages, as well as protection against perils and monsters of the sea. The Greeks first documented its use between 480-300 BCE. They wore aquamarine amulets engraved with Poseidon (the Greek god of the sea) on a chariot.

Supposedly Emperor Nero used aquamarine as an eyeglass 2,000 years ago. Much later, aquamarines were used as glasses in Germany to correct shortsightedness. In fact, the German name for eyeglasses today is “brille,” derived from the word for beryl.

Romans believed aquamarines possessed medicinal and healing powers, curing ailments of the stomach, liver, jaws, and throat. During the Middle Ages, the aquamarine supposedly acted as an antidote against poison. Soothsayers, who called it the “magic mirror,” used it for telling fortunes and answering questions about the future.

March birthstone 2: bloodstone

Rough bloodstone, also known as heliotrope, a form of chalcedony. Image via James St. John/ Wikimedia Commons (CC BY 2.0).

The second birthstone for March is the bloodstone. Bloodstone – also known as heliotrope – is a form of the abundant mineral quartz. This particular form of quartz, known as cryptocrystalline quartz, exists as a mass of tiny quartz crystals formed together in large lumps that show no external crystal form, yet each of the component crystals that make up the mass is a genuine crystal. This quartz variety is also called chalcedony. Green chalcedony spotted with flecks of red is known as bloodstone. Bloodstone is found embedded in rocks or as pebbles in riverbeds. The best sources of this stone are India, Brazil, and Australia.

Bloodstone. Image via Ra’ike/ Wikimedia Commons (CC BY-SA 3.0).

Bloodstone lore

The bloodstone is a favored material for carving religious subjects. The Italian Matteo del Nassaro made a particularly famous carving around 1525. In “The Descent from the Cross,” the sculptor carefully crafted the piece so that spots of red on the bloodstone represented the wounds of Christ and his drops of blood. According to legend, bloodstone formed during the crucifixion of Christ. A Roman soldier-guard thrust his spear into Christ’s side and drops of blood fell on some pieces of dark green jasper lying at the foot of the cross, and the bloodstone was created.

Babylonians used this stone to make seals and amulets, and it was also a favorite with Roman gladiators. In the Middle Ages, bloodstone was believed to hold healing powers, particularly for stopping nosebleeds. Powdered and mixed with honey and white of egg, it was believed to cure tumors and stop all types of hemorrhage. Ancient alchemists used it to treat blood disorders, including blood poisoning and the flow of blood from a wound. Bloodstone was also believed to draw out the venom of snakes.

Find out about the birthstones for the other months of the year.

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

Bottom line: March babies have two birthstones to choose from as their birthstone. There’s the blue aquamarine or the red-speckled bloodstone.

The post March birthstone: Beautiful cool blue or blood red? first appeared on EarthSky.

from EarthSky https://ift.tt/aVbseJz

Leap years, and why 2026 isn’t one

This video shows why we have leap years. And it shows what happens if we don’t..

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Why 2026 isn’t a leap year

The last leap year was 2024. So 2028 will be our next leap year, a 366-day-long year, with an extra day added to our calendar (February 29). We’ll call that extra day a leap day. It’ll help synchronize our human-created calendars with Earth’s orbit around the sun and with the passing of the seasons. Why do we need the extra day? Blame Earth’s orbit. Our planet takes approximately 365.25 days to orbit the sun once. It’s that .25 that creates the need for a leap year every four years.

During non-leap years, aka common years – like 2026 – the calendar doesn’t take into account the extra quarter of a day required by Earth to complete a single orbit. In essence, the calendar year, which is a human artifact, is faster than the solar year, the 365 days 5 hours 48 minutes 46 seconds that our planet requires to orbit the sun once.

Over time and without correction, the calendar year would drift away from the solar year. And the drift would add up quickly. For example, without correction the calendar year would be off by about one day after four years. It’d be off by about 25 days after 100 years. You can see that, if even more time were to pass without the leap year as a calendar correction, eventually February would be a summer month in the Northern Hemisphere.

Christopher Clavius (1538-1612). This German mathematician and astronomer figured out how and where to place leap years in the Gregorian calendar. Image via Wikipedia.

Leap years and the Gregorian calendar

Leap days were first added to the Julian Calendar in 46 BCE by Julius Caesar at the advice of Sosigenes, an Alexandrian astronomer.

In 1582, Pope Gregory XIII revised the Julian calendar by creating the Gregorian calendar with the assistance of Christopher Clavius, a German mathematician and astronomer. The Gregorian calendar stated that leap days should not be added in years ending in “00” unless that year is also divisible by 400. This additional correction was added to stabilize the calendar over a period of thousands of years and was necessary because solar years are actually slightly less than 365.25 days. In fact, a solar year occurs over a period of 365.2422 days.

When are leap years?

So, according to the rules set forth in the Gregorian calendar, leap years have occurred or will occur during the following years:

1600 1604 1608 1612 1616 1620 1624 1628 1632 1636 1640 1644 1648 1652 1656 1660 1664 1668 1672 1676 1680 1684 1688 1692 1696 1704 1708 1712 1716 1720 1724 1728 1732 1736 1740 1744 1748 1752 1756 1760 1764 1768 1772 1776 1780 1784 1788 1792 1796 1804 1808 1812 1816 1820 1824 1828 1832 1836 1840 1844 1848 1852 1856 1860 1864 1868 1872 1876 1880 1884 1888 1892 1896 1904 1908 1912 1916 1920 1924 1928 1932 1936 1940 1944 1948 1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064 2068 2072 2076 2080 2084 2088 2092 2096 2104 2108 2112 2116 2120 2124 2128 2132 2136 2140 2144 2148 2152.

Notice that 2000 was a leap year because it is divisible by 400, but that 1900 was not a leap year.

Since 1582, the Gregorian calendar has been gradually adopted as a “civil” international standard for many countries around the world.

Leap year lore

In medieval Ireland and Scotland, women were allowed to propose marriage to men on February 29 of any leap year. A man who rejected the proposal owed a fine to the woman.

Children born on Leap Day have a true birthday every four years. They generally will celebrate their birth on February 28 or March 1.

Some cultures consider a leap year unlucky – for people or animals – all year long.

A view of the sun above the limb of the Earth, from Earth orbit. Image via NASA.

Bottom line: 2026 isn’t a leap year. But 2028 will be. Why do we have leap years?

The post Leap years, and why 2026 isn’t one first appeared on EarthSky.

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This video shows why we have leap years. And it shows what happens if we don’t..

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Why 2026 isn’t a leap year

The last leap year was 2024. So 2028 will be our next leap year, a 366-day-long year, with an extra day added to our calendar (February 29). We’ll call that extra day a leap day. It’ll help synchronize our human-created calendars with Earth’s orbit around the sun and with the passing of the seasons. Why do we need the extra day? Blame Earth’s orbit. Our planet takes approximately 365.25 days to orbit the sun once. It’s that .25 that creates the need for a leap year every four years.

During non-leap years, aka common years – like 2026 – the calendar doesn’t take into account the extra quarter of a day required by Earth to complete a single orbit. In essence, the calendar year, which is a human artifact, is faster than the solar year, the 365 days 5 hours 48 minutes 46 seconds that our planet requires to orbit the sun once.

Over time and without correction, the calendar year would drift away from the solar year. And the drift would add up quickly. For example, without correction the calendar year would be off by about one day after four years. It’d be off by about 25 days after 100 years. You can see that, if even more time were to pass without the leap year as a calendar correction, eventually February would be a summer month in the Northern Hemisphere.

Christopher Clavius (1538-1612). This German mathematician and astronomer figured out how and where to place leap years in the Gregorian calendar. Image via Wikipedia.

Leap years and the Gregorian calendar

Leap days were first added to the Julian Calendar in 46 BCE by Julius Caesar at the advice of Sosigenes, an Alexandrian astronomer.

In 1582, Pope Gregory XIII revised the Julian calendar by creating the Gregorian calendar with the assistance of Christopher Clavius, a German mathematician and astronomer. The Gregorian calendar stated that leap days should not be added in years ending in “00” unless that year is also divisible by 400. This additional correction was added to stabilize the calendar over a period of thousands of years and was necessary because solar years are actually slightly less than 365.25 days. In fact, a solar year occurs over a period of 365.2422 days.

When are leap years?

So, according to the rules set forth in the Gregorian calendar, leap years have occurred or will occur during the following years:

1600 1604 1608 1612 1616 1620 1624 1628 1632 1636 1640 1644 1648 1652 1656 1660 1664 1668 1672 1676 1680 1684 1688 1692 1696 1704 1708 1712 1716 1720 1724 1728 1732 1736 1740 1744 1748 1752 1756 1760 1764 1768 1772 1776 1780 1784 1788 1792 1796 1804 1808 1812 1816 1820 1824 1828 1832 1836 1840 1844 1848 1852 1856 1860 1864 1868 1872 1876 1880 1884 1888 1892 1896 1904 1908 1912 1916 1920 1924 1928 1932 1936 1940 1944 1948 1952 1956 1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012 2016 2020 2024 2028 2032 2036 2040 2044 2048 2052 2056 2060 2064 2068 2072 2076 2080 2084 2088 2092 2096 2104 2108 2112 2116 2120 2124 2128 2132 2136 2140 2144 2148 2152.

Notice that 2000 was a leap year because it is divisible by 400, but that 1900 was not a leap year.

Since 1582, the Gregorian calendar has been gradually adopted as a “civil” international standard for many countries around the world.

Leap year lore

In medieval Ireland and Scotland, women were allowed to propose marriage to men on February 29 of any leap year. A man who rejected the proposal owed a fine to the woman.

Children born on Leap Day have a true birthday every four years. They generally will celebrate their birth on February 28 or March 1.

Some cultures consider a leap year unlucky – for people or animals – all year long.

A view of the sun above the limb of the Earth, from Earth orbit. Image via NASA.

Bottom line: 2026 isn’t a leap year. But 2028 will be. Why do we have leap years?

The post Leap years, and why 2026 isn’t one first appeared on EarthSky.

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Giant ‘spiderwebs’ on Mars reveal surprising water clues

View larger. | NASA’s Curiosity rover captured this closeup view of some of the red planet’s boxwork – or “spiderweb” – formations on September 26, 2025. These “spiderwebs” on Mars are evidence for ancient groundwater in Gale Crater. Surprisingly, that groundwater table was higher in elevation and lasted longer than scientists thought. Image via NASA/ JPL-Caltech/ MSSS.

• Mars has giant “spiderwebs” on Mount Sharp in Gale Crater. They are a network of geologic ridges and hollows that extend for miles.
• NASA’s Curiosity rover has been exploring these ridges – also called boxwork – for the past six months.
• Ancient groundwater seeping through large cracks formed the intriguing formations, according to scientists.

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

A close look at ‘spiderwebs’ on Mars

NASA’s Curiosity rover has been taking a close look at some spiderwebs on Mars. Not webs made by actual Martian spiders, of course, but sprawling geologic formations that resemble spiderwebs when seen from above. The grid-like formations – called boxwork – consist of ridges about 3 to 6 feet (1 to 2 meters) tall with sandy hollows in between them. They extend for miles in the region of Mount Sharp in Gale Crater. NASA scientists said on February 23, 2026, that ancient groundwater likely formed the intriguing features. Their location on the mountain also suggests that the ancient groundwater table was higher in elevation and longer-lived than previously thought.

The groundwater would have flowed through fractures in the bedrock. In doing so, the water left behind mineral deposits. Later, the areas with the minerals hardened into ridges, while the wind gradually eroded away softer rock, leaving behind the standing ridges. Now we still see the vast network of ridges and hollows, even though the water has long disappeared.

Curiosity has been exploring the spiderweb region for about the past six months.

View larger. | NASA’s Mars Reconnaissance Orbiter captured this image of a network of spiderweb-like ridges – called boxwork by scientists – on Mount Sharp in Gale Crater on Mars on December 10, 2006. Image via NASA/ JPL-Caltech/ University of Arizona.

Maneuvering through the ridges

For the rover, maneuvering through the boxwork ridges can be a bit tricky. The rover can roll across the tops of the ridges, but they are not much wider than the rover itself. Also, Curiosity can move down into the sandy areas between the ridges, but it has to be careful not to get stuck. Operations systems engineer Ashley Stroupe at NASA’s Jet Propulsion Laboratory in Southern California is the Curiosity Rover Planner (Drive) team lead. She said:

It almost feels like a highway we can drive on. But then we have to go down into the hollows, where you need to be mindful of Curiosity’s wheels slipping or having trouble turning in the sand. There’s always a solution. It just takes trying different paths.

Operations systems engineer Ashley Stroupe at NASA’s Jet Propulsion Laboratory is the Curiosity Rover Planner (Drive) team lead. Image via NASA.

How did the boxwork ridges form?

The boxwork ridges are located on the slopes of Mount Sharp, which sits in the middle of Gale Crater and is about 3 miles (5 kilometers) tall. So, how did they form there? Similar formations exist on Earth, in fact, but they are usually only a few centimeters tall at most and found in caves or dry, sandy environments.

The higher elevations of Mount Sharp record a drier period in the history of Gale Crater, which was once a lake billions of years ago. The boxwork formations are surprisingly high up the mountain, however. Mission scientist Tina Seeger at Rice University in Houston, Texas, explained:

Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high. And that means the water needed for sustaining life could have lasted much longer than we thought looking from orbit.

In addition, orbiting spacecraft have also imaged the boxwork from high above. Intriguingly, the images showed dark lines going across the spiderwebs. Scientists said they were likely central fractures. That’s where the groundwater would have seeped up to the surface. Now, seeing them up close, Curiosity has confirmed they are indeed fractures.

Nodules in the spiderwebs

Additionally, Curiosity has also found other evidence for past groundwater in this region. For example, some of the rocks have bumpy textures comprised of small nodules. But there is another mystery to be solved, too. The nodules aren’t where scientists expected them to be, near the fractures. Instead, they’re along the walls of the ridges and on rocks in the sandy hollows. Seeger said:

We can’t quite explain yet why the nodules appear where they do. Maybe the ridges were cemented by minerals first, and later episodes of groundwater left nodules around them.

While the spiderwebs themselves have nothing to do with Martian life, they do provide new clues about water and habitable conditions in Mars’ past. What other discoveries might be hiding in the webs, waiting to be found?

View larger. | Closeup view of pea-sized nodules in the boxwork (spiderweb) formations. Groundwater formed them billions of years ago. Image via NASA/ JPL-Caltech/ MSSS.

Bottom line: NASA’s Curiosity rover has been investigating “spiderwebs” on Mars. Groundwater formed these grid-like formations of ridges billions of years ago.

Via NASA

Read more: Mars rover Curiosity heads for intriguing ‘spiderwebs’

Read more: Martian rock crushed by Curiosity hides a surprise!

The post Giant ‘spiderwebs’ on Mars reveal surprising water clues first appeared on EarthSky.

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View larger. | NASA’s Curiosity rover captured this closeup view of some of the red planet’s boxwork – or “spiderweb” – formations on September 26, 2025. These “spiderwebs” on Mars are evidence for ancient groundwater in Gale Crater. Surprisingly, that groundwater table was higher in elevation and lasted longer than scientists thought. Image via NASA/ JPL-Caltech/ MSSS.

• Mars has giant “spiderwebs” on Mount Sharp in Gale Crater. They are a network of geologic ridges and hollows that extend for miles.
• NASA’s Curiosity rover has been exploring these ridges – also called boxwork – for the past six months.
• Ancient groundwater seeping through large cracks formed the intriguing formations, according to scientists.

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

A close look at ‘spiderwebs’ on Mars

NASA’s Curiosity rover has been taking a close look at some spiderwebs on Mars. Not webs made by actual Martian spiders, of course, but sprawling geologic formations that resemble spiderwebs when seen from above. The grid-like formations – called boxwork – consist of ridges about 3 to 6 feet (1 to 2 meters) tall with sandy hollows in between them. They extend for miles in the region of Mount Sharp in Gale Crater. NASA scientists said on February 23, 2026, that ancient groundwater likely formed the intriguing features. Their location on the mountain also suggests that the ancient groundwater table was higher in elevation and longer-lived than previously thought.

The groundwater would have flowed through fractures in the bedrock. In doing so, the water left behind mineral deposits. Later, the areas with the minerals hardened into ridges, while the wind gradually eroded away softer rock, leaving behind the standing ridges. Now we still see the vast network of ridges and hollows, even though the water has long disappeared.

Curiosity has been exploring the spiderweb region for about the past six months.

View larger. | NASA’s Mars Reconnaissance Orbiter captured this image of a network of spiderweb-like ridges – called boxwork by scientists – on Mount Sharp in Gale Crater on Mars on December 10, 2006. Image via NASA/ JPL-Caltech/ University of Arizona.

Maneuvering through the ridges

For the rover, maneuvering through the boxwork ridges can be a bit tricky. The rover can roll across the tops of the ridges, but they are not much wider than the rover itself. Also, Curiosity can move down into the sandy areas between the ridges, but it has to be careful not to get stuck. Operations systems engineer Ashley Stroupe at NASA’s Jet Propulsion Laboratory in Southern California is the Curiosity Rover Planner (Drive) team lead. She said:

It almost feels like a highway we can drive on. But then we have to go down into the hollows, where you need to be mindful of Curiosity’s wheels slipping or having trouble turning in the sand. There’s always a solution. It just takes trying different paths.

Operations systems engineer Ashley Stroupe at NASA’s Jet Propulsion Laboratory is the Curiosity Rover Planner (Drive) team lead. Image via NASA.

How did the boxwork ridges form?

The boxwork ridges are located on the slopes of Mount Sharp, which sits in the middle of Gale Crater and is about 3 miles (5 kilometers) tall. So, how did they form there? Similar formations exist on Earth, in fact, but they are usually only a few centimeters tall at most and found in caves or dry, sandy environments.

The higher elevations of Mount Sharp record a drier period in the history of Gale Crater, which was once a lake billions of years ago. The boxwork formations are surprisingly high up the mountain, however. Mission scientist Tina Seeger at Rice University in Houston, Texas, explained:

Seeing boxwork this far up the mountain suggests the groundwater table had to be pretty high. And that means the water needed for sustaining life could have lasted much longer than we thought looking from orbit.

In addition, orbiting spacecraft have also imaged the boxwork from high above. Intriguingly, the images showed dark lines going across the spiderwebs. Scientists said they were likely central fractures. That’s where the groundwater would have seeped up to the surface. Now, seeing them up close, Curiosity has confirmed they are indeed fractures.

Nodules in the spiderwebs

Additionally, Curiosity has also found other evidence for past groundwater in this region. For example, some of the rocks have bumpy textures comprised of small nodules. But there is another mystery to be solved, too. The nodules aren’t where scientists expected them to be, near the fractures. Instead, they’re along the walls of the ridges and on rocks in the sandy hollows. Seeger said:

We can’t quite explain yet why the nodules appear where they do. Maybe the ridges were cemented by minerals first, and later episodes of groundwater left nodules around them.

While the spiderwebs themselves have nothing to do with Martian life, they do provide new clues about water and habitable conditions in Mars’ past. What other discoveries might be hiding in the webs, waiting to be found?

View larger. | Closeup view of pea-sized nodules in the boxwork (spiderweb) formations. Groundwater formed them billions of years ago. Image via NASA/ JPL-Caltech/ MSSS.

Bottom line: NASA’s Curiosity rover has been investigating “spiderwebs” on Mars. Groundwater formed these grid-like formations of ridges billions of years ago.

Via NASA

Read more: Mars rover Curiosity heads for intriguing ‘spiderwebs’

Read more: Martian rock crushed by Curiosity hides a surprise!

The post Giant ‘spiderwebs’ on Mars reveal surprising water clues first appeared on EarthSky.

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Spectacular new Spinosaurus found in Niger, Africa

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

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

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

Newly discovered dinosaur had an eye-catching head crest

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

Sereno said:

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

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

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

This Spinosaurus was a dramatic-looking creature!

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

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

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

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

Finding a new Spinosaurus in Niger

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

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

He said:

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

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

Spinosaurus mirabilis

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

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

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

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

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

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

New clues to how spinosaurs lived

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

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

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

Sereno commented:

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

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

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

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

Via University of Chicago

Read more: The most exciting dinosaur discoveries of 2025

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

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

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

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

Newly discovered dinosaur had an eye-catching head crest

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

Sereno said:

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

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

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

This Spinosaurus was a dramatic-looking creature!

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

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

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

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

Finding a new Spinosaurus in Niger

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

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

He said:

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

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

Spinosaurus mirabilis

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

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

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

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

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

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

New clues to how spinosaurs lived

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

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

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

Sereno commented:

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

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

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

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

Via University of Chicago

Read more: The most exciting dinosaur discoveries of 2025

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

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Castor – the twin star – is 6 stars in one

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

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Castor, the less-bright Twin

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

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

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

And in 2026 Jupiter is nearby

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

Castor is a complex star system

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

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

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

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

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

Visualizing the separation of the stars

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

Another way to find the Twins

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

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

This line will point to Castor and Pollux.

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

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

Greek mythology of Castor and Pollux

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

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

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

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

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

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

Other stories surrounding the stars

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

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

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

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

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

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

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

from EarthSky https://ift.tt/U0uK3WD

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

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

Castor, the less-bright Twin

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

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

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

And in 2026 Jupiter is nearby

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

Castor is a complex star system

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

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

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

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

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

Visualizing the separation of the stars

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

Another way to find the Twins

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

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

This line will point to Castor and Pollux.

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

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

Greek mythology of Castor and Pollux

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

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

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

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

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

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

Other stories surrounding the stars

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

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

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

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

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

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

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

from EarthSky https://ift.tt/U0uK3WD