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If we find life beyond Earth, how will nations respond?

Life beyond Earth: Closeup, microscopic view of bumpy structures on a rock surface, one looking like a worm.
A super-closeup view of Mars meteorite ALH84001, found in Antarctica. What is that famous sub-micron-scale wormlike structure? If we ever do confirm life beyond Earth, how might the worlds’ nations respond? Experts think there are 3 possibilities. Image via NASA/ Wikimedia Commons.
  • Finding microbial life beyond Earth would be more than a scientific breakthrough. It has the potential to change how humanity thinks about itself.
  • Experts see three possible responses: nations could cooperate on research and regulation, or they could compete for scientific and economic advantages, or they could isolate themselves because of biosecurity concerns.
  • Policymakers can prepare now by using scenario planning to consider these possibilities, because the discovery of extraterrestrial life has the potential to bring both unprecedented cooperation and new forms of rivalry.

By Margaret E. Kosal, Georgia Institute of Technology; Dayana Alagirova, Georgia Institute of Technology, and Karryl Kim Sagun Trajano, Nanyang Technological University

If we find life beyond Earth, how will nations respond?

Microbes from space have fueled the plots of science fiction mainstays like Project Hail Mary and The Andromeda Strain. But with more space missions launching each year, finding extraterrestrial life in a microbial form is becoming more plausible. What will the response be back here on Earth if – or when – scientists discover extraterrestrial microbes? Will the international policy and security communities be prepared for the fallout?

When you hear about extraterrestrial life, your mind may go to intelligent life, like the kind present in a lot of Hollywood science fiction. But even the confirmation of microbial life that originated somewhere other than on Earth – which is much more likely – would be a paradigm-shifting event. Thinking about what these consequences might look like early on can help nations and the international community prepare.

Oblong tan and reddish irregular, textured rock.
This is the famous Martian meteorite ALH84001. Found in Antarctica, scientists for a time thought the meteorite from Mars showed evidence of life. Image via NASA/ Lunar and Planetary Institute.

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

Preparing for the possibility of life beyond Earth

Our team is interested in this question. We’re made up of a full professor of international affairs, who earned a Ph.D. in chemistry, and whose expertise is on how emerging science and technologies could affect global conflict and cooperation, as well as an emerging scholar in space policy and security and an expert on social and political implications of frontier technologies, such as AI, space, quantum and energy sources.

Multiple Mars landers have identified large amounts of frozen and liquid water, essential for life, on the red planet. Samples retrieved by Japan’s Hayabusa2 spacecraft from a near-Earth asteroid revealed the presence of uracil, part of RNA, which is a building block of life. Uncrewed space probes like NASA’s Europa Clipper and the European Space Agency’s Jupiter Icy Moons Explorer are on their way to conduct detailed reconnaissance of the planet’s moons and to investigate whether they have conditions suitable for life.

Along with data from the James Webb Space Telescope and future missions targeting Saturn’s icy moon Enceladus, the likelihood of discovering extraterrestrial microbial life has increased substantially.

Scientists are searching for life in space using what they know about life on Earth. But what will happen if or when they find something?

A governance challenge

The discovery of microbial life would expose significant gaps in international governance related to space.

While there are some existing international agreements, including the Outer Space Treaty, that provide space law guidelines, these are ill-equipped to address the complexities posed by extraterrestrial biology.

The Outer Space Treaty, established in 1967, dictates that countries should use outer space peacefully. It also states that no single nation may claim ownership or exert sovereignty over parts of outer space or celestial bodies such as the moon.

However, it doesn’t have much to say about who can own extraterrestrial organisms or what to do about biosecurity risks. It doesn’t have direction for who can use, preserve or destroy living things, such as bacteria or fungi, that may be discovered in space.

A semicircular room with dozens of people sitting at desks watching a big screen up front. CC BY-NC-ND.
The U.N. Committee on the Peaceful Uses of Outer Space is one of the few existing pathways for the governance of space. Image via United States Mission to International Organizations in Vienna.

Historical analogies and future pathways

While people have yet to discover extraterrestrial life of any kind, there are some major geopolitical events that can help researchers understand what the consequences might look like.

While the space race of the 1950s and ’60s led to exploration of the moon, it was driven by a Cold War power struggle between two nations back on Earth. Instead of coming together to explore space, both countries experienced a renewed sense of nationalism. They used the new discoveries that came from the space race to invest in their military capabilities.

On the other hand, researchers can look at how states respond to asteroid threats. Since an asteroid could pose a truly existential threat from space, preventing the worst-case scenario requires cooperation and thinking ahead.

Astronomers have built a global, collaborative network to monitor for and sound the alarm about any potential threats. This network has shown that nations can put aside terrestrial rivalries to work together if they perceive something from space as a truly existential threat.

The International Space Station is another example showing how nations that are competing great powers on Earth work together to cooperate in space. Countries have collaborated to solve issues on the International Space Station that have specific, short-term and clearly identified goals.

These examples show a range of possible reactions to the discovery of space microbes. The situation could renew space races between competing countries and lead to militarization, or it could create unprecedented cooperation.

Read on for the three main possible outcomes we’ve identified to the discovery of microbial extraterrestrial life.

A metal structure made of numerous linked cylinders, with large solar panels, floating in black space.
The ISS is an example of countries cooperating in space research. Image via NASA/ Roscosmos.

Cooperation

First, there’s a cooperative outcome, reminiscent of the asteroid threat network or the International Space Station. Here, nations collaborate to regulate research, share data, protect the planet or advance specific interests they share.

This pathway isn’t inherently benign or malignant. It could entail expanding the roles of international organizations or creating new legal instruments.

Competition

Second there’s a competitive outcome, characterized by strategic rivalry between countries. Like in the space race, nations could fight to be technologically superior. They might try to monopolize access to the extraterrestrial microbes or to leverage biological discoveries from the microbes for their own economic or military advantage.

Scientific breakthroughs derived from extraterrestrial organisms could lead to innovations in medicine, agriculture, energy and beyond. However, the organisms could also be weaponized, intentionally or otherwise, which would amplify biosecurity risks. In this sense, the discovery of microbial life could create a new form of technological competition, one that merges space exploration with biological research and development.

The increasing role of private companies, such as SpaceX, complicates this dynamic. These companies receive contracts from the government, blurring the lines between commercial civilian and strategic activities.

For example, around 60% of all satellites currently orbiting the Earth belong to SpaceX’s Starlink subsidiary. The company can – and has – chosen to block access selectively, in alignment with its political priorities. When commercial interests and national priorities diverge, who has access versus who is denied access can be uncertain.

Research around biopiracy may come into play. Biopiracy is a term that applies to two primary issues: the patenting of indigenous knowledge or the patenting of natural resources, such as microbes, for profit. The Budapest Treaty prohibits claiming ownership of a naturally occurring microbe on Earth, but there’s no equivalent for microbes in space.

Isolation

Third is an isolationist outcome, in which states could sever their involvement in international cooperation due to biosecurity concerns or political distrust. The potential for unknown biological risks, however minimal, could trigger precautionary restrictions on data sharing, which limits international collaboration.

Countries may lose or gain allies as they grapple with whether the microbe could cause harm to humans or the environment, or be developed into a biological weapon.

Emerging technologies will also shape these outcomes. Artificial intelligence and machine learning are already integral to scientific research. Scientists use them to process astronomical data and identify potential biosignatures. Nanotechnology and advances in the life sciences and engineering could allow researchers to study, modify or exploit extraterrestrial microbes, if they’re given access to them.

Countries will have to prepare not only for the scientific implications of discovery but also for its societal and political reverberations. The politicization of scientific discoveries from the microbes could complicate or change how countries respond domestically and at the international scale. Misinformation about the microbes could shape policy and public response.

Preparing for the unprecedented

The discovery of extraterrestrial microbial life would not merely mark a scientific milestone. It would be a geopolitical event.

Rather than attempting to predict a singular outcome, policymakers could adopt scenario-based planning approaches in the meantime to anticipate and prepare for a range of possibilities. In these approaches, participants explore multiple futures through structured activities similar to professional or military wargaming or path games, in which they explore multiple outcomes systematically to test strategies, to plan and to analyze potential outcomes under realistic uncertainty.

In our view, the question is not whether humanity will discover life beyond Earth, but whether it is prepared for the consequences when it does.The Conversation

Margaret E. Kosal, Georgia Institute of Technology; Dayana Alagirova, Georgia Institute of Technology, and Karryl Kim Sagun Trajano, Nanyang Technological University

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

Bottom line: If we ever find life beyond Earth, how will the nations of the world respond? A group of experts say there are three possibilities: cooperation, competition and isolation.

The post If we find life beyond Earth, how will nations respond? first appeared on EarthSky.



from EarthSky https://ift.tt/rEmqfRw
Life beyond Earth: Closeup, microscopic view of bumpy structures on a rock surface, one looking like a worm.
A super-closeup view of Mars meteorite ALH84001, found in Antarctica. What is that famous sub-micron-scale wormlike structure? If we ever do confirm life beyond Earth, how might the worlds’ nations respond? Experts think there are 3 possibilities. Image via NASA/ Wikimedia Commons.
  • Finding microbial life beyond Earth would be more than a scientific breakthrough. It has the potential to change how humanity thinks about itself.
  • Experts see three possible responses: nations could cooperate on research and regulation, or they could compete for scientific and economic advantages, or they could isolate themselves because of biosecurity concerns.
  • Policymakers can prepare now by using scenario planning to consider these possibilities, because the discovery of extraterrestrial life has the potential to bring both unprecedented cooperation and new forms of rivalry.

By Margaret E. Kosal, Georgia Institute of Technology; Dayana Alagirova, Georgia Institute of Technology, and Karryl Kim Sagun Trajano, Nanyang Technological University

If we find life beyond Earth, how will nations respond?

Microbes from space have fueled the plots of science fiction mainstays like Project Hail Mary and The Andromeda Strain. But with more space missions launching each year, finding extraterrestrial life in a microbial form is becoming more plausible. What will the response be back here on Earth if – or when – scientists discover extraterrestrial microbes? Will the international policy and security communities be prepared for the fallout?

When you hear about extraterrestrial life, your mind may go to intelligent life, like the kind present in a lot of Hollywood science fiction. But even the confirmation of microbial life that originated somewhere other than on Earth – which is much more likely – would be a paradigm-shifting event. Thinking about what these consequences might look like early on can help nations and the international community prepare.

Oblong tan and reddish irregular, textured rock.
This is the famous Martian meteorite ALH84001. Found in Antarctica, scientists for a time thought the meteorite from Mars showed evidence of life. Image via NASA/ Lunar and Planetary Institute.

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

Preparing for the possibility of life beyond Earth

Our team is interested in this question. We’re made up of a full professor of international affairs, who earned a Ph.D. in chemistry, and whose expertise is on how emerging science and technologies could affect global conflict and cooperation, as well as an emerging scholar in space policy and security and an expert on social and political implications of frontier technologies, such as AI, space, quantum and energy sources.

Multiple Mars landers have identified large amounts of frozen and liquid water, essential for life, on the red planet. Samples retrieved by Japan’s Hayabusa2 spacecraft from a near-Earth asteroid revealed the presence of uracil, part of RNA, which is a building block of life. Uncrewed space probes like NASA’s Europa Clipper and the European Space Agency’s Jupiter Icy Moons Explorer are on their way to conduct detailed reconnaissance of the planet’s moons and to investigate whether they have conditions suitable for life.

Along with data from the James Webb Space Telescope and future missions targeting Saturn’s icy moon Enceladus, the likelihood of discovering extraterrestrial microbial life has increased substantially.

Scientists are searching for life in space using what they know about life on Earth. But what will happen if or when they find something?

A governance challenge

The discovery of microbial life would expose significant gaps in international governance related to space.

While there are some existing international agreements, including the Outer Space Treaty, that provide space law guidelines, these are ill-equipped to address the complexities posed by extraterrestrial biology.

The Outer Space Treaty, established in 1967, dictates that countries should use outer space peacefully. It also states that no single nation may claim ownership or exert sovereignty over parts of outer space or celestial bodies such as the moon.

However, it doesn’t have much to say about who can own extraterrestrial organisms or what to do about biosecurity risks. It doesn’t have direction for who can use, preserve or destroy living things, such as bacteria or fungi, that may be discovered in space.

A semicircular room with dozens of people sitting at desks watching a big screen up front. CC BY-NC-ND.
The U.N. Committee on the Peaceful Uses of Outer Space is one of the few existing pathways for the governance of space. Image via United States Mission to International Organizations in Vienna.

Historical analogies and future pathways

While people have yet to discover extraterrestrial life of any kind, there are some major geopolitical events that can help researchers understand what the consequences might look like.

While the space race of the 1950s and ’60s led to exploration of the moon, it was driven by a Cold War power struggle between two nations back on Earth. Instead of coming together to explore space, both countries experienced a renewed sense of nationalism. They used the new discoveries that came from the space race to invest in their military capabilities.

On the other hand, researchers can look at how states respond to asteroid threats. Since an asteroid could pose a truly existential threat from space, preventing the worst-case scenario requires cooperation and thinking ahead.

Astronomers have built a global, collaborative network to monitor for and sound the alarm about any potential threats. This network has shown that nations can put aside terrestrial rivalries to work together if they perceive something from space as a truly existential threat.

The International Space Station is another example showing how nations that are competing great powers on Earth work together to cooperate in space. Countries have collaborated to solve issues on the International Space Station that have specific, short-term and clearly identified goals.

These examples show a range of possible reactions to the discovery of space microbes. The situation could renew space races between competing countries and lead to militarization, or it could create unprecedented cooperation.

Read on for the three main possible outcomes we’ve identified to the discovery of microbial extraterrestrial life.

A metal structure made of numerous linked cylinders, with large solar panels, floating in black space.
The ISS is an example of countries cooperating in space research. Image via NASA/ Roscosmos.

Cooperation

First, there’s a cooperative outcome, reminiscent of the asteroid threat network or the International Space Station. Here, nations collaborate to regulate research, share data, protect the planet or advance specific interests they share.

This pathway isn’t inherently benign or malignant. It could entail expanding the roles of international organizations or creating new legal instruments.

Competition

Second there’s a competitive outcome, characterized by strategic rivalry between countries. Like in the space race, nations could fight to be technologically superior. They might try to monopolize access to the extraterrestrial microbes or to leverage biological discoveries from the microbes for their own economic or military advantage.

Scientific breakthroughs derived from extraterrestrial organisms could lead to innovations in medicine, agriculture, energy and beyond. However, the organisms could also be weaponized, intentionally or otherwise, which would amplify biosecurity risks. In this sense, the discovery of microbial life could create a new form of technological competition, one that merges space exploration with biological research and development.

The increasing role of private companies, such as SpaceX, complicates this dynamic. These companies receive contracts from the government, blurring the lines between commercial civilian and strategic activities.

For example, around 60% of all satellites currently orbiting the Earth belong to SpaceX’s Starlink subsidiary. The company can – and has – chosen to block access selectively, in alignment with its political priorities. When commercial interests and national priorities diverge, who has access versus who is denied access can be uncertain.

Research around biopiracy may come into play. Biopiracy is a term that applies to two primary issues: the patenting of indigenous knowledge or the patenting of natural resources, such as microbes, for profit. The Budapest Treaty prohibits claiming ownership of a naturally occurring microbe on Earth, but there’s no equivalent for microbes in space.

Isolation

Third is an isolationist outcome, in which states could sever their involvement in international cooperation due to biosecurity concerns or political distrust. The potential for unknown biological risks, however minimal, could trigger precautionary restrictions on data sharing, which limits international collaboration.

Countries may lose or gain allies as they grapple with whether the microbe could cause harm to humans or the environment, or be developed into a biological weapon.

Emerging technologies will also shape these outcomes. Artificial intelligence and machine learning are already integral to scientific research. Scientists use them to process astronomical data and identify potential biosignatures. Nanotechnology and advances in the life sciences and engineering could allow researchers to study, modify or exploit extraterrestrial microbes, if they’re given access to them.

Countries will have to prepare not only for the scientific implications of discovery but also for its societal and political reverberations. The politicization of scientific discoveries from the microbes could complicate or change how countries respond domestically and at the international scale. Misinformation about the microbes could shape policy and public response.

Preparing for the unprecedented

The discovery of extraterrestrial microbial life would not merely mark a scientific milestone. It would be a geopolitical event.

Rather than attempting to predict a singular outcome, policymakers could adopt scenario-based planning approaches in the meantime to anticipate and prepare for a range of possibilities. In these approaches, participants explore multiple futures through structured activities similar to professional or military wargaming or path games, in which they explore multiple outcomes systematically to test strategies, to plan and to analyze potential outcomes under realistic uncertainty.

In our view, the question is not whether humanity will discover life beyond Earth, but whether it is prepared for the consequences when it does.The Conversation

Margaret E. Kosal, Georgia Institute of Technology; Dayana Alagirova, Georgia Institute of Technology, and Karryl Kim Sagun Trajano, Nanyang Technological University

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

Bottom line: If we ever find life beyond Earth, how will the nations of the world respond? A group of experts say there are three possibilities: cooperation, competition and isolation.

The post If we find life beyond Earth, how will nations respond? first appeared on EarthSky.



from EarthSky https://ift.tt/rEmqfRw

Octans and Apus circle the south celestial pole

Star chart: 2 dim constellations and their outlines with faint drawings of the objects they are supposed to be.
Octans and Apus (the Octant and the Bird of Paradise, respectively) lie far south. In fact, Octans is home to the south celestial pole. Be sure to look for them from the Southern Hemisphere on September evenings. Chart via EarthSky.

Octans and Apus

Octans the Octant and Apus the Bird of Paradise circle the south celestial pole. If you want to see them, you’ll have to be in the Southern Hemisphere. In fact, the south celestial pole lies inside the constellation boundary for Octans.

Both of these constellations are south circumpolar constellations. Of course, the north has circumpolar constellations too. Constellations such as Ursa Minor, Ursa Major and Draco can be seen any night of the year from the Northern Hemisphere. Octans and Apus are two constellations that Southern Hemisphere observers can view on any clear evening.

Octans the Octant

And Octans is a key constellation for another reason. When we look in its direction in space, we are looking toward Earth’s south celestial pole. Polaris is the famous star marking the location of the north celestial pole. But the Southern Hemisphere has no bright star near its celestial pole. That is why you might hear astronomers say there’s no pole star for the Southern Hemisphere sky.

There is an extremely dim galaxy that’s nearly at the location of the south celestial pole. And that galaxy has the fitting name of Polarissima Australis. It shines much too dimly to be viewed without optical aid, at magnitude 13.5.

The brightest star in Octans is only moderately bright at +3.7 magnitude. It is Nu Octantis, a double star, located some 69 light-years away. The star is home to a confirmed super-Jovian exoplanet. So far, no other planets have been found in the Nu Octantis system.

White chart with radial grid and black dots for stars outlining the shape of Octans.
Star chart for Octans the Octant. The location where all the lines converge marks the south celestial pole. Chart via IAU/ Sky and Telescope/ Wikimedia Commons.

Apus the Bird of Paradise

Then, next to Octans, is Apus the Bird of Paradise. It’s small and ranked 67th in size out of the 88 constellations. It lies between Octans and Triangulum Australe the Southern Triangle. The stars in Apus are quite dim. The brightest member of the constellation is Alpha Apodis at magnitude 3.83. Alpha Apodis lies about 430 light-years from Earth. Slightly fainter is Gamma Apodis at magnitude 3.86 and 150 light-years distant. This star is a strong source of X-rays.

White chart with radial grid and black dots for stars showing Apus.
Star chart for Apus the Bird of Paradise. Chart via IAU/ Sky and Telescope/ Wikimedia Commons.

Bottom line: Octans and Apus are two constellations that you have to be in the Southern Hemisphere to see. Plus, Octans is home to the south celestial pole.

The post Octans and Apus circle the south celestial pole first appeared on EarthSky.



from EarthSky https://ift.tt/ORPx2wj
Star chart: 2 dim constellations and their outlines with faint drawings of the objects they are supposed to be.
Octans and Apus (the Octant and the Bird of Paradise, respectively) lie far south. In fact, Octans is home to the south celestial pole. Be sure to look for them from the Southern Hemisphere on September evenings. Chart via EarthSky.

Octans and Apus

Octans the Octant and Apus the Bird of Paradise circle the south celestial pole. If you want to see them, you’ll have to be in the Southern Hemisphere. In fact, the south celestial pole lies inside the constellation boundary for Octans.

Both of these constellations are south circumpolar constellations. Of course, the north has circumpolar constellations too. Constellations such as Ursa Minor, Ursa Major and Draco can be seen any night of the year from the Northern Hemisphere. Octans and Apus are two constellations that Southern Hemisphere observers can view on any clear evening.

Octans the Octant

And Octans is a key constellation for another reason. When we look in its direction in space, we are looking toward Earth’s south celestial pole. Polaris is the famous star marking the location of the north celestial pole. But the Southern Hemisphere has no bright star near its celestial pole. That is why you might hear astronomers say there’s no pole star for the Southern Hemisphere sky.

There is an extremely dim galaxy that’s nearly at the location of the south celestial pole. And that galaxy has the fitting name of Polarissima Australis. It shines much too dimly to be viewed without optical aid, at magnitude 13.5.

The brightest star in Octans is only moderately bright at +3.7 magnitude. It is Nu Octantis, a double star, located some 69 light-years away. The star is home to a confirmed super-Jovian exoplanet. So far, no other planets have been found in the Nu Octantis system.

White chart with radial grid and black dots for stars outlining the shape of Octans.
Star chart for Octans the Octant. The location where all the lines converge marks the south celestial pole. Chart via IAU/ Sky and Telescope/ Wikimedia Commons.

Apus the Bird of Paradise

Then, next to Octans, is Apus the Bird of Paradise. It’s small and ranked 67th in size out of the 88 constellations. It lies between Octans and Triangulum Australe the Southern Triangle. The stars in Apus are quite dim. The brightest member of the constellation is Alpha Apodis at magnitude 3.83. Alpha Apodis lies about 430 light-years from Earth. Slightly fainter is Gamma Apodis at magnitude 3.86 and 150 light-years distant. This star is a strong source of X-rays.

White chart with radial grid and black dots for stars showing Apus.
Star chart for Apus the Bird of Paradise. Chart via IAU/ Sky and Telescope/ Wikimedia Commons.

Bottom line: Octans and Apus are two constellations that you have to be in the Southern Hemisphere to see. Plus, Octans is home to the south celestial pole.

The post Octans and Apus circle the south celestial pole first appeared on EarthSky.



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Mars’ southern hemisphere is unusually hot deep underground

Mars' southern hemisphere: A reddish rocky planet split in half. The interior of one half has a bright whitish center and a speckled mantle.
View larger. | Cutaway view of Mars showing the interior of the planet. Researchers have discovered evidence for excess heat in Mars’ southern hemisphere, deep below the surface. Image via NASA/ Theophilus Britt Griswold.
  • Mars is a cold world, with ice caps and lots of ice below the surface.
  • But new research has discovered strange excess heat deep below the surface of southern hemisphere.
  • Explanations range from a giant impact releasing thermal energy to thick geological features trapping heat.

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

Mars’ southern hemisphere is unexpectedly hot deep below the surface

Mars is a very cold planet on the surface. Like Earth, it gradually gets warmer the deeper you go into its interior. But now, researchers at Caltech in California have found an unusual anomaly. They said on August 26, 2026, that there’s a huge excess of heat deep below Mars’ surface in the southern hemisphere. In fact, the region is about 200-400 degrees Celsius (290-750 degrees Fahrenheit) hotter than expected.

The heat anomaly seems to mirror the north-south asymmetry of Mars. The planet’s northern hemisphere is mostly flat lowlands, while the southern hemisphere is covered by craters and mountains. Because of this, Mars sometimes is referred to as as being “two-faced.” Now it seems that rather than being simply a surface feature, that characteristic runs deep into the inside of the planet as well.

The researchers published their peer-reviewed findings in Nature on August 26, 2026.

Measuring spacecraft velocities

How did the researchers discover this anomaly? Caltech alumnus Alexander Berne led the new study. Berne and his team used data collected over decades from three different Mars missions: Mars Global Surveyor, Mars Odyssey and Mars Reconnaissance Orbiter. The team measured tiny variations in the spacecrafts’ velocities and then used them to reconstruct the gravitational field around Mars.

Using a technique called tidal tomography, or planetary tomography, the researchers measured how those gravitational signatures vary over time. This enabled the team to create a model of the planet’s interior. As Berne explained:

Scientists usually assume that the interiors of planetary bodies are generally spherically symmetric, but this is not necessarily true. As we get more gravity data, we can determine the three-dimensional intricacies of a planet’s interior structure. These inferences in turn give us a blueprint for designing future missions and scientific exploration of these worlds. Understanding the interior structure of planetary bodies helps us unravel the processes that shaped their formation and evolution.

Cutaway view of a rocky planet. The inner part is bright yellow and the outer is red-orange. With text labels.
View larger. | This diagram depicts the cold interior of the northern hemisphere and the warm interior of the southern hemisphere. Image via Berne et al./ Nature.
Map of a rocky planet, with most of the northern part in blue and the lower part in red, yellow and green.
View larger. | Map showing Mars’ topography. The planet’s northern and southern hemispheres are very different; the north is mostly flat lowlands, while the south is covered in craters and mountains. Image via NASA/ JPL/ USGS/ Wikipedia.

An unbalanced interior

Like Earth, Mars isn’t perfectly spherical. The northern lowlands are mostly quite flat, while the southern hemisphere has mountains and many deep craters. And this is where the thermal anomaly comes in. The interior of the southern hemisphere is much hotter than the north, by about 200-400 degrees Celsius (290-750 degrees Fahrenheit). At those temperatures, the rock is partially molten.

Smiling man with handlebar moustache.
Alexander Berne at Caltech led the new study about the interior of Mars. Image via Alexander Berne.

What could explain Mars’ southern hemisphere anomaly?

The researchers have proposed a few hypotheses to explain the anomaly. One is a giant impact that released heat from the northern hemisphere.

Another possibility is spontaneous convection – the movement of heat through fluids – in the southern mantle.

Finally, it could be caused by thick geological features in the southern hemisphere that trap excess heat from escaping.

The findings also have implications for the geological history of Mars and its habitability billions of years ago. Co-author Amirhossein Bagheri, a postdoctoral scholar at Caltech, said:

The dichotomy that we see between north and south is important to understand because it gives information about processes that may have influenced the hydrology of Mars, including the formation of basins that may have held water.

Bottom line: A new study from Caltech shows that Mars’ southern hemisphere is much hotter than expected deep below the surface. Why is that?

Source: Tidal tomography reveals a thermal anomaly beneath Mars’s crustal dichotomy

Via Caltech

Read more: Mars’ interior might contain remnants of baby planets

Read more: Marsquakes might explain Mars’ north-south hemisphere differences

The post Mars’ southern hemisphere is unusually hot deep underground first appeared on EarthSky.



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Mars' southern hemisphere: A reddish rocky planet split in half. The interior of one half has a bright whitish center and a speckled mantle.
View larger. | Cutaway view of Mars showing the interior of the planet. Researchers have discovered evidence for excess heat in Mars’ southern hemisphere, deep below the surface. Image via NASA/ Theophilus Britt Griswold.
  • Mars is a cold world, with ice caps and lots of ice below the surface.
  • But new research has discovered strange excess heat deep below the surface of southern hemisphere.
  • Explanations range from a giant impact releasing thermal energy to thick geological features trapping heat.

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

Mars’ southern hemisphere is unexpectedly hot deep below the surface

Mars is a very cold planet on the surface. Like Earth, it gradually gets warmer the deeper you go into its interior. But now, researchers at Caltech in California have found an unusual anomaly. They said on August 26, 2026, that there’s a huge excess of heat deep below Mars’ surface in the southern hemisphere. In fact, the region is about 200-400 degrees Celsius (290-750 degrees Fahrenheit) hotter than expected.

The heat anomaly seems to mirror the north-south asymmetry of Mars. The planet’s northern hemisphere is mostly flat lowlands, while the southern hemisphere is covered by craters and mountains. Because of this, Mars sometimes is referred to as as being “two-faced.” Now it seems that rather than being simply a surface feature, that characteristic runs deep into the inside of the planet as well.

The researchers published their peer-reviewed findings in Nature on August 26, 2026.

Measuring spacecraft velocities

How did the researchers discover this anomaly? Caltech alumnus Alexander Berne led the new study. Berne and his team used data collected over decades from three different Mars missions: Mars Global Surveyor, Mars Odyssey and Mars Reconnaissance Orbiter. The team measured tiny variations in the spacecrafts’ velocities and then used them to reconstruct the gravitational field around Mars.

Using a technique called tidal tomography, or planetary tomography, the researchers measured how those gravitational signatures vary over time. This enabled the team to create a model of the planet’s interior. As Berne explained:

Scientists usually assume that the interiors of planetary bodies are generally spherically symmetric, but this is not necessarily true. As we get more gravity data, we can determine the three-dimensional intricacies of a planet’s interior structure. These inferences in turn give us a blueprint for designing future missions and scientific exploration of these worlds. Understanding the interior structure of planetary bodies helps us unravel the processes that shaped their formation and evolution.

Cutaway view of a rocky planet. The inner part is bright yellow and the outer is red-orange. With text labels.
View larger. | This diagram depicts the cold interior of the northern hemisphere and the warm interior of the southern hemisphere. Image via Berne et al./ Nature.
Map of a rocky planet, with most of the northern part in blue and the lower part in red, yellow and green.
View larger. | Map showing Mars’ topography. The planet’s northern and southern hemispheres are very different; the north is mostly flat lowlands, while the south is covered in craters and mountains. Image via NASA/ JPL/ USGS/ Wikipedia.

An unbalanced interior

Like Earth, Mars isn’t perfectly spherical. The northern lowlands are mostly quite flat, while the southern hemisphere has mountains and many deep craters. And this is where the thermal anomaly comes in. The interior of the southern hemisphere is much hotter than the north, by about 200-400 degrees Celsius (290-750 degrees Fahrenheit). At those temperatures, the rock is partially molten.

Smiling man with handlebar moustache.
Alexander Berne at Caltech led the new study about the interior of Mars. Image via Alexander Berne.

What could explain Mars’ southern hemisphere anomaly?

The researchers have proposed a few hypotheses to explain the anomaly. One is a giant impact that released heat from the northern hemisphere.

Another possibility is spontaneous convection – the movement of heat through fluids – in the southern mantle.

Finally, it could be caused by thick geological features in the southern hemisphere that trap excess heat from escaping.

The findings also have implications for the geological history of Mars and its habitability billions of years ago. Co-author Amirhossein Bagheri, a postdoctoral scholar at Caltech, said:

The dichotomy that we see between north and south is important to understand because it gives information about processes that may have influenced the hydrology of Mars, including the formation of basins that may have held water.

Bottom line: A new study from Caltech shows that Mars’ southern hemisphere is much hotter than expected deep below the surface. Why is that?

Source: Tidal tomography reveals a thermal anomaly beneath Mars’s crustal dichotomy

Via Caltech

Read more: Mars’ interior might contain remnants of baby planets

Read more: Marsquakes might explain Mars’ north-south hemisphere differences

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Cassiopeia the Queen ascends in September and October


Do you want to know more about the constellation Cassiopeia the Queen? Watch this video for more details.

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Cassiopeia the Queen in autumn

Any late summer evening and throughout northern autumn, Cassiopeia the Queen will be ascending in the northeast after nightfall. The shape of this constellation makes Cassiopeia’s stars very noticeable. Cassiopeia looks like the letter W (or M).

Look for the Queen at nightfall in September, and notice how she gets higher in the northeast with each day as northern autumn unfolds.

For those at the latitudes of the northern U.S. and Canada, Cassiopeia is circumpolar. That means the constellation stays above the horizon all night, every night.

How to see Cassiopeia

Cassiopeia represents an ancient queen of Ethiopia. You still sometimes hear the old name for this constellation: Cassiopeia’s Chair. And some old star maps depict the queen sitting on the chair, marked by five stars.

These stars – the brightest ones in Cassiopeia – are Schedar, Caph, Gamma Cassiopeiae, Ruchbah and Segin.

Around the middle of the night during the autumn months, Cassiopeia swings above Polaris, the North Star.

Before dawn, look in the northwest.

Star chart of constellation Cassiopeia with stars labeled and two tiny, labeled rings of dots.
You can find Cassiopeia the Queen in the northeast around the month of September. If you have a dark sky, look below Cassiopeia for a famous binocular object. This object is called the Double Cluster in Perseus. Chart via EarthSky.

Opposite the Big Dipper

Cassiopeia is opposite the Big Dipper in the northern sky.

That is, the two constellations lie on opposite sides of the pole star, Polaris.

So when Cassiopeia is high in the sky, as it is on evenings from about September through February, the Big Dipper is low in the sky. Every March, when the Dipper is ascending in the northeast, getting ready to appear prominent again in the evening sky, Cassiopeia is descending in the northwest.

Animated diagram of Cassiopeia stars and Big Dipper circling around Polaris in the center.
The Big Dipper and the W-shaped constellation Cassiopeia circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude, and all latitudes farther north. Image via Mjchael/ Wikipedia.

A guide to deep-sky beauties

If you have a dark sky, look below Cassiopeia in the northeast on these autumn evenings for the Double Cluster in Perseus.

These are two open star clusters. Each consists of young stars still moving together from the primordial cloud of gas and dust that gave birth to them.

These two clusters are familiarly known to stargazers as H and Chi Persei.

Interestingly, their names are from two different alphabets, the Greek and the Roman. Stars have Greek letter names, but most star clusters don’t. Johann Bayer (1572-1625) gave Chi Persei its Greek letter name. Then, it’s said, he ran out of Greek letters. That’s when he used a Roman letter – the letter H – to name the other cluster.

Charts for Cassiopeia

Sky chart of constellation Cassiopeia with stars in black on white and other objects as small colored symbols.
In the 1930s, the International Astronomical Union (IAU) – an organization of professional astronomers – decided to define boundaries and officially name 88 constellations. This is the realm of night sky they identified as Cassiopeia. Read more about the constellations. Image via IAU.
Old-fashioned drawing of Queen Cassiopeia in Greek garb on her throne, with scattered stars.
Cassiopeia as Johannes Hevelius depicted it in the 1600s. Image via Wikimedia Commons.

Lore of Cassiopeia

In skylore and in Greek mythology, Cassiopeia is a beautiful and vain queen of Ethiopia. It’s said that she committed the sin of pride by boasting that both she and her daughter Andromeda were more beautiful than Nereids, or sea nymphs. Pridefulness, in mythology, is never wise.

Since her boast angered Poseidon, God of the Sea, he sent a sea monster (Cetus the Whale) to ravage the kingdom. So to pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero happened by on Pegasus, the Flying Horse.

Perseus rescued the princess, and all lived happily … and the gods were pleased, so all of these characters were elevated to the heavens as stars.

But – because of her vanity – Cassiopeia suffered an indignity. At some times of the night or year, this constellation has more the shape of the letter M, and you might imagine the Queen reclining on her starry throne.

At other times of year or night – as in the wee hours between midnight and dawn in February and March – Cassiopeia’s Chair dips below the celestial pole. And then this constellation appears to us on Earth more like the letter W. That’s when the Lady of the Chair, as astronomers sometimes call her, is said to hang on for dear life. If Cassiopeia the Queen lets go, she will drop from the sky into the ocean below, where the Nereids must still be waiting.

Cassiopeia by our EarthSky Community

Starry sky with a bright Perseid by Cassiopeia. There's a lighthouse to the right.
View at EarthSky Community Photos. | Enrico Modica captured this photo on August 13, 2026, in Italy. Enrico wrote: “This image shows the Plemmirio Lighthouse near Syracuse, Sicily, beneath the summer night sky, with the constellations of Andromeda, Cassiopeia, and Perseus, as well as the Andromeda Galaxy (M31), approximately 2.5 million light-years away. A Perseid meteor is also visible on the left side of the frame right by Cassiopeia.” Thank you, Enrico!
Broad agricultural fields, with Cassiopeia shining through wispy clouds.
View at EarthSky Community Photos. | V. Liard Photography in Champagne, France, took this wonderful image on July 22, 2023. It features the W-shaped constellation Cassiopeia the Queen. Thank you, V. Liard! Cassiopeia is a great constellation to come to know, especially if you have a dark sky. That’s because it points to our neighbor, the Andromeda galaxy.

Bottom line: Cassiopeia the Queen is an easy-to-find constellation. It has the shape of a W or M. Look for it in the north-northeast sky on September and October evenings.

Help support EarthSky! Visit the EarthSky store to see the great selection of educational tools and team gear we have to offer.

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

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Do you want to know more about the constellation Cassiopeia the Queen? Watch this video for more details.

Don’t miss the next unmissable night sky event. Sign up to EarthSky’s free newsletter for daily night sky updates.

Cassiopeia the Queen in autumn

Any late summer evening and throughout northern autumn, Cassiopeia the Queen will be ascending in the northeast after nightfall. The shape of this constellation makes Cassiopeia’s stars very noticeable. Cassiopeia looks like the letter W (or M).

Look for the Queen at nightfall in September, and notice how she gets higher in the northeast with each day as northern autumn unfolds.

For those at the latitudes of the northern U.S. and Canada, Cassiopeia is circumpolar. That means the constellation stays above the horizon all night, every night.

How to see Cassiopeia

Cassiopeia represents an ancient queen of Ethiopia. You still sometimes hear the old name for this constellation: Cassiopeia’s Chair. And some old star maps depict the queen sitting on the chair, marked by five stars.

These stars – the brightest ones in Cassiopeia – are Schedar, Caph, Gamma Cassiopeiae, Ruchbah and Segin.

Around the middle of the night during the autumn months, Cassiopeia swings above Polaris, the North Star.

Before dawn, look in the northwest.

Star chart of constellation Cassiopeia with stars labeled and two tiny, labeled rings of dots.
You can find Cassiopeia the Queen in the northeast around the month of September. If you have a dark sky, look below Cassiopeia for a famous binocular object. This object is called the Double Cluster in Perseus. Chart via EarthSky.

Opposite the Big Dipper

Cassiopeia is opposite the Big Dipper in the northern sky.

That is, the two constellations lie on opposite sides of the pole star, Polaris.

So when Cassiopeia is high in the sky, as it is on evenings from about September through February, the Big Dipper is low in the sky. Every March, when the Dipper is ascending in the northeast, getting ready to appear prominent again in the evening sky, Cassiopeia is descending in the northwest.

Animated diagram of Cassiopeia stars and Big Dipper circling around Polaris in the center.
The Big Dipper and the W-shaped constellation Cassiopeia circle around Polaris, the North Star, in a period of 23 hours and 56 minutes. The Dipper is circumpolar at 41 degrees north latitude, and all latitudes farther north. Image via Mjchael/ Wikipedia.

A guide to deep-sky beauties

If you have a dark sky, look below Cassiopeia in the northeast on these autumn evenings for the Double Cluster in Perseus.

These are two open star clusters. Each consists of young stars still moving together from the primordial cloud of gas and dust that gave birth to them.

These two clusters are familiarly known to stargazers as H and Chi Persei.

Interestingly, their names are from two different alphabets, the Greek and the Roman. Stars have Greek letter names, but most star clusters don’t. Johann Bayer (1572-1625) gave Chi Persei its Greek letter name. Then, it’s said, he ran out of Greek letters. That’s when he used a Roman letter – the letter H – to name the other cluster.

Charts for Cassiopeia

Sky chart of constellation Cassiopeia with stars in black on white and other objects as small colored symbols.
In the 1930s, the International Astronomical Union (IAU) – an organization of professional astronomers – decided to define boundaries and officially name 88 constellations. This is the realm of night sky they identified as Cassiopeia. Read more about the constellations. Image via IAU.
Old-fashioned drawing of Queen Cassiopeia in Greek garb on her throne, with scattered stars.
Cassiopeia as Johannes Hevelius depicted it in the 1600s. Image via Wikimedia Commons.

Lore of Cassiopeia

In skylore and in Greek mythology, Cassiopeia is a beautiful and vain queen of Ethiopia. It’s said that she committed the sin of pride by boasting that both she and her daughter Andromeda were more beautiful than Nereids, or sea nymphs. Pridefulness, in mythology, is never wise.

Since her boast angered Poseidon, God of the Sea, he sent a sea monster (Cetus the Whale) to ravage the kingdom. So to pacify the monster, Cassiopeia’s daughter, Princess Andromeda, was left tied to a rock by the sea. Cetus was about to devour her when Perseus the Hero happened by on Pegasus, the Flying Horse.

Perseus rescued the princess, and all lived happily … and the gods were pleased, so all of these characters were elevated to the heavens as stars.

But – because of her vanity – Cassiopeia suffered an indignity. At some times of the night or year, this constellation has more the shape of the letter M, and you might imagine the Queen reclining on her starry throne.

At other times of year or night – as in the wee hours between midnight and dawn in February and March – Cassiopeia’s Chair dips below the celestial pole. And then this constellation appears to us on Earth more like the letter W. That’s when the Lady of the Chair, as astronomers sometimes call her, is said to hang on for dear life. If Cassiopeia the Queen lets go, she will drop from the sky into the ocean below, where the Nereids must still be waiting.

Cassiopeia by our EarthSky Community

Starry sky with a bright Perseid by Cassiopeia. There's a lighthouse to the right.
View at EarthSky Community Photos. | Enrico Modica captured this photo on August 13, 2026, in Italy. Enrico wrote: “This image shows the Plemmirio Lighthouse near Syracuse, Sicily, beneath the summer night sky, with the constellations of Andromeda, Cassiopeia, and Perseus, as well as the Andromeda Galaxy (M31), approximately 2.5 million light-years away. A Perseid meteor is also visible on the left side of the frame right by Cassiopeia.” Thank you, Enrico!
Broad agricultural fields, with Cassiopeia shining through wispy clouds.
View at EarthSky Community Photos. | V. Liard Photography in Champagne, France, took this wonderful image on July 22, 2023. It features the W-shaped constellation Cassiopeia the Queen. Thank you, V. Liard! Cassiopeia is a great constellation to come to know, especially if you have a dark sky. That’s because it points to our neighbor, the Andromeda galaxy.

Bottom line: Cassiopeia the Queen is an easy-to-find constellation. It has the shape of a W or M. Look for it in the north-northeast sky on September and October evenings.

Help support EarthSky! Visit the EarthSky store to see the great selection of educational tools and team gear we have to offer.

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

The post Cassiopeia the Queen ascends in September and October first appeared on EarthSky.



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BepiColombo mission 1 step closer to Mercury today

BepiColombo: Black and white image of a spacecraft arm with a cratered world behind it.
View larger. | This view of Mercury from the BepiColombo spacecraft came from its 3rd flyby of the planet on June 19, 2023. BepiColombo’s propulsion system will separate from its 2 orbiters on September 3, 2026. Then the 2 spacecraft will enter orbit around Mercury on November 21, 2026. Image via ESA/ BepiColombo/ MTM.

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

BepiColombo mission to arrive at Mercury in November

Today, on September 3, 2026, ESA’s BepiColombo spacecraft is moving one crucial step closer to entering Mercury’s orbit.

Bepicolombo launched to space way back October 20, 2018, from Kourou, French Guiana. The spacecraft has spent eight years maneuvering into position so that it can orbit Mercury, the closest planet to the sun. Orbiting Mercury is a true engineering challenge, because the spacecraft picks up speed as it nears the massive sun. But it must slow down to enter Mercury’s orbit and not fly straight past.

So, during its journey, BepiColombo has made flybys of Earth, Venus and Mercury to help put on the brakes. And on September 3, 2026, Bepicolombo’s Mercury Transfer Module (the spacecraft’s propulsion unit) will separate from the science orbiters, Mercury Planetary Orbiter (MPO) and Mercury Magnetospheric Orbiter (MMO). These two spacecraft will then enter orbit around Mercury on November 21, 2026.

On December 9-10, the two orbiters will separate from each other. Finally, science operations will begin in April 2027.

BepiColombo’s flybys

BepiColombo has made one Earth flyby, two Venus flybys, and six Mercury flybys since its launch in 2018. Click the links below to learn more about the flybys.

April 10, 2020: 1st Earth flyby
October 15, 2020: 1st Venus flyby
August 10, 2021: 2nd Venus flyby
October 1, 2021: 1st Mercury flyby
June 23, 2022: 2nd Mercury flyby
June 20, 2023: 3rd Mercury flyby
September 4, 2024: 4th Mercury flyby
December 1, 2024: 5th Mercury flyby
January 8, 2025: 6th Mercury flyby

View larger. | The European Space Agency’s BepiColombo spacecraft, heading toward Mercury, caught this fleeting image of Venus on October 15, 2020. You can see the terminator line, or dividing line between light and dark on Venus, pass from right to left, causing Venus to change phase as the spacecraft swept past. Image via ESA/ BepiColombo/ MTM.

What scientists hope to learn at Mercury

Mercury is currently the least-understood planet in the inner solar system. In fact, before BepiColombo, the only spacecraft to have visited Mercury were NASA’s Mariner 10 and MESSENGER missions.

Now, scientists hope to solve five mysteries with BepiColombo:

  1. Where did Mercury come from?
  2. Is there really water on Mercury?
  3. Is Mercury dead or alive?
  4. Why is Mercury so dark?
  5. Why does Mercury have a magnetic field?

To answer these questions, BepiColombo will spend at least one year orbiting Mercury. The mission will use its high-resolution instruments to learn about the mineralogical and elemental composition of Mercury’s surface. Plus, it will scan polar regions for ice. BepiColombo will look for anything that looks like it has changed on Mercury since MESSENGER visited 10 years earlier. And the two orbiters will travel through different areas of the planet’s magnetosphere to measure how it changes and interacts with the sun.

Bottom line: The BepiColombo mission has been maneuvering its way into orbit around Mercury for eight years. On September 3, it will release two orbiters in Mercury orbit.

Via ESA

Read more: Mercury images from final flyby of BepiColombo!

Read more: Mercury lives on? Strange streaks hint at active world

The post BepiColombo mission 1 step closer to Mercury today first appeared on EarthSky.



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BepiColombo: Black and white image of a spacecraft arm with a cratered world behind it.
View larger. | This view of Mercury from the BepiColombo spacecraft came from its 3rd flyby of the planet on June 19, 2023. BepiColombo’s propulsion system will separate from its 2 orbiters on September 3, 2026. Then the 2 spacecraft will enter orbit around Mercury on November 21, 2026. Image via ESA/ BepiColombo/ MTM.

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

BepiColombo mission to arrive at Mercury in November

Today, on September 3, 2026, ESA’s BepiColombo spacecraft is moving one crucial step closer to entering Mercury’s orbit.

Bepicolombo launched to space way back October 20, 2018, from Kourou, French Guiana. The spacecraft has spent eight years maneuvering into position so that it can orbit Mercury, the closest planet to the sun. Orbiting Mercury is a true engineering challenge, because the spacecraft picks up speed as it nears the massive sun. But it must slow down to enter Mercury’s orbit and not fly straight past.

So, during its journey, BepiColombo has made flybys of Earth, Venus and Mercury to help put on the brakes. And on September 3, 2026, Bepicolombo’s Mercury Transfer Module (the spacecraft’s propulsion unit) will separate from the science orbiters, Mercury Planetary Orbiter (MPO) and Mercury Magnetospheric Orbiter (MMO). These two spacecraft will then enter orbit around Mercury on November 21, 2026.

On December 9-10, the two orbiters will separate from each other. Finally, science operations will begin in April 2027.

BepiColombo’s flybys

BepiColombo has made one Earth flyby, two Venus flybys, and six Mercury flybys since its launch in 2018. Click the links below to learn more about the flybys.

April 10, 2020: 1st Earth flyby
October 15, 2020: 1st Venus flyby
August 10, 2021: 2nd Venus flyby
October 1, 2021: 1st Mercury flyby
June 23, 2022: 2nd Mercury flyby
June 20, 2023: 3rd Mercury flyby
September 4, 2024: 4th Mercury flyby
December 1, 2024: 5th Mercury flyby
January 8, 2025: 6th Mercury flyby

View larger. | The European Space Agency’s BepiColombo spacecraft, heading toward Mercury, caught this fleeting image of Venus on October 15, 2020. You can see the terminator line, or dividing line between light and dark on Venus, pass from right to left, causing Venus to change phase as the spacecraft swept past. Image via ESA/ BepiColombo/ MTM.

What scientists hope to learn at Mercury

Mercury is currently the least-understood planet in the inner solar system. In fact, before BepiColombo, the only spacecraft to have visited Mercury were NASA’s Mariner 10 and MESSENGER missions.

Now, scientists hope to solve five mysteries with BepiColombo:

  1. Where did Mercury come from?
  2. Is there really water on Mercury?
  3. Is Mercury dead or alive?
  4. Why is Mercury so dark?
  5. Why does Mercury have a magnetic field?

To answer these questions, BepiColombo will spend at least one year orbiting Mercury. The mission will use its high-resolution instruments to learn about the mineralogical and elemental composition of Mercury’s surface. Plus, it will scan polar regions for ice. BepiColombo will look for anything that looks like it has changed on Mercury since MESSENGER visited 10 years earlier. And the two orbiters will travel through different areas of the planet’s magnetosphere to measure how it changes and interacts with the sun.

Bottom line: The BepiColombo mission has been maneuvering its way into orbit around Mercury for eight years. On September 3, it will release two orbiters in Mercury orbit.

Via ESA

Read more: Mercury images from final flyby of BepiColombo!

Read more: Mercury lives on? Strange streaks hint at active world

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Corona Australis is the sparkling Southern Crown

Star chart showing a Teapot-shaped group of stars and a curve of stars below labeled Corona Australis.
Corona Australis the Southern Crown can be challenging for northerners to spot. But it’s below the Teapot asterism in Sagittarius so look for it on late summer evenings. Chart via EarthSky.

Corona Australis the Southern Crown appears as an arc of sparkling stars. In fact, it’s one of the few constellations that somewhat resembles the object it’s named after. Ptolemy named Corona Australis in the 2nd century. Ancient Greeks saw this constellation as a wreath, while other civilizations saw a turtle or ostrich nest. Since it’s quite dim, you’ll want to be under dark skies to find it. But it’s relatively easy to pick out due to its location just south of major constellations. That’s because Corona Australis lies south of the Teapot asterism within Sagittarius.

The stars of Corona Australis

Just like its northern cousin, Corona Borealis, Corona Australis forms an arc. But the stars of the Southern Crown are so dim that its brightest stars are a mere magnitude 4.11. Beta Coronae Australis shines at the eastern edge of the constellation near the middle of the arc shape. The star lies 474 light-years distant.

The next star to the north in the arc is Alpha Coronae Australis, magnitude 4.10 and 125 light-years distant. Continuing in the same direction along the arc is a magnitude 4.23 star, 58 light-years away: Gamma Coronae Australis. Then 1.5 degrees west of this star is Epsilon Coronae Australis, magnitude 4.83 and 98 light-years away. Finally, the last notable star on this side of the arc is just over 3 degrees away, magnitude 5.11, Lambda Coronae Australis, at 202 light-years distant.

Heading the other direction from Beta is Delta Coronae Australis, a magnitude 4.57 star at a distance of 175 light-years. Next out is Zeta Coronae Australis, magnitude 4.74 and 184 light-years away. At the end of the crown is a double star system, Eta 1 and 2 Coronae Australis, at magnitude 5.46 and 347 light-years away, and magnitude 5.60 and 607 light-years distant, respectively.

Check out this lovely deep-sky image of nebulae in Corona Australis by Hector Rafael Vazquez Rispoli in Buenos Aires, Argentina.

White chart with stars in black, several forming the arc of Corona Australis.
The stars of Corona Australis. Image via IAU/ Sky and Telescope/ Wikimedia Commons.

Bottom line: Corona Australis is a dim constellation lying below the Teapot asterism of Sagittarius. Its sparkling, curving shape befits its name.

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Star chart showing a Teapot-shaped group of stars and a curve of stars below labeled Corona Australis.
Corona Australis the Southern Crown can be challenging for northerners to spot. But it’s below the Teapot asterism in Sagittarius so look for it on late summer evenings. Chart via EarthSky.

Corona Australis the Southern Crown appears as an arc of sparkling stars. In fact, it’s one of the few constellations that somewhat resembles the object it’s named after. Ptolemy named Corona Australis in the 2nd century. Ancient Greeks saw this constellation as a wreath, while other civilizations saw a turtle or ostrich nest. Since it’s quite dim, you’ll want to be under dark skies to find it. But it’s relatively easy to pick out due to its location just south of major constellations. That’s because Corona Australis lies south of the Teapot asterism within Sagittarius.

The stars of Corona Australis

Just like its northern cousin, Corona Borealis, Corona Australis forms an arc. But the stars of the Southern Crown are so dim that its brightest stars are a mere magnitude 4.11. Beta Coronae Australis shines at the eastern edge of the constellation near the middle of the arc shape. The star lies 474 light-years distant.

The next star to the north in the arc is Alpha Coronae Australis, magnitude 4.10 and 125 light-years distant. Continuing in the same direction along the arc is a magnitude 4.23 star, 58 light-years away: Gamma Coronae Australis. Then 1.5 degrees west of this star is Epsilon Coronae Australis, magnitude 4.83 and 98 light-years away. Finally, the last notable star on this side of the arc is just over 3 degrees away, magnitude 5.11, Lambda Coronae Australis, at 202 light-years distant.

Heading the other direction from Beta is Delta Coronae Australis, a magnitude 4.57 star at a distance of 175 light-years. Next out is Zeta Coronae Australis, magnitude 4.74 and 184 light-years away. At the end of the crown is a double star system, Eta 1 and 2 Coronae Australis, at magnitude 5.46 and 347 light-years away, and magnitude 5.60 and 607 light-years distant, respectively.

Check out this lovely deep-sky image of nebulae in Corona Australis by Hector Rafael Vazquez Rispoli in Buenos Aires, Argentina.

White chart with stars in black, several forming the arc of Corona Australis.
The stars of Corona Australis. Image via IAU/ Sky and Telescope/ Wikimedia Commons.

Bottom line: Corona Australis is a dim constellation lying below the Teapot asterism of Sagittarius. Its sparkling, curving shape befits its name.

The post Corona Australis is the sparkling Southern Crown first appeared on EarthSky.



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Giant mega-Earth is 23 times more massive than Earth

Giant mega-Earth: Large, rocky planet similar to Earth with the Milky Way in the background.
View larger. | Artist’s concept of a giant mega-Earth. The newly discovered mega-Earth GJ 523b is 23.5 times the mass of Earth and 2.5 times its size. Image via Pablo Carlos Budassi/ Wikimedia Commons.
  • Astronomers have confirmed an unusual planet called GJ 523b. It belongs to a rare group of worlds known as mega-Earths.
  • The planet is only about 2.5 times as wide as Earth but has more than 23 times its mass. That makes it unusually dense.
  • Scientists don’t understand how it formed this way. A planet this massive would normally be expected to have a thick atmosphere of hydrogen and helium.

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Giant mega-Earth is 23 times Earth’s mass

On July 23, 2026, astronomers at the University of Wisconsin–Madison announced the confirmation of GJ 523b, an unusually dense mega-Earth first detected in data from NASA’s TESS telescope.

Rocky exoplanets called super-Earths are quite common in our galaxy. These worlds are larger and more massive than Earth, but smaller than Neptune. But now astronomers have found an even more massive planets called  mega-Earths. Fewer mega-Earths have been discovered so far than super-Earths, but they do exist. This newest one – GJ 523b – might be the best example known so far. It is a whopping 23 times as massive as Earth.

GJ 523b is 2.5 times the diameter of Earth. Some super-Earths can be that large, but the extreme mass is unusual. And the planet is estimated to be only 170 million years old. That’s in contrast to Earth’s age of 4.54 billion years. So the GJ 523 system is much younger than our own solar system. The planet orbits a orange dwarf star.

Thomas Beatty at University of Wisconsin-Madison said:

People have been using the phrase ‘Mega-Earth’ for more than a decade, but we’ve never had a planet that let us say concretely what one is. GJ 523b finally does. What is also striking is that nailing down the definition of a Mega-Earth isn’t something us astronomers can really do by ourselves: We need geologists who understand how iron and rock behave at pressures no laboratory on Earth can reach, and atmospheric scientists who can tell us how much of what we measured is rock at all.

The new paper is still undergoing peer-review but was first published on the preprint server arXiv on March 25, 2026.

Diagram comparing the radii and densities of confirmed exoplanets. Mega-Earths appear in red, while the arrows mark the authors’ proposed definition of the class. GJ 523b is among the unusually dense planets in this region. Image via Kroft et al./ arXiv.

TESS makes a surprising discovery

Astronomers first used NASA’s TESS space telescope first detected GJ 523b as it passed in front of its star, causing a tiny dip in the star’s brightness. These transits allowed astronomers to estimate the planet’s size.

Lead author Max Kroft at University of Wisconsin-Madison said:

There’s this periodic dipping of the star’s light. We think that’s a planet passing in front of the star and transiting. It’s blocking some of the light from the star, and the star gets dimmer.

We picked out this planet based on what we thought its size and temperature were. A bigger planet makes a bigger dip, so we get an idea of the size, and based on how often that dip happens, we get the distance of its orbit and we can use that to estimate the temperature of the exoplanet.

The researchers then used the NEID spectrograph and data on the WIYN 3.5-meter telescope to determine it’s mass. High-resolution imaging from Gemini North and Palomarto were used to further study GJ 523b. They found some surprises. It was more massive than most rocky planets of its size; 23.5 times more massive than Earth and 2.5 times the diameter of Earth, or 60% the size of Neptune. As Kroft noted, this was an unexpected finding:

This isn’t what we expected at all. Dense planets like this aren’t uncommon, but they’re usually small rocky planets similar to Earth or Mercury. This planet is 2.5 times bigger than the Earth.

Man with wide smile, eyeglasses and very curly hair.
Max Kroft at University of Wisconsin-Madison led the new study about GJ 523b. Image via University of Wisconsin-Madison.

How did GJ 523b form this way?

So how did GJ 523b end up being so extremely dense and massive? Why didn’t the planet develop a massive hydrogen atmosphere?

In the words of Kroft, the discovery was:

a real curveball.

During planet formation, worlds with cores around 10 to 20 times Earth’s mass are generally expected to pull in thick atmospheres of hydrogen and helium. GJ 523b is massive enough for this to happen, yet it appears to contain very little gas.

The study found that ordinary heating from the star probably could not remove enough gas. Giant impacts, an extremely close passage by the star or forming without much gas are possible explanations.

Kroft also notes that the planet would still have been hot from its formation. Too hot to hold onto its atmosphere. Krofft explained:

It kind of blows away. A planet can’t hold on to its atmosphere if it’s really hot, and so you could be left with this big glob of rock made by these two planets with very little atmosphere.

The planet’s orbit offers another clue.

The researchers estimate that it is tilted by at least 71 degrees relative to the rotation of its star. This unusual alignment suggests that GJ 523b might have migrated from elsewhere in the system or experienced a turbulent event early in its history.

More planets like GJ 523b

The researchers are hopeful that astronomers will find more planets like GJ 523b. There are over 6,000 confirmed exoplanets already found, and thousands more candidates. Kroft said:

It’s hard to infer things about planet formation in general from a sample size of one. We’re not going to get to 10,000 of these over-dense planets, but if we can get to 20 or 30, maybe some trends might pop out, where maybe the heaviest ones have shorter orbital periods, or they tend not to have companion planets.

Bottom line: Astronomers discover mega-Earth, GJ 523b, has 23.5 times Earth’s mass but only 2.5 times its radius. Its extreme density, apparent lack of a thick gas atmosphere and highly tilted orbit challenge standard ideas about how massive planets form.

Source: GJ 523b is a Massive, 170 Myr-old Mega-Earth, Likely on a Polar Orbit

Via University of Wisconsin-Madison

Via Phys.org

Read more: Kepler-10 star system has a mega-Earth!

Read more: Exoplanet art lets you visualize alien worlds

The post Giant mega-Earth is 23 times more massive than Earth first appeared on EarthSky.



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Giant mega-Earth: Large, rocky planet similar to Earth with the Milky Way in the background.
View larger. | Artist’s concept of a giant mega-Earth. The newly discovered mega-Earth GJ 523b is 23.5 times the mass of Earth and 2.5 times its size. Image via Pablo Carlos Budassi/ Wikimedia Commons.
  • Astronomers have confirmed an unusual planet called GJ 523b. It belongs to a rare group of worlds known as mega-Earths.
  • The planet is only about 2.5 times as wide as Earth but has more than 23 times its mass. That makes it unusually dense.
  • Scientists don’t understand how it formed this way. A planet this massive would normally be expected to have a thick atmosphere of hydrogen and helium.

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Giant mega-Earth is 23 times Earth’s mass

On July 23, 2026, astronomers at the University of Wisconsin–Madison announced the confirmation of GJ 523b, an unusually dense mega-Earth first detected in data from NASA’s TESS telescope.

Rocky exoplanets called super-Earths are quite common in our galaxy. These worlds are larger and more massive than Earth, but smaller than Neptune. But now astronomers have found an even more massive planets called  mega-Earths. Fewer mega-Earths have been discovered so far than super-Earths, but they do exist. This newest one – GJ 523b – might be the best example known so far. It is a whopping 23 times as massive as Earth.

GJ 523b is 2.5 times the diameter of Earth. Some super-Earths can be that large, but the extreme mass is unusual. And the planet is estimated to be only 170 million years old. That’s in contrast to Earth’s age of 4.54 billion years. So the GJ 523 system is much younger than our own solar system. The planet orbits a orange dwarf star.

Thomas Beatty at University of Wisconsin-Madison said:

People have been using the phrase ‘Mega-Earth’ for more than a decade, but we’ve never had a planet that let us say concretely what one is. GJ 523b finally does. What is also striking is that nailing down the definition of a Mega-Earth isn’t something us astronomers can really do by ourselves: We need geologists who understand how iron and rock behave at pressures no laboratory on Earth can reach, and atmospheric scientists who can tell us how much of what we measured is rock at all.

The new paper is still undergoing peer-review but was first published on the preprint server arXiv on March 25, 2026.

Diagram comparing the radii and densities of confirmed exoplanets. Mega-Earths appear in red, while the arrows mark the authors’ proposed definition of the class. GJ 523b is among the unusually dense planets in this region. Image via Kroft et al./ arXiv.

TESS makes a surprising discovery

Astronomers first used NASA’s TESS space telescope first detected GJ 523b as it passed in front of its star, causing a tiny dip in the star’s brightness. These transits allowed astronomers to estimate the planet’s size.

Lead author Max Kroft at University of Wisconsin-Madison said:

There’s this periodic dipping of the star’s light. We think that’s a planet passing in front of the star and transiting. It’s blocking some of the light from the star, and the star gets dimmer.

We picked out this planet based on what we thought its size and temperature were. A bigger planet makes a bigger dip, so we get an idea of the size, and based on how often that dip happens, we get the distance of its orbit and we can use that to estimate the temperature of the exoplanet.

The researchers then used the NEID spectrograph and data on the WIYN 3.5-meter telescope to determine it’s mass. High-resolution imaging from Gemini North and Palomarto were used to further study GJ 523b. They found some surprises. It was more massive than most rocky planets of its size; 23.5 times more massive than Earth and 2.5 times the diameter of Earth, or 60% the size of Neptune. As Kroft noted, this was an unexpected finding:

This isn’t what we expected at all. Dense planets like this aren’t uncommon, but they’re usually small rocky planets similar to Earth or Mercury. This planet is 2.5 times bigger than the Earth.

Man with wide smile, eyeglasses and very curly hair.
Max Kroft at University of Wisconsin-Madison led the new study about GJ 523b. Image via University of Wisconsin-Madison.

How did GJ 523b form this way?

So how did GJ 523b end up being so extremely dense and massive? Why didn’t the planet develop a massive hydrogen atmosphere?

In the words of Kroft, the discovery was:

a real curveball.

During planet formation, worlds with cores around 10 to 20 times Earth’s mass are generally expected to pull in thick atmospheres of hydrogen and helium. GJ 523b is massive enough for this to happen, yet it appears to contain very little gas.

The study found that ordinary heating from the star probably could not remove enough gas. Giant impacts, an extremely close passage by the star or forming without much gas are possible explanations.

Kroft also notes that the planet would still have been hot from its formation. Too hot to hold onto its atmosphere. Krofft explained:

It kind of blows away. A planet can’t hold on to its atmosphere if it’s really hot, and so you could be left with this big glob of rock made by these two planets with very little atmosphere.

The planet’s orbit offers another clue.

The researchers estimate that it is tilted by at least 71 degrees relative to the rotation of its star. This unusual alignment suggests that GJ 523b might have migrated from elsewhere in the system or experienced a turbulent event early in its history.

More planets like GJ 523b

The researchers are hopeful that astronomers will find more planets like GJ 523b. There are over 6,000 confirmed exoplanets already found, and thousands more candidates. Kroft said:

It’s hard to infer things about planet formation in general from a sample size of one. We’re not going to get to 10,000 of these over-dense planets, but if we can get to 20 or 30, maybe some trends might pop out, where maybe the heaviest ones have shorter orbital periods, or they tend not to have companion planets.

Bottom line: Astronomers discover mega-Earth, GJ 523b, has 23.5 times Earth’s mass but only 2.5 times its radius. Its extreme density, apparent lack of a thick gas atmosphere and highly tilted orbit challenge standard ideas about how massive planets form.

Source: GJ 523b is a Massive, 170 Myr-old Mega-Earth, Likely on a Polar Orbit

Via University of Wisconsin-Madison

Via Phys.org

Read more: Kepler-10 star system has a mega-Earth!

Read more: Exoplanet art lets you visualize alien worlds

The post Giant mega-Earth is 23 times more massive than Earth first appeared on EarthSky.



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