Gladiator bones show first-ever evidence of lion mauling

A Roman gladiator uncovered in York, England, shows physical evidence of bite marks, indicating he may have been killed by a lion. The paper’s lead author, Tim Thompson, discusses the findings in this video.

Scientists found bite marks, likely from a lion, on the pelvis of a Roman gladiator in England.

The skeleton was from a known gladiator cemetery in York, confirming that human versus wild animal fights occurred far beyond Rome.

The bite marks had not healed, suggesting that the gladiator died not long after the attack.

First physical evidence of a gladiator attacked by a lion

Gladiators were armed men who fought each other, and sometimes wild animals, to entertain audiences in the Roman Empire. Images of gladiators bitten by wild animals have appeared in ancient artwork and in written accounts. On April 23, 2025, scientists announced they had discovered, for the first time, physical evidence of bite marks on the skeleton of a gladiator. They said it came from a big cat, most likely a lion. This skeleton was found at Driffield Terrace, a well-preserved gladiator cemetery outside York, England.

The researchers announced their findings in the peer-reviewed journal PLOS One on April 23, 2025.

Tim Thompson of Maynooth University, Ireland, is the paper’s lead author, He said in a statement:

For years, our understanding of Roman gladiatorial combat and animal spectacles has relied heavily on historical texts and artistic depictions. This discovery provides the first direct, physical evidence that such events took place in this period, reshaping our perception of Roman entertainment culture in the region.

This skeleton of a gladiator had unhealed bite marks in its pelvis. Scientists think that he fought a lion in an arena, in front of an audience, and may have been killed by the animal. Image via University of York.

Analyzing bite marks on the gladiator’s pelvic bone

The bite marks on the pelvis had not healed, indicating that the gladiator died not long after the attack. What kind of carnivore attacked him? To find out, the scientists obtained detailed images of the marks. Next, they acquired sample bite marks from several big carnivorous animals, like lions, tigers, and wolves. Then, they compared the shape and size of those sample bite marks to those found on the gladiator. The closest bite mark match was from big cats, most likely a lion.

Malin Holst, at the University of York, is a paper co-author. She commented in the statement:

The bite marks were likely made by a lion, which confirms that the skeletons buried at the cemetery were gladiators, rather than soldiers or slaves, as initially thought and represent the first osteological [research based on the study of bones] confirmation of human interaction with large carnivores in a combat or entertainment setting in the Roman world.

Bite marks on the left iliac spine, a part of the pelvis. Image via Thompson, T. J. U., et al. / PLOSOne. (CC BY 4.0)

Bite marks on the right ilium, a part of the pelvis. Image via Thompson, T. J. U., et al. / PLOSOne. (CC BY 4.0)

Using the evidence to tell a story

Accounts of human-animal fights in the Roman Empire have been recorded in historical writings, as well as artwork such as mosaics, pottery, and carvings. And now, there is physical evidence of it on a gladiator’s skeleton.

Holst added:

This is a hugely exciting find because we can now start to build a better image of what these gladiators were like in life, and it also confirms the presence of large cats, and potentially other exotic animals, in arenas in cities such as York, and how they too had to defend themselves from the threat of death.

We often have a mental image of these combats occurring at the grand surroundings of the Colosseum in Rome, but these latest findings show that these sporting events had a far reach, well beyond the center of core Roman territories. An amphitheater probably existed in Roman York, but this has not yet been discovered.

This new evidence has also opened up new questions. For instance, how did the Romans transport a lion all the way from Africa to England?

A partial marble relief showing a fight between a gladiator and a lion, found in Turkey. It was inscribed in Greek: “’Second [fight] … fourth [fight]. He was taken away for burial.” Image via The British Museum (CC BY-NC-SA 4.0)

What scientists have learned about the gladiator

The researchers learned a lot about this gladiator from an examination of his skeleton. He was a young male, about 5 feet 8 inches (171.9 cm) tall. At the time of death, he was between 26 and 35 years old. He was buried between 200 to 300 CE (1,825 to 1,725 years ago) near York.

A study of his bones revealed several ailments. He had spinal issues, possibly due to carrying too much on his back. There were signs of inflammation in his lungs and one thigh. And as a child, he suffered from malnutrition but later recovered from it.

This gladiator was one of 82 skeletons, mostly young strongly built men, who were found at the 1,800-year-old Driffield Terrace site. The other skeletons also showed signs of trauma, suggesting it was a gladiator graveyard.

The lion bite marks had not healed, indicating that he died as a result of, or shortly after the attack. In addition, he had been decapitated, as was a large number of other skeletons at Driffield Terrace. The researchers suggested two possibilities for the decapitation. It may have been done to put him out of his misery following the lion attack. Or it may have been a post-death ritual.

This gladiator was then buried with two others in a grave. Bones from a horse were found over them.

York in Roman times

The ancient Roman Empire once ruled much of Europe, western Asia, and North Africa, from 27 BCE to 476 CE (2,052 to 1,549 years ago). It cast a great cultural influence over this vast region. As a result, gladiatorial events became widespread throughout the Roman Empire. England, in particular, was occupied by Romans from the first to fifth centuries.

York, then known as Eboracum, had many high-ranking generals and politicians as late as the fourth century CE. They included Constantine, who appointed himself emperor of the Roman Empire in 306 CE. The presence of so many senior leaders in Eboracum suggests that they probably led a lavish lifestyle, which would have included gladiatorial events.

Bottom line: Scientists have found, for the first time, physical evidence of bite marks from a big cat, likely a lion, on the skeleton of a gladiator.

Source: Unique osteological evidence for human-animal gladiatorial combat in Roman Britain

Via University of York

Via Maynooth University

Read more: What is the Common Era?

The post Gladiator bones show first-ever evidence of lion mauling first appeared on EarthSky.

from EarthSky https://ift.tt/bgIsvBT

A Roman gladiator uncovered in York, England, shows physical evidence of bite marks, indicating he may have been killed by a lion. The paper’s lead author, Tim Thompson, discusses the findings in this video.

Scientists found bite marks, likely from a lion, on the pelvis of a Roman gladiator in England.

The skeleton was from a known gladiator cemetery in York, confirming that human versus wild animal fights occurred far beyond Rome.

The bite marks had not healed, suggesting that the gladiator died not long after the attack.

First physical evidence of a gladiator attacked by a lion

Gladiators were armed men who fought each other, and sometimes wild animals, to entertain audiences in the Roman Empire. Images of gladiators bitten by wild animals have appeared in ancient artwork and in written accounts. On April 23, 2025, scientists announced they had discovered, for the first time, physical evidence of bite marks on the skeleton of a gladiator. They said it came from a big cat, most likely a lion. This skeleton was found at Driffield Terrace, a well-preserved gladiator cemetery outside York, England.

The researchers announced their findings in the peer-reviewed journal PLOS One on April 23, 2025.

Tim Thompson of Maynooth University, Ireland, is the paper’s lead author, He said in a statement:

For years, our understanding of Roman gladiatorial combat and animal spectacles has relied heavily on historical texts and artistic depictions. This discovery provides the first direct, physical evidence that such events took place in this period, reshaping our perception of Roman entertainment culture in the region.

This skeleton of a gladiator had unhealed bite marks in its pelvis. Scientists think that he fought a lion in an arena, in front of an audience, and may have been killed by the animal. Image via University of York.

Analyzing bite marks on the gladiator’s pelvic bone

The bite marks on the pelvis had not healed, indicating that the gladiator died not long after the attack. What kind of carnivore attacked him? To find out, the scientists obtained detailed images of the marks. Next, they acquired sample bite marks from several big carnivorous animals, like lions, tigers, and wolves. Then, they compared the shape and size of those sample bite marks to those found on the gladiator. The closest bite mark match was from big cats, most likely a lion.

Malin Holst, at the University of York, is a paper co-author. She commented in the statement:

The bite marks were likely made by a lion, which confirms that the skeletons buried at the cemetery were gladiators, rather than soldiers or slaves, as initially thought and represent the first osteological [research based on the study of bones] confirmation of human interaction with large carnivores in a combat or entertainment setting in the Roman world.

Bite marks on the left iliac spine, a part of the pelvis. Image via Thompson, T. J. U., et al. / PLOSOne. (CC BY 4.0)

Bite marks on the right ilium, a part of the pelvis. Image via Thompson, T. J. U., et al. / PLOSOne. (CC BY 4.0)

Using the evidence to tell a story

Accounts of human-animal fights in the Roman Empire have been recorded in historical writings, as well as artwork such as mosaics, pottery, and carvings. And now, there is physical evidence of it on a gladiator’s skeleton.

Holst added:

This is a hugely exciting find because we can now start to build a better image of what these gladiators were like in life, and it also confirms the presence of large cats, and potentially other exotic animals, in arenas in cities such as York, and how they too had to defend themselves from the threat of death.

We often have a mental image of these combats occurring at the grand surroundings of the Colosseum in Rome, but these latest findings show that these sporting events had a far reach, well beyond the center of core Roman territories. An amphitheater probably existed in Roman York, but this has not yet been discovered.

This new evidence has also opened up new questions. For instance, how did the Romans transport a lion all the way from Africa to England?

A partial marble relief showing a fight between a gladiator and a lion, found in Turkey. It was inscribed in Greek: “’Second [fight] … fourth [fight]. He was taken away for burial.” Image via The British Museum (CC BY-NC-SA 4.0)

What scientists have learned about the gladiator

The researchers learned a lot about this gladiator from an examination of his skeleton. He was a young male, about 5 feet 8 inches (171.9 cm) tall. At the time of death, he was between 26 and 35 years old. He was buried between 200 to 300 CE (1,825 to 1,725 years ago) near York.

A study of his bones revealed several ailments. He had spinal issues, possibly due to carrying too much on his back. There were signs of inflammation in his lungs and one thigh. And as a child, he suffered from malnutrition but later recovered from it.

This gladiator was one of 82 skeletons, mostly young strongly built men, who were found at the 1,800-year-old Driffield Terrace site. The other skeletons also showed signs of trauma, suggesting it was a gladiator graveyard.

The lion bite marks had not healed, indicating that he died as a result of, or shortly after the attack. In addition, he had been decapitated, as was a large number of other skeletons at Driffield Terrace. The researchers suggested two possibilities for the decapitation. It may have been done to put him out of his misery following the lion attack. Or it may have been a post-death ritual.

This gladiator was then buried with two others in a grave. Bones from a horse were found over them.

York in Roman times

The ancient Roman Empire once ruled much of Europe, western Asia, and North Africa, from 27 BCE to 476 CE (2,052 to 1,549 years ago). It cast a great cultural influence over this vast region. As a result, gladiatorial events became widespread throughout the Roman Empire. England, in particular, was occupied by Romans from the first to fifth centuries.

York, then known as Eboracum, had many high-ranking generals and politicians as late as the fourth century CE. They included Constantine, who appointed himself emperor of the Roman Empire in 306 CE. The presence of so many senior leaders in Eboracum suggests that they probably led a lavish lifestyle, which would have included gladiatorial events.

Bottom line: Scientists have found, for the first time, physical evidence of bite marks from a big cat, likely a lion, on the skeleton of a gladiator.

Source: Unique osteological evidence for human-animal gladiatorial combat in Roman Britain

Via University of York

Via Maynooth University

Read more: What is the Common Era?

The post Gladiator bones show first-ever evidence of lion mauling first appeared on EarthSky.

from EarthSky https://ift.tt/bgIsvBT

New study says rain on ancient Mars fed rivers and lakes

View larger. | Artist’s concept of the river that once flowed into Gale crater on Mars, forming a lake. Did it also rain on ancient Mars? A new study suggests that heavy precipitation – rain or snow – fed the rivers and lakes on Mars billions of years ago. Image via Kevin Gill/ Flickr.

Looking up has never felt more important.
Please donate to help EarthSky keep bringing the sky to your screen.

• Mars is an extremely dry desert world, with no liquid water on its surface. But was it always that way? Ancient now-dry riverbeds and lakebeds show that Mars was once brimming with water. How did they form?
• Heavy precipitation – rain or snow – created Mars’ river systems that fed the lakes, a new study shows.
• Scientists used a computer simulation to compare erosion from rain or snow to melting ice. The rain or snow model best explained the erosion features still seen on Mars today.

Did it rain on ancient Mars?

Mars today is a bone-dry desert world. But a few billion years ago, you could have played in rain puddles or perhaps a snowbank. That’s the conclusion of a new study from researchers at the University of Colorado Boulder. The geologists said on April 21, 2025, that heavy precipitation – either rain or snow or both – likely formed and fed many of the river channels and valleys that we can still see clearly etched into the Martian surface. The new evidence supports the scenario that early Mars was at least relatively warm and wet.

The researchers published their peer-reviewed findings in the Journal of Geophysical Research: Planets on April 21, 2025.

Warm and wet or cold and dry?

The findings add to the debate of whether Mars was always cold and dry or if it was warmer and wetter billions of years ago. Some scientists think it was warmer, while others say it was cold. Even after decades of research and exploration of Mars by rovers and landers, they have not come to a consensus.

We know that Mars has long had abundant ice, both at its poles and underground, but was that water ever liquid? Ancient riverbeds, lake deposits and even possible ocean sediments – and vacation-style beaches – suggest it was. But how?

Jezero crater, which NASA’s Perseverance rover is exploring, was once a lake. Like Gale crater, a river once flowed into this lake. The rover has studied the ancient river delta inside the crater, which we can still easily see from orbit. Perseverance found large boulders that the river transported. And that required a lot of water. Co-author Brian Hynek at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder said:

You’d need meters deep of flowing water to deposit those kinds of boulders.

A digital simulation of Mars

It’s apparent that Mars was once awash in water. And not just as frozen ice. Lead author Amanda Steckel was at the University of Colorado Boulder for the study and is now at the California Institute of Technology (Caltech). She said:

It’s very hard to make any kind of conclusive statement, but we see these valleys beginning at a large range of elevations. It’s hard to explain that with just ice. You could pull up Google Earth images of places like Utah, zoom out, and you’d see the similarities to Mars.

Watch: Earth or Mars? Test yourself with this quick quiz

Amanda Steckel, formerly at the University of Colorado Boulder and now at Caltech, is the lead author of the new study about Martian rain and snow. Image via Caltech.

Ice or snow or rain on ancient Mars?

For their own study, the researchers used digital computer simulations to see how water would have shaped the Martian surface. Did rain or snow help form the channels and valleys, or was it just melting ice? The study suggests it was indeed rain or snow. Co-author Gregory Tucker at the Department of Geological Sciences at the University of Colorado Boulder originally developed this simulation model for Earth studies.

The model simulated terrain close to the Martian equator, where many of the old river channels can be found. In the simulation, water was added in two different ways, both as rain or snow and as ice. In addition, the researchers even simulated melting ice caps. The model simulated the flows of water for periods of tens to hundreds of thousands of years.

Strikingly different results

The simulations provided markedly different results depending whether the water was precipitation or melting ice. For example, with melting ice caps, the river valleys created were mostly at high elevations. They were also limited to the terrain around the edge of the melting polar ice cap. But it was different for the valleys created by precipitation, whether rain or snow. They were more widespread and at various elevations. Some were below the average surface elevation, while others formed at elevations up to 11,000 feet (3,300 meters).

Steckel said:

Water from these ice caps starts to form valleys only around a narrow band of elevations. Whereas if you have distributed precipitation, you can have valley heads forming everywhere.

So which scenario is closer to what we actually see on Mars? The precipitation one. The ancient riverbeds we see today are largely around the equator, far from where any meltwater from the ice caps would have flowed, and vary in elevation.

View larger. | This topographic map from NASA’s Mars Global Surveyor shows a region of Mars near the equator. Many of the ancient riverbeds are in the equatorial region of Mars. Image via NASA/ University of Colorado Boulder.

How did Mars stay warm?

The results are yet more evidence for a much wetter Mars in the past. Scientists still don’t know exactly how the planet was able to maintain the warmth needed for as long as it did. But the Curiosity rover might have just helped that mystery, too. Another recent study focused on siderite carbonates the rover has found in Gale crater. They are evidence that Mars used to have a carbon cycle similar to that on Earth, and that the carbon dioxide atmosphere used to be much thicker and warmer than it is today. Liquid water could have been abundant in those conditions.

But those conditions didn’t last, and Mars lost most of its atmosphere and water. As Hynek noted:

Once the erosion from flowing water stopped, Mars almost got frozen in time and probably still looks a lot like Earth did 3.5 billion years ago.

Incidentally, it does still snow on Mars today. The Mars Phoenix lander recorded snow falling from clouds, NASA reported in 2008. In Mars’ really thin atmosphere, however, the snowflakes evaporated before reaching the ground, at least in this location.

Bottom line: Did it rain on ancient Mars? A new study suggests that heavy precipitation – rain or snow – helped form rivers that fed into lakes billions of years ago.

Source: Landscape Evolution Models of Incision on Mars: Implications for the Ancient Climate

Via University of Colorado Boulder

Read more: How hard did it rain on Mars?

Read more: New discovery of carbonates on Mars could solve big mystery

The post New study says rain on ancient Mars fed rivers and lakes first appeared on EarthSky.

from EarthSky https://ift.tt/H2bskpo

View larger. | Artist’s concept of the river that once flowed into Gale crater on Mars, forming a lake. Did it also rain on ancient Mars? A new study suggests that heavy precipitation – rain or snow – fed the rivers and lakes on Mars billions of years ago. Image via Kevin Gill/ Flickr.

Looking up has never felt more important.
Please donate to help EarthSky keep bringing the sky to your screen.

• Mars is an extremely dry desert world, with no liquid water on its surface. But was it always that way? Ancient now-dry riverbeds and lakebeds show that Mars was once brimming with water. How did they form?
• Heavy precipitation – rain or snow – created Mars’ river systems that fed the lakes, a new study shows.
• Scientists used a computer simulation to compare erosion from rain or snow to melting ice. The rain or snow model best explained the erosion features still seen on Mars today.

Did it rain on ancient Mars?

Mars today is a bone-dry desert world. But a few billion years ago, you could have played in rain puddles or perhaps a snowbank. That’s the conclusion of a new study from researchers at the University of Colorado Boulder. The geologists said on April 21, 2025, that heavy precipitation – either rain or snow or both – likely formed and fed many of the river channels and valleys that we can still see clearly etched into the Martian surface. The new evidence supports the scenario that early Mars was at least relatively warm and wet.

The researchers published their peer-reviewed findings in the Journal of Geophysical Research: Planets on April 21, 2025.

Warm and wet or cold and dry?

The findings add to the debate of whether Mars was always cold and dry or if it was warmer and wetter billions of years ago. Some scientists think it was warmer, while others say it was cold. Even after decades of research and exploration of Mars by rovers and landers, they have not come to a consensus.

We know that Mars has long had abundant ice, both at its poles and underground, but was that water ever liquid? Ancient riverbeds, lake deposits and even possible ocean sediments – and vacation-style beaches – suggest it was. But how?

Jezero crater, which NASA’s Perseverance rover is exploring, was once a lake. Like Gale crater, a river once flowed into this lake. The rover has studied the ancient river delta inside the crater, which we can still easily see from orbit. Perseverance found large boulders that the river transported. And that required a lot of water. Co-author Brian Hynek at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder said:

You’d need meters deep of flowing water to deposit those kinds of boulders.

A digital simulation of Mars

It’s apparent that Mars was once awash in water. And not just as frozen ice. Lead author Amanda Steckel was at the University of Colorado Boulder for the study and is now at the California Institute of Technology (Caltech). She said:

It’s very hard to make any kind of conclusive statement, but we see these valleys beginning at a large range of elevations. It’s hard to explain that with just ice. You could pull up Google Earth images of places like Utah, zoom out, and you’d see the similarities to Mars.

Watch: Earth or Mars? Test yourself with this quick quiz

Amanda Steckel, formerly at the University of Colorado Boulder and now at Caltech, is the lead author of the new study about Martian rain and snow. Image via Caltech.

Ice or snow or rain on ancient Mars?

For their own study, the researchers used digital computer simulations to see how water would have shaped the Martian surface. Did rain or snow help form the channels and valleys, or was it just melting ice? The study suggests it was indeed rain or snow. Co-author Gregory Tucker at the Department of Geological Sciences at the University of Colorado Boulder originally developed this simulation model for Earth studies.

The model simulated terrain close to the Martian equator, where many of the old river channels can be found. In the simulation, water was added in two different ways, both as rain or snow and as ice. In addition, the researchers even simulated melting ice caps. The model simulated the flows of water for periods of tens to hundreds of thousands of years.

Strikingly different results

The simulations provided markedly different results depending whether the water was precipitation or melting ice. For example, with melting ice caps, the river valleys created were mostly at high elevations. They were also limited to the terrain around the edge of the melting polar ice cap. But it was different for the valleys created by precipitation, whether rain or snow. They were more widespread and at various elevations. Some were below the average surface elevation, while others formed at elevations up to 11,000 feet (3,300 meters).

Steckel said:

Water from these ice caps starts to form valleys only around a narrow band of elevations. Whereas if you have distributed precipitation, you can have valley heads forming everywhere.

So which scenario is closer to what we actually see on Mars? The precipitation one. The ancient riverbeds we see today are largely around the equator, far from where any meltwater from the ice caps would have flowed, and vary in elevation.

View larger. | This topographic map from NASA’s Mars Global Surveyor shows a region of Mars near the equator. Many of the ancient riverbeds are in the equatorial region of Mars. Image via NASA/ University of Colorado Boulder.

How did Mars stay warm?

The results are yet more evidence for a much wetter Mars in the past. Scientists still don’t know exactly how the planet was able to maintain the warmth needed for as long as it did. But the Curiosity rover might have just helped that mystery, too. Another recent study focused on siderite carbonates the rover has found in Gale crater. They are evidence that Mars used to have a carbon cycle similar to that on Earth, and that the carbon dioxide atmosphere used to be much thicker and warmer than it is today. Liquid water could have been abundant in those conditions.

But those conditions didn’t last, and Mars lost most of its atmosphere and water. As Hynek noted:

Once the erosion from flowing water stopped, Mars almost got frozen in time and probably still looks a lot like Earth did 3.5 billion years ago.

Incidentally, it does still snow on Mars today. The Mars Phoenix lander recorded snow falling from clouds, NASA reported in 2008. In Mars’ really thin atmosphere, however, the snowflakes evaporated before reaching the ground, at least in this location.

Bottom line: Did it rain on ancient Mars? A new study suggests that heavy precipitation – rain or snow – helped form rivers that fed into lakes billions of years ago.

Source: Landscape Evolution Models of Incision on Mars: Implications for the Ancient Climate

Via University of Colorado Boulder

Read more: How hard did it rain on Mars?

Read more: New discovery of carbonates on Mars could solve big mystery

The post New study says rain on ancient Mars fed rivers and lakes first appeared on EarthSky.

from EarthSky https://ift.tt/H2bskpo

NASA orbiter spots Curiosity rover making tracks on Mars

NASA’s Curiosity rover appears as a dark speck (bottom center) in this contrast-enhanced view captured on February 28, 2025, by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Trailing Curiosity are the rover’s tracks, which can linger on the Martian surface for months before being erased by the wind. Image via NASA/ JPL-Caltech/ University of Arizona.

• The Curiosity rover has been exploring Mars’ surface since 2012. The rover is currently on the way to its next science mission.
• Meanwhile, the Mars Reconnaissance Orbiter has been circling Mars high overhead since 2006. It has caught the rover below on numerous occasions.
• But this is the first time the orbiter captured the rover while it was on the move. In the image, you can see the tracks laid out in the Martian soil behind the little rover.

NASA published this original story on April 24, 2025. Edits by EarthSky.

NASA orbiter spots Curiosity rover making tracks on Mars

The image marks what may be the first time one of the agency’s Mars orbiters has captured the rover driving.

NASA’s Curiosity Mars rover has never been camera shy, having been seen in selfies and images taken from space. But on February 28 — the 4,466th Martian day, or sol, of the mission — Curiosity was captured in what is believed to be the first orbital image of the rover mid-drive across the red planet.

Taken by the HiRISE (High-Resolution Imaging Science Experiment) camera aboard NASA’s Mars Reconnaissance Orbiter, the image shows Curiosity as a dark speck at the front of a long trail of rover tracks. Likely to last for months before being erased by wind, the tracks span about 1,050 feet (320 meters). They represent roughly 11 drives starting on February 2 as Curiosity trucked along at a top speed of 0.1 mph (0.16 kph) from Gediz Vallis channel on the journey to its next science stop: a region with potential boxwork formations, possibly made by groundwater billions of years ago.

The next stop for Curiosity

How quickly the rover reaches the area depends on a number of factors, including how its software navigates the surface and how challenging the terrain is to climb. Engineers at NASA’s Jet Propulsion Laboratory in Southern California, which leads Curiosity’s mission, work with scientists to plan each day’s trek.

Doug Ellison, Curiosity’s planning team chief at JPL, said:

By comparing the time HiRISE took the image to the rover’s commands for the day, we can see it was nearly done with a 69-foot drive.

Designed to ensure the best spatial resolution, HiRISE takes an image with the majority of the scene in black and white and a strip of color down the middle. While the camera has captured Curiosity in color before, this time the rover happened to fall within the black-and-white part of the image.

In the new image, Curiosity’s tracks lead to the base of a steep slope. The rover has ascended that slope since then, and it is expected to reach its new science location within a month or so.

Bottom line: A spacecraft orbiting Mars has caught the Curiosity rover in action as it drives to its next science mission.

Via NASA

Read more: Morning and afternoon on Mars, from Curiosity rover

The post NASA orbiter spots Curiosity rover making tracks on Mars first appeared on EarthSky.

from EarthSky https://ift.tt/AteKiQw

NASA’s Curiosity rover appears as a dark speck (bottom center) in this contrast-enhanced view captured on February 28, 2025, by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. Trailing Curiosity are the rover’s tracks, which can linger on the Martian surface for months before being erased by the wind. Image via NASA/ JPL-Caltech/ University of Arizona.

• The Curiosity rover has been exploring Mars’ surface since 2012. The rover is currently on the way to its next science mission.
• Meanwhile, the Mars Reconnaissance Orbiter has been circling Mars high overhead since 2006. It has caught the rover below on numerous occasions.
• But this is the first time the orbiter captured the rover while it was on the move. In the image, you can see the tracks laid out in the Martian soil behind the little rover.

NASA published this original story on April 24, 2025. Edits by EarthSky.

NASA orbiter spots Curiosity rover making tracks on Mars

The image marks what may be the first time one of the agency’s Mars orbiters has captured the rover driving.

NASA’s Curiosity Mars rover has never been camera shy, having been seen in selfies and images taken from space. But on February 28 — the 4,466th Martian day, or sol, of the mission — Curiosity was captured in what is believed to be the first orbital image of the rover mid-drive across the red planet.

Taken by the HiRISE (High-Resolution Imaging Science Experiment) camera aboard NASA’s Mars Reconnaissance Orbiter, the image shows Curiosity as a dark speck at the front of a long trail of rover tracks. Likely to last for months before being erased by wind, the tracks span about 1,050 feet (320 meters). They represent roughly 11 drives starting on February 2 as Curiosity trucked along at a top speed of 0.1 mph (0.16 kph) from Gediz Vallis channel on the journey to its next science stop: a region with potential boxwork formations, possibly made by groundwater billions of years ago.

The next stop for Curiosity

How quickly the rover reaches the area depends on a number of factors, including how its software navigates the surface and how challenging the terrain is to climb. Engineers at NASA’s Jet Propulsion Laboratory in Southern California, which leads Curiosity’s mission, work with scientists to plan each day’s trek.

Doug Ellison, Curiosity’s planning team chief at JPL, said:

By comparing the time HiRISE took the image to the rover’s commands for the day, we can see it was nearly done with a 69-foot drive.

Designed to ensure the best spatial resolution, HiRISE takes an image with the majority of the scene in black and white and a strip of color down the middle. While the camera has captured Curiosity in color before, this time the rover happened to fall within the black-and-white part of the image.

In the new image, Curiosity’s tracks lead to the base of a steep slope. The rover has ascended that slope since then, and it is expected to reach its new science location within a month or so.

Bottom line: A spacecraft orbiting Mars has caught the Curiosity rover in action as it drives to its next science mission.

Via NASA

Read more: Morning and afternoon on Mars, from Curiosity rover

The post NASA orbiter spots Curiosity rover making tracks on Mars first appeared on EarthSky.

from EarthSky https://ift.tt/AteKiQw

Hercules is between 2 bright stars: Vega and Arcturus

Hercules is a faint constellation. But its mid-section contains the easy-to-see Keystone asterism. In order to find it, look for it between the bright stars Vega in Lyra the Harp and Arcturus in Boötes the Herdsman. Chart via EarthSky.

Finding Hercules

Tonight, try locating one of the coolest constellations up there. It’s the constellation Hercules the Strongman and it’s ascending in the east-northeast on these Northern Hemisphere spring evenings. You can find it between two brilliant stars, Arcturus and Vega. The chart at the top of this post shows the evening sky in late April, when the constellation Hercules, and the two stars so essential for finding it, are well up in the northeastern to eastern sky.

Arcturus is in the constellation Boötes, and Vega is in the constellation Lyra. However, at nightfall, Vega may still be below your horizon. If so, wait a while … it’ll rise soon.

Then if you draw a line between Arcturus and Vega, it’ll pass through what is known as the Keystone – an asterism, or noticeable star pattern – in Hercules. The Keystone is a squarish figure in the center of Hercules. See it on the charts above and below?

Before you can find M13, you need to find the Keystone in Hercules, a pattern of 4 stars. So as darkness falls, look for the Keystone to the upper right of the brilliant star Vega. Chart via EarthSky.

The Keystone guides you to M13

Furthermore, the Keystone is a helpful pattern for more reasons than one. First, it’s noticeable on the sky’s dome, so it can lead your eye to Hercules.

Second, the Keystone can help you find the most fascinating telescopic object within the boundaries of this constellation. This object is a globular star cluster known to stargazers as M13 or the Great Cluster. Although M13 is barely visible to the eye alone in dark skies, binoculars reveal a nebulous starlike patch of light. And telescopes show stars both on the periphery of the cluster and toward its center.

Chart showing M13 (the great Hercules cluster) in the Keystone. And M92 is above the Keystone. Image via Wikipedia.

Undoubtedly, this beautiful object is one of the galaxy’s oldest inhabitants. It’s a tightly packed spherical collection of about one million stars.

Read more: M13 or the Great Cluster in Hercules

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

M13, aka the Great Cluster. This object is a globular star cluster, one of our galaxy’s oldest inhabitants. Photo via ESA/ Hubble/ NASA.

But wait, there’s more

Although it’s not as spectacular as M13, Hercules has another great globular cluster, M92. It makes a triangle with the two northernmost stars in the Keystone. So imagine it is where Hercules’ head would be. Even though you can marginally see it without optical aid, it shows up easily in binoculars and a telescope.

Bottom line: Tonight, if you look between the brilliant stars Arcturus and Vega, you can find the constellation Hercules. And look for its two fabulous globular clusters easily found in binoculars.

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The post Hercules is between 2 bright stars: Vega and Arcturus first appeared on EarthSky.

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Hercules is a faint constellation. But its mid-section contains the easy-to-see Keystone asterism. In order to find it, look for it between the bright stars Vega in Lyra the Harp and Arcturus in Boötes the Herdsman. Chart via EarthSky.

Finding Hercules

Tonight, try locating one of the coolest constellations up there. It’s the constellation Hercules the Strongman and it’s ascending in the east-northeast on these Northern Hemisphere spring evenings. You can find it between two brilliant stars, Arcturus and Vega. The chart at the top of this post shows the evening sky in late April, when the constellation Hercules, and the two stars so essential for finding it, are well up in the northeastern to eastern sky.

Arcturus is in the constellation Boötes, and Vega is in the constellation Lyra. However, at nightfall, Vega may still be below your horizon. If so, wait a while … it’ll rise soon.

Then if you draw a line between Arcturus and Vega, it’ll pass through what is known as the Keystone – an asterism, or noticeable star pattern – in Hercules. The Keystone is a squarish figure in the center of Hercules. See it on the charts above and below?

Before you can find M13, you need to find the Keystone in Hercules, a pattern of 4 stars. So as darkness falls, look for the Keystone to the upper right of the brilliant star Vega. Chart via EarthSky.

The Keystone guides you to M13

Furthermore, the Keystone is a helpful pattern for more reasons than one. First, it’s noticeable on the sky’s dome, so it can lead your eye to Hercules.

Second, the Keystone can help you find the most fascinating telescopic object within the boundaries of this constellation. This object is a globular star cluster known to stargazers as M13 or the Great Cluster. Although M13 is barely visible to the eye alone in dark skies, binoculars reveal a nebulous starlike patch of light. And telescopes show stars both on the periphery of the cluster and toward its center.

Chart showing M13 (the great Hercules cluster) in the Keystone. And M92 is above the Keystone. Image via Wikipedia.

Undoubtedly, this beautiful object is one of the galaxy’s oldest inhabitants. It’s a tightly packed spherical collection of about one million stars.

Read more: M13 or the Great Cluster in Hercules

EarthSky astronomy kits are perfect for beginners. Order today from the EarthSky store

M13, aka the Great Cluster. This object is a globular star cluster, one of our galaxy’s oldest inhabitants. Photo via ESA/ Hubble/ NASA.

But wait, there’s more

Although it’s not as spectacular as M13, Hercules has another great globular cluster, M92. It makes a triangle with the two northernmost stars in the Keystone. So imagine it is where Hercules’ head would be. Even though you can marginally see it without optical aid, it shows up easily in binoculars and a telescope.

Bottom line: Tonight, if you look between the brilliant stars Arcturus and Vega, you can find the constellation Hercules. And look for its two fabulous globular clusters easily found in binoculars.

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

The post Hercules is between 2 bright stars: Vega and Arcturus first appeared on EarthSky.

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Chimpanzees know how to party. Boozy fruit, anybody?

Chimpanzees sharing fruit. Image via Anna Bowland/ Cantanhez Chimpanzee Project/ University of Exeter.

Chimps eat and share boozy fruit

Remote cameras in Guinea-Bissau’s Cantanhez National Park in Africa have captured a fascinating behavior of wild chimpanzees. A team of scientists from the University of Exeter said on April 21, 2025, that for the first time they’ve documented chimps repeatedly eating and sharing naturally fermented African breadfruit. The fermented fruit contains alcohol. So the scientists are now investigating whether alcohol consumption is conscious and, if it is, why they ingest it.

The scientists published their study in the peer-reviewed journal Science Direct on April 21, 2025.

How much alcohol do chimpanzees ingest?

Fermented fruit contains ethanol, an organic chemical compound that contains alcohol. Scientists analyzed the alcohol content of the fruit the chimpanzees were eating to determine how much alcohol they were ingesting. The highest level found was the equivalent of 0.61% ABV (Alcohol By Volume, a measurement used in alcoholic beverages).

This is a relatively low amount. However, chimpanzees’ diets are made up of 60-85% fruit. So even if the amount of alcohol is low, it would be increased if the chimpanzees ate a lot of the fruit that contained alcohol.

But scientists believe that chimpanzees do not get drunk, as this would significantly decrease their chances of survival.

Why do chimpanzees consume this fruit with alcohol?

Scientists emphasize that chimpanzees don’t always share food. Yet on 10 different occasions the researchers observed the chimps sharing fermented fruit. Is this perhaps a form of socializing? One of the co-authors of the study, Kimberley Hockings of the University of Exeter, said:

Chimps don’t share food all the time, so this behavior with fermented fruit might be important.

In humans, alcohol consumption causes the release of dopamine and endorphins, which, in turn, makes us feel more relaxed and happier. Although the specific impact of alcohol on chimpanzee metabolism is unknown, some interesting recent discoveries have been made.

The scientists said that a molecular adaptation that greatly increased ethanol metabolism in the common ancestor of African apes suggests that eating fermented fruits may have ancient origins in species including humans and chimpanzees.

Two adult males feed on fermented African breadfruit. Image via Anna Bowland/ University of Exeter.

Is alcohol a tool for socializing?

Humans have turned to alcohol throughout our history to socialize. Chimpanzees share 98% of their DNA with us; they use tools, have feelings, express themselves through vocalizations and gestures, and play.

So it’s possible that chimps consume alcohol occasionally for the same reasons we do. According to the lead author of the study, Anna Bowland, from the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall:

For humans, we know that drinking alcohol leads to a release of dopamine and endorphins, and resulting feelings of happiness and relaxation. We also know that sharing alcohol — including through traditions such as feasting — helps to form and strengthen social bonds. So now we know that wild chimpanzees are eating and sharing ethanolic fruits; the question is: could they be getting similar benefits?

More studies needed

If these animals deliberately gather to drink alcohol, share and celebrate, then alcoholic feasts are no longer traditions unique to humans.

It may be that from the beginning of our evolutionary history, alcohol was already present in the lives of our ancestors. Are chimpanzees the spitting image of our great-great-great-great-great-great-great-grandparents? Hockings said:

We need to find out more about whether they deliberately seek out ethanolic fruits and how they metabolize it, but this behavior could be the early evolutionary stages of ‘feasting.’ If so, it suggests the human tradition of feasting may have its origins deep in our evolutionary history.

Bottom line: Do chimpanzees meet in parties to ingest alcohol like we do? For the first time, scientists have recorded chimps repeatedly eating and sharing fermented fruit.

Source: Wild chimpanzees share fermented fruits

Via University of Exeter

Bonobo chatter shares a unique feature with human speech

Orphaned bonobos can develop social skills and empathy

The post Chimpanzees know how to party. Boozy fruit, anybody? first appeared on EarthSky.

from EarthSky https://ift.tt/5VQPnK0

Chimpanzees sharing fruit. Image via Anna Bowland/ Cantanhez Chimpanzee Project/ University of Exeter.

Chimps eat and share boozy fruit

Remote cameras in Guinea-Bissau’s Cantanhez National Park in Africa have captured a fascinating behavior of wild chimpanzees. A team of scientists from the University of Exeter said on April 21, 2025, that for the first time they’ve documented chimps repeatedly eating and sharing naturally fermented African breadfruit. The fermented fruit contains alcohol. So the scientists are now investigating whether alcohol consumption is conscious and, if it is, why they ingest it.

The scientists published their study in the peer-reviewed journal Science Direct on April 21, 2025.

How much alcohol do chimpanzees ingest?

Fermented fruit contains ethanol, an organic chemical compound that contains alcohol. Scientists analyzed the alcohol content of the fruit the chimpanzees were eating to determine how much alcohol they were ingesting. The highest level found was the equivalent of 0.61% ABV (Alcohol By Volume, a measurement used in alcoholic beverages).

This is a relatively low amount. However, chimpanzees’ diets are made up of 60-85% fruit. So even if the amount of alcohol is low, it would be increased if the chimpanzees ate a lot of the fruit that contained alcohol.

But scientists believe that chimpanzees do not get drunk, as this would significantly decrease their chances of survival.

Why do chimpanzees consume this fruit with alcohol?

Scientists emphasize that chimpanzees don’t always share food. Yet on 10 different occasions the researchers observed the chimps sharing fermented fruit. Is this perhaps a form of socializing? One of the co-authors of the study, Kimberley Hockings of the University of Exeter, said:

Chimps don’t share food all the time, so this behavior with fermented fruit might be important.

In humans, alcohol consumption causes the release of dopamine and endorphins, which, in turn, makes us feel more relaxed and happier. Although the specific impact of alcohol on chimpanzee metabolism is unknown, some interesting recent discoveries have been made.

The scientists said that a molecular adaptation that greatly increased ethanol metabolism in the common ancestor of African apes suggests that eating fermented fruits may have ancient origins in species including humans and chimpanzees.

Two adult males feed on fermented African breadfruit. Image via Anna Bowland/ University of Exeter.

Is alcohol a tool for socializing?

Humans have turned to alcohol throughout our history to socialize. Chimpanzees share 98% of their DNA with us; they use tools, have feelings, express themselves through vocalizations and gestures, and play.

So it’s possible that chimps consume alcohol occasionally for the same reasons we do. According to the lead author of the study, Anna Bowland, from the Centre for Ecology and Conservation at Exeter’s Penryn Campus in Cornwall:

For humans, we know that drinking alcohol leads to a release of dopamine and endorphins, and resulting feelings of happiness and relaxation. We also know that sharing alcohol — including through traditions such as feasting — helps to form and strengthen social bonds. So now we know that wild chimpanzees are eating and sharing ethanolic fruits; the question is: could they be getting similar benefits?

More studies needed

If these animals deliberately gather to drink alcohol, share and celebrate, then alcoholic feasts are no longer traditions unique to humans.

It may be that from the beginning of our evolutionary history, alcohol was already present in the lives of our ancestors. Are chimpanzees the spitting image of our great-great-great-great-great-great-great-grandparents? Hockings said:

We need to find out more about whether they deliberately seek out ethanolic fruits and how they metabolize it, but this behavior could be the early evolutionary stages of ‘feasting.’ If so, it suggests the human tradition of feasting may have its origins deep in our evolutionary history.

Bottom line: Do chimpanzees meet in parties to ingest alcohol like we do? For the first time, scientists have recorded chimps repeatedly eating and sharing fermented fruit.

Source: Wild chimpanzees share fermented fruits

Via University of Exeter

Bonobo chatter shares a unique feature with human speech

Orphaned bonobos can develop social skills and empathy

The post Chimpanzees know how to party. Boozy fruit, anybody? first appeared on EarthSky.

from EarthSky https://ift.tt/5VQPnK0

Want to find alien life? Look for patterns of energy

View larger/full image. | NASA’s Curiosity rover on Mars saw this little flower-like rock formation in 2022. It has a life-like quality about it, but it’s really just a small piece of rock sculpted by Martian winds. Now, a new theoretical study has explored the best ways to search for alien life. The study asks whether we will recognize life if and when we find it. And it suggests a novel way to search. Image via NASA/ JPL-Caltech/ MSSS.

Science matters. Wonder matters. You matter. Join our 2025 Donation Campaign today.

• Biosignatures are the big focus nowadays in the search for life on other worlds. Astronomers search for molecules – in the atmospheres of distant planets – indicating the presence of life.
• But would we recognize life-related molecules if we found them? What if, instead of looking for molecules, we looked for patterns of energy? For example, we might look for the conversion of high-energy compounds into low-energy compounds, a process shared by all life on Earth.
• A new study suggests that even exotic forms of life – ones that defy our imagination – might be discovered using this approach.

Seeking patterns of energy

The search for life elsewhere in the universe is a unique and broad challenge. Scientists think of exploring a previously habitable Mars or the potentially habitable oceans of Jupiter’s moon Europa or Saturn’s moon Enceladus. Or, in a way that’s only recently become possible via technological advances, they spend time with the James Webb Telescope or other telescopes analyzing the atmospheres of distant exoplanets, searching for biosignatures, that is, molecules in those planets’ atmospheres that would indicate the presence of life. But would alien life resemble life on Earth? Or might life on another world be unrecognizable?

Mikhail Tikhonov, an assistant professor of physics at Washington University in St. Louis, Missouri, is an expert on microbial communities. He said on April 10, 2025 – in an interview with his university – that, to find alien life, instead of seeking molecules known on Earth to be related to living organisms, we might try searching for life by looking for telltale patterns of energy.

What he means is this. Suppose we found something interesting in a Martian rock, or an unusual chemical signature in the atmosphere of a faraway world. Could we know for sure it was a life sign? As Tikhonov noted:

There could be life forms out there that defy our imagination.

He and his colleague Akshit Goyal, a scientist in India, suggest that patterns of energy are an alternative way, perhaps a more foolproof way, to seek life in the galaxy.

Tikhonov and Goyal published their peer-reviewed theoretical results in Nature Communications on March 28, 2025.

Life is life is life?

Tikhonov noted, for example, in the Washington University interview, that life on Earth is carbon-based. In other words, carbon is the fundamental building block of the complex molecules that make up all known life forms. But scientists and others sometimes speculate about silicon-based life. Silicon shares chemical properties with carbon. Like carbon, it can potentially support complex molecules, though with some drawbacks. Tikhonov said:

We don’t know anything about what alien life forms might look like or what they’re made of.

But there are two things everyone agrees on: Living things have to consume and transform energy, and they have to be able to replicate. That’s as close as we can get to a definition of life.

When looking for measurable biosignatures – or signatures of life on other worlds – we need to make additional assumptions. We are proposing that any living organism is extremely unlikely to be on its own. It will always be a part of an ecological community that is competing for resources.

In the search for life on Mars, for example, the focus is largely on finding organic molecules. But organic molecules, by themselves, are not proof of life. They can also form without life being involved at all. And would alien life even have the same molecules as life on Earth? Tikhonov said:

But more importantly, there is no reason to believe that an alien life form would have to be using the same molecules we do.

Mikhail Tikhonov is a co-author of the new theoretical study about alien life. Image via Washington University in St. Louis.

Patterns of energy

So, is there another way to search for alien life? Tikhonov and Goyal think so. Instead of looking for specific molecules by themselves, they recommend looking for patterns of energy among many molecules. What do they mean by that? Basically, these patterns of energy arise the process of breaking down high-energy compounds, such as glucose, into low-energy compounds, like carbon dioxide. It’s the process of that energy change that is a telltale marker of life. As Tikhonov explained:

Life is incentivized to break down high-energy compounds first. Organisms that consume more energy-rich resources will outcompete and displace others, leading to a particular kind of layering, with compounds arranged by decreasing energy content. It doesn’t matter what the organisms look like. As long as you have self-replication and ecological competition, we expect this pattern to form.

Layered structures can be generated by many processes, both living and non-living. But only life cares about energy in this way, so energy-ordered layering would be special. On Earth, such patterns are common. Our argument is that if a rock from Mars or some other world shows this same pattern, this is strong evidence that life was involved.

View larger. | Artist’s concept of exoplanet K2-18b as a Hycean world with a global ocean and hydrogen atmosphere. Could there be life on K2-18b? New results from the Webb Space Telescope are tantalizing but not yet conclusive. And they’ve been met with skepticism from other scientists. Image via A. Smith/ N. Madhusudhan (University of Cambridge).

Truly exotic life?

This approach to the search for life also opens up the possibilities for types of life that we’ve never seen or even conceived of. But we could possibly identify it by the same kinds of patterns of energy that we see in life on Earth. That would be true whether it’s microscopic bugs or life on a scale not possible on our planet. Tikhonov mused:

What if on some distant planet, life operates on an entirely different scale? One could imagine a mile-long being floating in some distant atmosphere. The possibilities are vast, which is why it’s fun to think about.

As it happens, huge organisms floating in planetary atmospheres is not a new idea. Astronomer Carl Sagan and physicist Edwin Salpeter pondered the possibility of gasbags on Jupiter or other gas giant planets. These large free-floating creatures would spend their entire lives drifting around in deep, turbulent atmospheres. We don’t know if anything like that actually exists, but at Tikhonov said, it’s fun to think about!

Bottom line: To search for alien life – even exotic life beyond our imagination – a new study suggests looking for “patterns of energy” instead of just organic molecules.

Source: Energy-ordered resource stratification as an agnostic signature of life

Via Washington University in St. Louis

Read more: Life on K2-18b? Exciting new results met with skepticism

Read more: Do aliens exist? What scientists really think

The post Want to find alien life? Look for patterns of energy first appeared on EarthSky.

from EarthSky https://ift.tt/N7JVMfW

View larger/full image. | NASA’s Curiosity rover on Mars saw this little flower-like rock formation in 2022. It has a life-like quality about it, but it’s really just a small piece of rock sculpted by Martian winds. Now, a new theoretical study has explored the best ways to search for alien life. The study asks whether we will recognize life if and when we find it. And it suggests a novel way to search. Image via NASA/ JPL-Caltech/ MSSS.

Science matters. Wonder matters. You matter. Join our 2025 Donation Campaign today.

• Biosignatures are the big focus nowadays in the search for life on other worlds. Astronomers search for molecules – in the atmospheres of distant planets – indicating the presence of life.
• But would we recognize life-related molecules if we found them? What if, instead of looking for molecules, we looked for patterns of energy? For example, we might look for the conversion of high-energy compounds into low-energy compounds, a process shared by all life on Earth.
• A new study suggests that even exotic forms of life – ones that defy our imagination – might be discovered using this approach.

Seeking patterns of energy

The search for life elsewhere in the universe is a unique and broad challenge. Scientists think of exploring a previously habitable Mars or the potentially habitable oceans of Jupiter’s moon Europa or Saturn’s moon Enceladus. Or, in a way that’s only recently become possible via technological advances, they spend time with the James Webb Telescope or other telescopes analyzing the atmospheres of distant exoplanets, searching for biosignatures, that is, molecules in those planets’ atmospheres that would indicate the presence of life. But would alien life resemble life on Earth? Or might life on another world be unrecognizable?

Mikhail Tikhonov, an assistant professor of physics at Washington University in St. Louis, Missouri, is an expert on microbial communities. He said on April 10, 2025 – in an interview with his university – that, to find alien life, instead of seeking molecules known on Earth to be related to living organisms, we might try searching for life by looking for telltale patterns of energy.

What he means is this. Suppose we found something interesting in a Martian rock, or an unusual chemical signature in the atmosphere of a faraway world. Could we know for sure it was a life sign? As Tikhonov noted:

There could be life forms out there that defy our imagination.

He and his colleague Akshit Goyal, a scientist in India, suggest that patterns of energy are an alternative way, perhaps a more foolproof way, to seek life in the galaxy.

Tikhonov and Goyal published their peer-reviewed theoretical results in Nature Communications on March 28, 2025.

Life is life is life?

Tikhonov noted, for example, in the Washington University interview, that life on Earth is carbon-based. In other words, carbon is the fundamental building block of the complex molecules that make up all known life forms. But scientists and others sometimes speculate about silicon-based life. Silicon shares chemical properties with carbon. Like carbon, it can potentially support complex molecules, though with some drawbacks. Tikhonov said:

We don’t know anything about what alien life forms might look like or what they’re made of.

But there are two things everyone agrees on: Living things have to consume and transform energy, and they have to be able to replicate. That’s as close as we can get to a definition of life.

When looking for measurable biosignatures – or signatures of life on other worlds – we need to make additional assumptions. We are proposing that any living organism is extremely unlikely to be on its own. It will always be a part of an ecological community that is competing for resources.

In the search for life on Mars, for example, the focus is largely on finding organic molecules. But organic molecules, by themselves, are not proof of life. They can also form without life being involved at all. And would alien life even have the same molecules as life on Earth? Tikhonov said:

But more importantly, there is no reason to believe that an alien life form would have to be using the same molecules we do.

Mikhail Tikhonov is a co-author of the new theoretical study about alien life. Image via Washington University in St. Louis.

Patterns of energy

So, is there another way to search for alien life? Tikhonov and Goyal think so. Instead of looking for specific molecules by themselves, they recommend looking for patterns of energy among many molecules. What do they mean by that? Basically, these patterns of energy arise the process of breaking down high-energy compounds, such as glucose, into low-energy compounds, like carbon dioxide. It’s the process of that energy change that is a telltale marker of life. As Tikhonov explained:

Life is incentivized to break down high-energy compounds first. Organisms that consume more energy-rich resources will outcompete and displace others, leading to a particular kind of layering, with compounds arranged by decreasing energy content. It doesn’t matter what the organisms look like. As long as you have self-replication and ecological competition, we expect this pattern to form.

Layered structures can be generated by many processes, both living and non-living. But only life cares about energy in this way, so energy-ordered layering would be special. On Earth, such patterns are common. Our argument is that if a rock from Mars or some other world shows this same pattern, this is strong evidence that life was involved.

View larger. | Artist’s concept of exoplanet K2-18b as a Hycean world with a global ocean and hydrogen atmosphere. Could there be life on K2-18b? New results from the Webb Space Telescope are tantalizing but not yet conclusive. And they’ve been met with skepticism from other scientists. Image via A. Smith/ N. Madhusudhan (University of Cambridge).

Truly exotic life?

This approach to the search for life also opens up the possibilities for types of life that we’ve never seen or even conceived of. But we could possibly identify it by the same kinds of patterns of energy that we see in life on Earth. That would be true whether it’s microscopic bugs or life on a scale not possible on our planet. Tikhonov mused:

What if on some distant planet, life operates on an entirely different scale? One could imagine a mile-long being floating in some distant atmosphere. The possibilities are vast, which is why it’s fun to think about.

As it happens, huge organisms floating in planetary atmospheres is not a new idea. Astronomer Carl Sagan and physicist Edwin Salpeter pondered the possibility of gasbags on Jupiter or other gas giant planets. These large free-floating creatures would spend their entire lives drifting around in deep, turbulent atmospheres. We don’t know if anything like that actually exists, but at Tikhonov said, it’s fun to think about!

Bottom line: To search for alien life – even exotic life beyond our imagination – a new study suggests looking for “patterns of energy” instead of just organic molecules.

Source: Energy-ordered resource stratification as an agnostic signature of life

Via Washington University in St. Louis

Read more: Life on K2-18b? Exciting new results met with skepticism

Read more: Do aliens exist? What scientists really think

The post Want to find alien life? Look for patterns of energy first appeared on EarthSky.

from EarthSky https://ift.tt/N7JVMfW

Save the Frogs Day is today, Sunday, April 28

Held every April 28, Save the Frogs Day is a global conservation effort to slow the decline of amphibian populations and their habitats. The 2025 event is tomorrow. According to the US Geological Survey (USGS), the loss of amphibians is not due to a single cause, and solutions will require a range of responses. Image via savethefrogs.com.

We’ve never needed good science more than we do right now. Support EarthSky in 2025 and help us keep it going strong.

Save the frogs … save the humans?

Our froggy friends are in big trouble and need our help.

The Amphibian Survival Alliance pulls no punches in describing the desperate crisis:

Around half of all amphibian species are declining, and the proportion threatened with extinction is thought to be over 40%, making amphibians the most threatened vertebrate group. Once a sanctuary for over 8,000 species, we now live in a world that is increasingly unsafe for amphibians. A world that is unsafe for amphibians is unsafe for other species, not least humankind.

According to the U.S. Geological Survey (USGS), an “unabated” decline in frog populations – and amphibians in general – began in the U.S. in the 1960s and continues to today. Currently, the number of amphibians in the U.S. is falling at 3.79% annually.

Fixing a global problem requires a worldwide effort. So, this Monday, April 28, 2025, everyone can – and should – join in during the 17th annual Save the Frogs Day.

All hands on deck to save the amphibians

While the loss of such charismatic creatures is disheartening, the response doesn’t need to be. That’s why in 2008, Kerry Kriger founded the nonprofit Save the Frogs! foundation, sponsor of Save the Frogs Day.

Save The Frogs Day is the world’s largest day of amphibian education and conservation action. Our goal is to provide frog enthusiasts with educational materials, ideas and inspiration and empower them to educate their local communities about amphibians.

Find a 2025 event for April 28; there are opportunities around the world

The foundation’s key event is meant to be fun and solution-oriented. In fact, there have been thousands of past local happenings on Save the Frog Day in 58 different countries. For example, these have included parades, art exhibits, habitat restoration projects and even protests.

Save the Frogs Day has grown in popularity each year, probably because, in the words of late comedian Mitch Hedberg, “frogs are always cool.” And, as Hedberg noted, they inspire enthusiasm:

It’s always optimistic, like, “Hey, here comes that frog! All right! Maybe he will settle near me.”

A horned marsupial frog (Gastrotheca cornuta) clings to a reed in a wetland near El Cope, Panama, in 2002. Amphibians – and frogs in particular – are in sharp decline around the globe. The annual Save the Frogs Day held every April 28 (savethefrogs.com) is a global effort to raise awareness and encourage people to take action to protect threatened species and their habitats. Image via Andrew J. Crawford/ UC Berkeley (CC BY-SA-NC 3.0).

Reasons for Save the Frogs Day

Frogs and their cousins don’t get the credit they deserve. The froggy foundation says they make a genuine contribution to the quality of human existence.

Amphibians provide an array of ecosystem services, and knowledge of amphibians has led to numerous advances in human medicine. Plus frogs look and sound cool, and kids love them …

One of the “ecosystem services” frogs are famous for is eating bugs, especially flying insects. That means when amphibian populations bomb, their prey species, like mosquitoes, can boom.

A study published in September 2022 in the peer-reviewed journal Environmental Research Letters described the aftermath of mass amphibian die-offs due to a fungal infection in Central America. Loss of amphibians, researchers discovered, correlated directly with a rise in cases of deadly malaria.

This wave traveled from northwest to southeast across Costa Rica from the early 1980s to the mid-1990s and then continued eastward across Panama through the 2000s. After this rolling collapse of amphibian populations, both countries experienced large increases in malaria cases.

The fungus attacking amphibians is chytridiomycosis. And it’s spreading around the globe. Amphibiaweb described the fungal disease as the current greatest danger to amphibians:

The causes for recent amphibian declines are many, but an emerging disease called chytridiomycosis and global climate change are thought the be the biggest threats to amphibians. Chytridiomycosis is a disease caused by the fungal chytrid pathogen Batrachochytrium dendrobatidis (Bd). This pathogen is associated with the global loss of hundreds of species of amphibians and represents a spectacular loss of biodiversity, some say the worst in recorded history.

Bd has spread to all inhabited continents, likely due to human-caused contamination occurring in the global frog trade.

Find a 2025 event for April 28; there are opportunities around the world

Amphibians are a canary in a coal mine

While the USGS agrees disease and climate change are leading drivers of the decline in amphibian populations, other factors are also working against our slimy but cute little friends. Climate change plays the most significant role in the southern U.S. and West Coast. But elsewhere loss of habitat is driving the wave of extinction. Also, pesticides can be particularly deadly to amphibians. As the USGS said:

Amphibians, unlike people, breathe at least partly through their skin, which is constantly exposed to everything in their environment. Consequently, their bodies are much more sensitive to environmental factors such as disease, pollution, toxic chemicals, ultraviolet radiation and habitat destruction. The worldwide occurrences of amphibian declines and deformities could be an early warning that some of our ecosystems, even seemingly pristine ones, are seriously out of balance.

The USGS considers the decline of amphibian species to be damaging to ecosystems and biodiversity. To track the unfolding and troubling story of the amphibian die-off, and to provide information and guidance aimed at improving the situation, the USGS has established the Amphibian Research and Monitoring Initiative.

Check out Amphibiaweb’s resource page for more information on amphibians and how to help them survive.

Bottom line: Save the Frogs Day – a yearly, global amphibian conservation effort – is tomorrow, Monday, April 28, 2025. Amphibian health is an important marker of overall ecosystem quality.

Find a 2025 event for April 28; there are opportunities around the world

The post Save the Frogs Day is today, Sunday, April 28 first appeared on EarthSky.

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Held every April 28, Save the Frogs Day is a global conservation effort to slow the decline of amphibian populations and their habitats. The 2025 event is tomorrow. According to the US Geological Survey (USGS), the loss of amphibians is not due to a single cause, and solutions will require a range of responses. Image via savethefrogs.com.

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Save the frogs … save the humans?

Our froggy friends are in big trouble and need our help.

The Amphibian Survival Alliance pulls no punches in describing the desperate crisis:

Around half of all amphibian species are declining, and the proportion threatened with extinction is thought to be over 40%, making amphibians the most threatened vertebrate group. Once a sanctuary for over 8,000 species, we now live in a world that is increasingly unsafe for amphibians. A world that is unsafe for amphibians is unsafe for other species, not least humankind.

According to the U.S. Geological Survey (USGS), an “unabated” decline in frog populations – and amphibians in general – began in the U.S. in the 1960s and continues to today. Currently, the number of amphibians in the U.S. is falling at 3.79% annually.

Fixing a global problem requires a worldwide effort. So, this Monday, April 28, 2025, everyone can – and should – join in during the 17th annual Save the Frogs Day.

All hands on deck to save the amphibians

While the loss of such charismatic creatures is disheartening, the response doesn’t need to be. That’s why in 2008, Kerry Kriger founded the nonprofit Save the Frogs! foundation, sponsor of Save the Frogs Day.

Save The Frogs Day is the world’s largest day of amphibian education and conservation action. Our goal is to provide frog enthusiasts with educational materials, ideas and inspiration and empower them to educate their local communities about amphibians.

Find a 2025 event for April 28; there are opportunities around the world

The foundation’s key event is meant to be fun and solution-oriented. In fact, there have been thousands of past local happenings on Save the Frog Day in 58 different countries. For example, these have included parades, art exhibits, habitat restoration projects and even protests.

Save the Frogs Day has grown in popularity each year, probably because, in the words of late comedian Mitch Hedberg, “frogs are always cool.” And, as Hedberg noted, they inspire enthusiasm:

It’s always optimistic, like, “Hey, here comes that frog! All right! Maybe he will settle near me.”

A horned marsupial frog (Gastrotheca cornuta) clings to a reed in a wetland near El Cope, Panama, in 2002. Amphibians – and frogs in particular – are in sharp decline around the globe. The annual Save the Frogs Day held every April 28 (savethefrogs.com) is a global effort to raise awareness and encourage people to take action to protect threatened species and their habitats. Image via Andrew J. Crawford/ UC Berkeley (CC BY-SA-NC 3.0).

Reasons for Save the Frogs Day

Frogs and their cousins don’t get the credit they deserve. The froggy foundation says they make a genuine contribution to the quality of human existence.

Amphibians provide an array of ecosystem services, and knowledge of amphibians has led to numerous advances in human medicine. Plus frogs look and sound cool, and kids love them …

One of the “ecosystem services” frogs are famous for is eating bugs, especially flying insects. That means when amphibian populations bomb, their prey species, like mosquitoes, can boom.

A study published in September 2022 in the peer-reviewed journal Environmental Research Letters described the aftermath of mass amphibian die-offs due to a fungal infection in Central America. Loss of amphibians, researchers discovered, correlated directly with a rise in cases of deadly malaria.

This wave traveled from northwest to southeast across Costa Rica from the early 1980s to the mid-1990s and then continued eastward across Panama through the 2000s. After this rolling collapse of amphibian populations, both countries experienced large increases in malaria cases.

The fungus attacking amphibians is chytridiomycosis. And it’s spreading around the globe. Amphibiaweb described the fungal disease as the current greatest danger to amphibians:

The causes for recent amphibian declines are many, but an emerging disease called chytridiomycosis and global climate change are thought the be the biggest threats to amphibians. Chytridiomycosis is a disease caused by the fungal chytrid pathogen Batrachochytrium dendrobatidis (Bd). This pathogen is associated with the global loss of hundreds of species of amphibians and represents a spectacular loss of biodiversity, some say the worst in recorded history.

Bd has spread to all inhabited continents, likely due to human-caused contamination occurring in the global frog trade.

Find a 2025 event for April 28; there are opportunities around the world

Amphibians are a canary in a coal mine

While the USGS agrees disease and climate change are leading drivers of the decline in amphibian populations, other factors are also working against our slimy but cute little friends. Climate change plays the most significant role in the southern U.S. and West Coast. But elsewhere loss of habitat is driving the wave of extinction. Also, pesticides can be particularly deadly to amphibians. As the USGS said:

Amphibians, unlike people, breathe at least partly through their skin, which is constantly exposed to everything in their environment. Consequently, their bodies are much more sensitive to environmental factors such as disease, pollution, toxic chemicals, ultraviolet radiation and habitat destruction. The worldwide occurrences of amphibian declines and deformities could be an early warning that some of our ecosystems, even seemingly pristine ones, are seriously out of balance.

The USGS considers the decline of amphibian species to be damaging to ecosystems and biodiversity. To track the unfolding and troubling story of the amphibian die-off, and to provide information and guidance aimed at improving the situation, the USGS has established the Amphibian Research and Monitoring Initiative.

Check out Amphibiaweb’s resource page for more information on amphibians and how to help them survive.

Bottom line: Save the Frogs Day – a yearly, global amphibian conservation effort – is tomorrow, Monday, April 28, 2025. Amphibian health is an important marker of overall ecosystem quality.

Find a 2025 event for April 28; there are opportunities around the world

The post Save the Frogs Day is today, Sunday, April 28 first appeared on EarthSky.

from EarthSky https://ift.tt/w39Sfro

Tides, and the pull of the moon and sun

View at EarthSky Community Photos. | Cecille Kennedy captured this in Oregon on December 14, 2024. Cecille wrote: “It is the time of king tides at the Oregon coast. The tides get higher than other times of the year when the sun, moon and Earth are in alignment. This alignment which increases their gravitational pull affects the tides. Thus the king tides occur. Here is an image of a roaring wave crashing on a rock that protrudes into the ocean.” Thank you, Cecille!

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Expect supermoon tides today or tomorrow

The new moon today (April 27, 2025) is the closest new moon of the year. And – just over three hours before the moon will reach the crest of its new phase – the moon also reached perigee, its closest point to Earth. So, today’s moon will be a new supermoon. And even though you can’t see a new supermoon – like you can a full supermoon – you can see its effect on the tides. Also, especially if you live along a coast, you might know that especially high tides – sometimes called perigean tides, or king tides or even supermoon tides – tend to fall on the day or so after a new or full moon.

Supermoons in 2025

April’s new supermoon is the closest of the five new supermoons in 2025. We had new supermoons in February and March, and we will have two more in May and June.

And what about full supermoons? In 2025-2026, we’ll have four full supermoons in October, November, December and January. The November full supermoon will be the closest full moon in 2025.

Around each new moon and full moon – when the sun, Earth, and moon are located more or less on a line in space – the range between high and low tides is greatest. These are the spring tides. Image via NOAA.

What are spring tides?

In most places, but not everywhere, there are two high tides and two low tides a day. The difference in height between high and low tides varies, as the moon waxes and wanes from new to full and back to new again. The moon and sun are primarily responsible for the rising and falling of ocean tides. However, for any particular place on Earth’s surface, the height of the tides and their fluctuation in time also depend on the shape of your specific beach and the angle of the seabed leading up to your beach, plus your larger coastline and the prevailing ocean currents and winds.

Around each new moon and full moon, the sun, Earth, and moon lie more or less along a line in space. Then the pull on the tides increases, because the gravity of the sun reinforces the moon’s gravity. In fact, the height of the average solar tide is about 50% of the average lunar tide.

Thus, at new moon or full moon, the tide’s range is at its maximum. This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season. This is spring in the sense of jump, burst forth, rise.

So, spring tides bring the most extreme high and low tides every month. And they always happen – every month – around full and new moon.

Why?

When the new moon or full moon closely aligns with perigee – the closest point to Earth in the moon’s orbit – then we have a supermoon and extra-large spring tides.

In 2018, the January 1-2 full moon closely aligned with perigee to bring forth especially high tides. As it happened, on the day after the January 1-2 supermoon, Storm Eleanor hit Europe with winds of up to 100 mph (160 km/h). The wind and extra-high tides caused flooding, hampered travel, injured and killed people and left tens of thousands of homes without power across the U.K., Ireland and other parts of Europe. No doubt the extra-high tides contributed to the severity of the storm. Read more: High tides and winter storms (2018).

Why are the tides at their strongest around supermoons? It’s simply because the moon is at its closest to Earth, and thus the Earth’s oceans are feeling the pull of the moon’s gravity most powerfully.

Should you expect these highest tides on the exact day of a supermoon? Probably not. The highest tides tend to follow the supermoon (or any new or full moon) by a day or two.

What about flooding?

Do the most extreme high tides – those bringing floods – always occur at supermoons? Not necessarily. It’s when a spring tide coincides with a time of heavy winds and rain – flooding due to a weather extreme – that the most extreme flooding occurs.

Spring tides and neap tides coincide with particular phases of the moon. Around each new moon and full moon – when the sun, Earth, and moon align in space – the range between high and low tides is greatest. These are the spring tides. Around each first quarter moon and last quarter moon – when the sun and moon are at a right angle to Earth – the range between high and low tides is the least. These are the neap tides. Image via NOAA.

View at EarthSky Community Photos. | Christy Mandeville of Indian Shores, Florida, captured this image of ocean waves surging onto a beach on June 4, 2023. Thank you, Christy!

What are neap tides?

There’s about a seven-day interval between spring tides and neap tides, when the tide’s range is at its minimum. Neap tides occur halfway between each new and full moon – at the first quarter and last quarter moon phase – when the sun and moon are at right angles as seen from Earth. Then the sun’s gravity is working against the gravity of the moon, as the moon pulls on the sea. Neap tides happen approximately twice a month, once around first quarter moon and once around last quarter moon.

Why two high and two low each day?

If the moon is primarily responsible for the tides, why are there two high tides and two low tides each day in most places? It seems as if there should just be one. If you picture the part of Earth closest to the moon, it’s easy to see that the ocean is drawn toward the moon. That’s because gravity depends in part on how close two objects are.

But then why – on the opposite side of Earth – is there another tidal bulge, in the direction opposite the moon? It seems counterintuitive, until you realize that this second bulge happens at the part of Earth where the moon’s gravity is pulling the least.

Earth spins once every 24 hours. So, a given location on Earth will pass “through” both bulges of water each day. Of course, the bulges don’t stay fixed in time. They move at the slow rate of about 13.1 degrees per day. That’s the same rate as the monthly motion of the moon relative to the stars. Other factors, including the shape of coastlines, also influence the time of the tides, which is why people who live near coastlines like to have a good tide almanac.

Bottom line: The sun, the moon, the shape of a beach, the angle of the seabed leading up to land, and the prevailing ocean currents and winds all affect the height of the tides. In 2025, expect higher-than-usual tides for a few days following the new and full supermoons.

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The post Tides, and the pull of the moon and sun first appeared on EarthSky.

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View at EarthSky Community Photos. | Cecille Kennedy captured this in Oregon on December 14, 2024. Cecille wrote: “It is the time of king tides at the Oregon coast. The tides get higher than other times of the year when the sun, moon and Earth are in alignment. This alignment which increases their gravitational pull affects the tides. Thus the king tides occur. Here is an image of a roaring wave crashing on a rock that protrudes into the ocean.” Thank you, Cecille!

We’re not powered by billionaires. We’re powered by you. Support EarthSky’s 2025 Donation Campaign and help keep science accessible.

Expect supermoon tides today or tomorrow

The new moon today (April 27, 2025) is the closest new moon of the year. And – just over three hours before the moon will reach the crest of its new phase – the moon also reached perigee, its closest point to Earth. So, today’s moon will be a new supermoon. And even though you can’t see a new supermoon – like you can a full supermoon – you can see its effect on the tides. Also, especially if you live along a coast, you might know that especially high tides – sometimes called perigean tides, or king tides or even supermoon tides – tend to fall on the day or so after a new or full moon.

Supermoons in 2025

April’s new supermoon is the closest of the five new supermoons in 2025. We had new supermoons in February and March, and we will have two more in May and June.

And what about full supermoons? In 2025-2026, we’ll have four full supermoons in October, November, December and January. The November full supermoon will be the closest full moon in 2025.

Around each new moon and full moon – when the sun, Earth, and moon are located more or less on a line in space – the range between high and low tides is greatest. These are the spring tides. Image via NOAA.

What are spring tides?

In most places, but not everywhere, there are two high tides and two low tides a day. The difference in height between high and low tides varies, as the moon waxes and wanes from new to full and back to new again. The moon and sun are primarily responsible for the rising and falling of ocean tides. However, for any particular place on Earth’s surface, the height of the tides and their fluctuation in time also depend on the shape of your specific beach and the angle of the seabed leading up to your beach, plus your larger coastline and the prevailing ocean currents and winds.

Around each new moon and full moon, the sun, Earth, and moon lie more or less along a line in space. Then the pull on the tides increases, because the gravity of the sun reinforces the moon’s gravity. In fact, the height of the average solar tide is about 50% of the average lunar tide.

Thus, at new moon or full moon, the tide’s range is at its maximum. This is the spring tide: the highest (and lowest) tide. Spring tides are not named for the season. This is spring in the sense of jump, burst forth, rise.

So, spring tides bring the most extreme high and low tides every month. And they always happen – every month – around full and new moon.

Why?

When the new moon or full moon closely aligns with perigee – the closest point to Earth in the moon’s orbit – then we have a supermoon and extra-large spring tides.

In 2018, the January 1-2 full moon closely aligned with perigee to bring forth especially high tides. As it happened, on the day after the January 1-2 supermoon, Storm Eleanor hit Europe with winds of up to 100 mph (160 km/h). The wind and extra-high tides caused flooding, hampered travel, injured and killed people and left tens of thousands of homes without power across the U.K., Ireland and other parts of Europe. No doubt the extra-high tides contributed to the severity of the storm. Read more: High tides and winter storms (2018).

Why are the tides at their strongest around supermoons? It’s simply because the moon is at its closest to Earth, and thus the Earth’s oceans are feeling the pull of the moon’s gravity most powerfully.

Should you expect these highest tides on the exact day of a supermoon? Probably not. The highest tides tend to follow the supermoon (or any new or full moon) by a day or two.

What about flooding?

Do the most extreme high tides – those bringing floods – always occur at supermoons? Not necessarily. It’s when a spring tide coincides with a time of heavy winds and rain – flooding due to a weather extreme – that the most extreme flooding occurs.

Spring tides and neap tides coincide with particular phases of the moon. Around each new moon and full moon – when the sun, Earth, and moon align in space – the range between high and low tides is greatest. These are the spring tides. Around each first quarter moon and last quarter moon – when the sun and moon are at a right angle to Earth – the range between high and low tides is the least. These are the neap tides. Image via NOAA.

View at EarthSky Community Photos. | Christy Mandeville of Indian Shores, Florida, captured this image of ocean waves surging onto a beach on June 4, 2023. Thank you, Christy!

What are neap tides?

There’s about a seven-day interval between spring tides and neap tides, when the tide’s range is at its minimum. Neap tides occur halfway between each new and full moon – at the first quarter and last quarter moon phase – when the sun and moon are at right angles as seen from Earth. Then the sun’s gravity is working against the gravity of the moon, as the moon pulls on the sea. Neap tides happen approximately twice a month, once around first quarter moon and once around last quarter moon.

Why two high and two low each day?

If the moon is primarily responsible for the tides, why are there two high tides and two low tides each day in most places? It seems as if there should just be one. If you picture the part of Earth closest to the moon, it’s easy to see that the ocean is drawn toward the moon. That’s because gravity depends in part on how close two objects are.

But then why – on the opposite side of Earth – is there another tidal bulge, in the direction opposite the moon? It seems counterintuitive, until you realize that this second bulge happens at the part of Earth where the moon’s gravity is pulling the least.

Earth spins once every 24 hours. So, a given location on Earth will pass “through” both bulges of water each day. Of course, the bulges don’t stay fixed in time. They move at the slow rate of about 13.1 degrees per day. That’s the same rate as the monthly motion of the moon relative to the stars. Other factors, including the shape of coastlines, also influence the time of the tides, which is why people who live near coastlines like to have a good tide almanac.

Bottom line: The sun, the moon, the shape of a beach, the angle of the seabed leading up to land, and the prevailing ocean currents and winds all affect the height of the tides. In 2025, expect higher-than-usual tides for a few days following the new and full supermoons.

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

The post Tides, and the pull of the moon and sun first appeared on EarthSky.

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Old Soviet spacecraft to fall to Earth in early May 2025

Artist’s illustration showing a spacecraft reentering Earth’s atmosphere. An old Soviet spacecraft – Kosmos 482 – that has been circling Earth for 53 years is set to finally reenter our atmosphere between May 8 and 11, 2025. Image via David Ducross/ ESA.

Soviet spacecraft to fall to Earth soon

An unusual object is about to re-enter Earth’s atmosphere. The heat-resistant Soviet spacecraft Kosmos 482 launched on March 31, 1972, bound for Venus. After a successful launch to a temporary orbit around Earth, a problem with a timer cut an engine burn prematurely. So the spacecraft was unable to leave our planet’s orbit. It’s been circling Earth for 53 years and will reenter the atmosphere around May 8 to 11, 2025.

As we get closer to the date and continue to monitor its orbital height, we’ll be able to estimate a more precise reentry date.

The re-entry date might be sooner or later, depending on the sun’s activity. Why? Because when the sun gets more active, our planet’s upper atmosphere gets hotter and expands. That, in turn, causes more atmospheric drag on low-orbiting objects, slowing the orbital speed and thus causing the reentry to occur sooner.

Where will it re-enter?

It’s extremely difficult to determine over which area the uncontrolled reentry will occur. But the current orbit indicates it will be anywhere between latitude 52° N and 52° S. However, our planet is mostly ocean-covered. And that means the probability that the reentry will be over water is high.

Is there any risk?

There is a small risk with the spacecraft reentry. Although the odds that it occurs over land or a populated area are small, the inconvenient detail with Kosmos 482 is that it was a probe similar to the Venera mission landers. That is, they were built to withstand acceleration and the high pressures and extreme heat of Venus. So most of the lander, even if not intact, may still reach our planet’s surface.

The 1,091-pound (495-kg) landing module is about 3.2 feet (1 meter) across. And, according to satellite expert Marco Langbroek, impact speed might be around 150 miles (242 km) per hour after atmospheric drag deceleration.

This is a replica of the Kosmos 482 Soviet spacecraft. Image via Wikimedia.

Will it be visible to the eye before reentering?

As it continues to orbit Earth, you might be able to see Kosmos 482 around dusk and dawn from some areas, just as any moving dim satellite is visible from dark skies. It may become slightly brighter as we get close to the reentry date. You can enter your observing location on Heavens-Above.com and select “Satellite Database,” then select “1972” in year of launch, press Update, select the last object in the list (Cosmos 482 Debris / 1972-023E), then select “Passes.” If there is a visible pass, select it to see where in the sky it will appear, and when.

Will the Soviet spacecraft be visible during reentry?

In the rare case that reentry occurs over your area, the object should look similar to a very bright and slow meteor, probably showing some fragmentation.

As we get closer to the reentry of this unusual orbiting object, we will keep you updated.

Bottom line: An old Soviet spacecraft that has been circling Earth for 53 years is set to finally reenter our atmosphere between May 8 and 11, 2025.

Read more: Space vehicle reentries shed exotic metal particles to Earth’s atmosphere

The post Old Soviet spacecraft to fall to Earth in early May 2025 first appeared on EarthSky.

from EarthSky https://ift.tt/vOc0tFy

Artist’s illustration showing a spacecraft reentering Earth’s atmosphere. An old Soviet spacecraft – Kosmos 482 – that has been circling Earth for 53 years is set to finally reenter our atmosphere between May 8 and 11, 2025. Image via David Ducross/ ESA.

Soviet spacecraft to fall to Earth soon

An unusual object is about to re-enter Earth’s atmosphere. The heat-resistant Soviet spacecraft Kosmos 482 launched on March 31, 1972, bound for Venus. After a successful launch to a temporary orbit around Earth, a problem with a timer cut an engine burn prematurely. So the spacecraft was unable to leave our planet’s orbit. It’s been circling Earth for 53 years and will reenter the atmosphere around May 8 to 11, 2025.

As we get closer to the date and continue to monitor its orbital height, we’ll be able to estimate a more precise reentry date.

The re-entry date might be sooner or later, depending on the sun’s activity. Why? Because when the sun gets more active, our planet’s upper atmosphere gets hotter and expands. That, in turn, causes more atmospheric drag on low-orbiting objects, slowing the orbital speed and thus causing the reentry to occur sooner.

Where will it re-enter?

It’s extremely difficult to determine over which area the uncontrolled reentry will occur. But the current orbit indicates it will be anywhere between latitude 52° N and 52° S. However, our planet is mostly ocean-covered. And that means the probability that the reentry will be over water is high.

Is there any risk?

There is a small risk with the spacecraft reentry. Although the odds that it occurs over land or a populated area are small, the inconvenient detail with Kosmos 482 is that it was a probe similar to the Venera mission landers. That is, they were built to withstand acceleration and the high pressures and extreme heat of Venus. So most of the lander, even if not intact, may still reach our planet’s surface.

The 1,091-pound (495-kg) landing module is about 3.2 feet (1 meter) across. And, according to satellite expert Marco Langbroek, impact speed might be around 150 miles (242 km) per hour after atmospheric drag deceleration.

This is a replica of the Kosmos 482 Soviet spacecraft. Image via Wikimedia.

Will it be visible to the eye before reentering?

As it continues to orbit Earth, you might be able to see Kosmos 482 around dusk and dawn from some areas, just as any moving dim satellite is visible from dark skies. It may become slightly brighter as we get close to the reentry date. You can enter your observing location on Heavens-Above.com and select “Satellite Database,” then select “1972” in year of launch, press Update, select the last object in the list (Cosmos 482 Debris / 1972-023E), then select “Passes.” If there is a visible pass, select it to see where in the sky it will appear, and when.

Will the Soviet spacecraft be visible during reentry?

In the rare case that reentry occurs over your area, the object should look similar to a very bright and slow meteor, probably showing some fragmentation.

As we get closer to the reentry of this unusual orbiting object, we will keep you updated.

Bottom line: An old Soviet spacecraft that has been circling Earth for 53 years is set to finally reenter our atmosphere between May 8 and 11, 2025.

Read more: Space vehicle reentries shed exotic metal particles to Earth’s atmosphere

The post Old Soviet spacecraft to fall to Earth in early May 2025 first appeared on EarthSky.

from EarthSky https://ift.tt/vOc0tFy

Solar wind might make water on the moon, study says

Data visualization of the sun as seen from Apollo 16’s lunar landing site. A new experiment, using moon dust collected on the Apollo 17 mission, has found evidence that the sun’s solar wind could produce water on the moon’s surface. Image via NASA/ Ernie Wright.

• The solar wind is a stream of charged particles constantly flowing out from the sun into the solar system.
• Scientists have long thought these particles could trigger the production of water molecules when they hit our moon’s surface.
• Now a NASA experiment has recreated this reaction on Earth, using lunar samples from the Apollo 17 mission.

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The sun could be making water on the moon

In addition to its life-giving radiation, the sun is constantly firing out a stream of charged particles we call the solar wind. This powerful stream has impacts across the solar system. It triggers beautiful auroras on Earth and other planets and even stripped away Mars’ atmosphere. On April 15, 2025, NASA said that, according to a new study, it may also be producing water on our moon.

We know the moon’s surface hosts water molecules, mostly frozen in craters at the lunar poles. And scientists have theorized for decades that a reaction between solar wind and lunar soil could trigger the production of this water. Now, having performed a new experiment on moon dust from the Apollo 17 mission, NASA researchers have found strong evidence that their suspicions were correct.

The researchers published the peer-reviewed study on March 17, 2025, in the Journal of Geophysical Research: Planets.

The powerful solar wind

At any given moment, the sun is blasting out solar wind in all directions. Traveling at about one million miles per hour (1.6 million km/h), this wind is mostly made up of protons and electrons in a state known as plasma.

These charged particles generally don’t reach Earth’s surface, because our planet’s atmosphere and magnetic field deflect them. But we can see their effects when a surge in the solar wind unsettles our magnetic field enough to trigger beautiful auroras.

Our moon, however, doesn’t have the same protection. With no real atmosphere or magnetic field to speak of, the solar wind is constantly bombarding its surface. But how could this create water?

Computer-processed data of the solar wind from NASA’s STEREO spacecraft. Imagery via NASA/ SwRI/ Craig DeForest.

The theory

Protons, which make up much of the solar wind, are simply hydrogen atoms without their electrons. And simulations have shown that when a proton hits the moon’s surface, it should collide and combine with an electron, forming a hydrogen atom.

When you’ve got hydrogen, all that’s left to make H2O is the O: oxygen. And the moon has that in abundance. The moon’s rocky “soil”, known as regolith, is made up of around 45% oxygen, bound up in minerals like silica.

So scientists have theorized since the 1960s that solar wind hitting the moon’s surface should create hydrogen, which could then bond with oxygen to form hydroxyl (OH) and, in turn, water.

Solar wind, or something else?

Sure enough, scientists have detected signs of hydroxyl and water in the upper few millimeters of the lunar surface. They can see these molecules through spectroscopy, identifying their chemical fingerprints in the way light reflects off the lunar soil.

So, is the solar wind the reason the molecules are there? Some scientists, for instance, have thought that micrometeorites might provide enough heat to trigger a water-producing reaction.

But the new study confirmed a key clue: The amount of water detected on the moon’s surface changes throughout the day. It drops as the moon’s surface heats up, seemingly because the excited water molecules are escaping to space. And the signal jumps up again when the surface cools at night. This means these molecules must have a source of constant replenishment. And that makes the ever-present solar wind a likely suspect. But this process still needed testing.

NASA astronaut Harrison Schmitt collects a soil sample during the Apollo 17 mission. Image via NASA.

Testing 50-year-old moon dust

To test the theory, the scientists used two samples of lunar material collected by Apollo 17 astronauts in 1972, the last time humans set foot on the moon. The test involved using a particle accelerator to subject the material to an equivalent of the solar wind. While scientists have performed experiments like this before, this time there was one key difference. The scientists built an airless container to hold the entire experiment, allowing them to avoid exposing the lunar sample to contamination from water in the air.

Jason McLain, co-author of the study, explained:

It took a long time and many iterations to design the apparatus components and get them all to fit inside, but it was worth it, because once we eliminated all possible sources of contamination, we learned that this decades-old idea about the solar wind turns out to be true.

Indeed, having subjected the samples to the equivalent of 80,000 years of solar wind, they detected new, strong signals of both hydroxyl and water. While not definitive proof, it’s a very strong indication that the solar wind really does make water on the moon.

Bottom line: A new NASA study has found strong evidence that the solar wind constantly fired out by the sun produces water on our moon.

Source: Hydroxylation and Hydrogen Diffusion in Lunar Samples: Spectral Measurements During Proton Irradiation

Via NASA

Read more: Heatwave on Jupiter from strong solar wind amazes scientists

Read more: There may be less water ice on the moon than we thought

The post Solar wind might make water on the moon, study says first appeared on EarthSky.

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Data visualization of the sun as seen from Apollo 16’s lunar landing site. A new experiment, using moon dust collected on the Apollo 17 mission, has found evidence that the sun’s solar wind could produce water on the moon’s surface. Image via NASA/ Ernie Wright.

• The solar wind is a stream of charged particles constantly flowing out from the sun into the solar system.
• Scientists have long thought these particles could trigger the production of water molecules when they hit our moon’s surface.
• Now a NASA experiment has recreated this reaction on Earth, using lunar samples from the Apollo 17 mission.

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The sun could be making water on the moon

In addition to its life-giving radiation, the sun is constantly firing out a stream of charged particles we call the solar wind. This powerful stream has impacts across the solar system. It triggers beautiful auroras on Earth and other planets and even stripped away Mars’ atmosphere. On April 15, 2025, NASA said that, according to a new study, it may also be producing water on our moon.

We know the moon’s surface hosts water molecules, mostly frozen in craters at the lunar poles. And scientists have theorized for decades that a reaction between solar wind and lunar soil could trigger the production of this water. Now, having performed a new experiment on moon dust from the Apollo 17 mission, NASA researchers have found strong evidence that their suspicions were correct.

The researchers published the peer-reviewed study on March 17, 2025, in the Journal of Geophysical Research: Planets.

The powerful solar wind

At any given moment, the sun is blasting out solar wind in all directions. Traveling at about one million miles per hour (1.6 million km/h), this wind is mostly made up of protons and electrons in a state known as plasma.

These charged particles generally don’t reach Earth’s surface, because our planet’s atmosphere and magnetic field deflect them. But we can see their effects when a surge in the solar wind unsettles our magnetic field enough to trigger beautiful auroras.

Our moon, however, doesn’t have the same protection. With no real atmosphere or magnetic field to speak of, the solar wind is constantly bombarding its surface. But how could this create water?

Computer-processed data of the solar wind from NASA’s STEREO spacecraft. Imagery via NASA/ SwRI/ Craig DeForest.

The theory

Protons, which make up much of the solar wind, are simply hydrogen atoms without their electrons. And simulations have shown that when a proton hits the moon’s surface, it should collide and combine with an electron, forming a hydrogen atom.

When you’ve got hydrogen, all that’s left to make H2O is the O: oxygen. And the moon has that in abundance. The moon’s rocky “soil”, known as regolith, is made up of around 45% oxygen, bound up in minerals like silica.

So scientists have theorized since the 1960s that solar wind hitting the moon’s surface should create hydrogen, which could then bond with oxygen to form hydroxyl (OH) and, in turn, water.

Solar wind, or something else?

Sure enough, scientists have detected signs of hydroxyl and water in the upper few millimeters of the lunar surface. They can see these molecules through spectroscopy, identifying their chemical fingerprints in the way light reflects off the lunar soil.

So, is the solar wind the reason the molecules are there? Some scientists, for instance, have thought that micrometeorites might provide enough heat to trigger a water-producing reaction.

But the new study confirmed a key clue: The amount of water detected on the moon’s surface changes throughout the day. It drops as the moon’s surface heats up, seemingly because the excited water molecules are escaping to space. And the signal jumps up again when the surface cools at night. This means these molecules must have a source of constant replenishment. And that makes the ever-present solar wind a likely suspect. But this process still needed testing.

NASA astronaut Harrison Schmitt collects a soil sample during the Apollo 17 mission. Image via NASA.

Testing 50-year-old moon dust

To test the theory, the scientists used two samples of lunar material collected by Apollo 17 astronauts in 1972, the last time humans set foot on the moon. The test involved using a particle accelerator to subject the material to an equivalent of the solar wind. While scientists have performed experiments like this before, this time there was one key difference. The scientists built an airless container to hold the entire experiment, allowing them to avoid exposing the lunar sample to contamination from water in the air.

Jason McLain, co-author of the study, explained:

It took a long time and many iterations to design the apparatus components and get them all to fit inside, but it was worth it, because once we eliminated all possible sources of contamination, we learned that this decades-old idea about the solar wind turns out to be true.

Indeed, having subjected the samples to the equivalent of 80,000 years of solar wind, they detected new, strong signals of both hydroxyl and water. While not definitive proof, it’s a very strong indication that the solar wind really does make water on the moon.

Bottom line: A new NASA study has found strong evidence that the solar wind constantly fired out by the sun produces water on our moon.

Source: Hydroxylation and Hydrogen Diffusion in Lunar Samples: Spectral Measurements During Proton Irradiation

Via NASA

Read more: Heatwave on Jupiter from strong solar wind amazes scientists

Read more: There may be less water ice on the moon than we thought

The post Solar wind might make water on the moon, study says first appeared on EarthSky.

from EarthSky https://ift.tt/691iFbo