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Falcon rocket will hit the moon on August 5

Back on January 15, 2025, a Falcon 9 rocket launched two missions toward the moon: Blue Ghost and Hakuto-R. After the upper stage of the Falcon 9 rocket completed its boosting mission, it became just another piece of space junk. But now, says Bill Gray, a prolific tracker of near-Earth objects, the Falcon 9 is on a collision course with the moon.

Gray estimates the upper stage will hit the moon at 1:44 a.m. CDT (6:44 UTC) on August 5, 2026. As Gray said:

It doesn’t present any danger to anyone, though it does highlight a certain carelessness about how leftover space hardware (space junk) is disposed of.

Will we be able to see the impact?

The moon will be close to last quarter phase on August 5, 2026. By 1:44 a.m. CDT, those in the Central Time Zone will be able to see the moon, as it will have already risen in the east. Saturn will be nearby. Check Stellarium to see if the moon will be above the horizon at the time of impact if you’re further west. The timing will favor people in the eastern half of the U.S. and Canada, plus much of South America.

So where will the rocket hit? Right now, Gray said he estimates the impact will occur near the edge, or limb, of the moon, close to the Einstein crater.

However, the chances are we won’t be able to see the impact from Earth. Darn. Although the Einstein crater should (barely) be visible, the impact will likely be too small to see from so great a distance. However, after the impact, NASA’s Lunar Reconnaissance Orbiter might be able to get an image of the resulting crater. It’s happened before.

Previous lunar impact

Back in 2022, Bill Gray also predicted a rocket impact with the moon. There was a little confusion about where the rocket came from, but the space junk did indeed hit the moon on March 4, 2022. And it left a mark, too. NASA’s Lunar Reconnaissance Orbiter took an image of the aftermath.

A speeding object

Gray estimates the space junk will hit the moon at about 2.43 kilometers (1.51 miles) a second. That equates to 5,400 miles (8,700 kilometers) an hour. Because the moon has no real atmosphere, there will be nothing to slow it down.

Tracking the Falcon 9 upper stage

There have been hundreds of Falcon 9 launches. Usually, the spent rocket bodies orbit closely to Earth and eventually reenter our atmosphere. But some have gone on to orbit the sun.

This upper stage rocket has spent most of its time farther out than average, around the distance of the moon. Asteroid surveys pick up objects like this as they scan for dangerous space rocks. As Gray said:

The asteroid surveys would actually prefer not to observe space junk. Time spent observing junk is time not spent finding rocks. But both the rocks and the high-altitude space junk are slowly moving points of light in their images; they aren’t easy to distinguish. So the asteroid surveys find this sort of junk whether they want to or not.

Gray provides software tools for astronomers that help them distinguish between space rocks and space junk. He also computes orbits for high-orbiting objects the military doesn’t track. And he’s been tracking this piece of space junk for months. He’s known since September 2025 that the upper stage was likely on a collision course with the moon. And as he told EarthSky, he wasn’t surprised:

I’ve been checking for such possible impacts for about 20 years, ever since we started having many large bits of junk in orbits that could hit the moon. In a way, the only real surprise is that only two objects have hit the moon.

Rocket will hit the moon despite tiny pushes from sunlight

Over the past months he’s continued to track the object. The reason it can change course a tiny bit is due to the gentle push of sunlight on objects. And that little bit of push is tricky to track. As Gray said:

As an object tumbles, it may catch more or less sunlight, and may reflect some of it sideways.

But, as Gray told EarthSky:

I was reasonably sure a month or two later, but was in no rush to say anything about it. I figured I’d wait until the impact location was well established. So it was something of a gradual process, with no ‘Aha! It’s gonna hit!’ moment.

Not a lot of tracking farther from Earth

Gray told EarthSky:

I am an astronomer working under contract with both asteroid and artificial object observers. I started out doing this for natural objects (asteroids, comets, moons of other planets) about 30 years ago. A few years later, the asteroid surveys started to notice the occasional artificial object and asked me if I could find orbits for them as well.

And as Gray explains on his website, various countries carefully track objects in low-Earth orbit because there are so many pieces of debris with risks of collision with military and science satellites. Farther from Earth, there is less tracking. Or, as Gray said:

Generally speaking, high-altitude junk goes ignored. (Except, it appears, by me.)

Gray works with asteroid hunters. As he said:

My ‘day work’ is for the asteroid-hunting community … Most artificial objects are close to the Earth and move fast enough that there is no risk of mistaking them for an asteroid. But there are about a dozen ‘high-flying’ objects that can move slowly enough to look like a rock, at least briefly. For about 15 or 20 years now, I’ve taken these observations and computed orbits. Then, when the surveys find such objects, they can fairly quickly say ‘Never mind; it’s not a rock; it’s just another nuisance artificial object,’ and go back to looking for actual rocks.

Bottom line: A Falcon 9 rocket will hit the moon on August 5, 2026. How fast will it be going? Will we be able to see it? Answers here.

The post Falcon rocket will hit the moon on August 5 first appeared on EarthSky.

ESA originally published this article on April 21, 2026. Edits by EarthSky.

Euclid Space Warps: Help spot galaxies bending spacetime!

With the launch of Space Warps, a new citizen science project, you can now join in the search to find galaxies that are bending the very fabric of the universe.

Hosted on the Zooniverse platform, this project sees members of the public search through never-before-seen images captured by the Euclid space telescope to find rare and elusive strong gravitational lenses. The project aims to shine a light on dark matter in galaxies and provide clues about mysterious dark energy.

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Gravity warps spacetime

Warps in spacetime do not only show up in science fiction movies like Interstellar. In real life, we can see the warping effect that gravity has on spacetime in the form of gravitational lensing.

The enormous gravity of a massive object – such as a galaxy or cluster of galaxies – distorts the shape of spacetime and can bend the light rays coming from a distant galaxy behind. By warping spacetime, the foreground galaxy acts like a magnifying glass.

Light from the background object that would be obscured doesn’t travel in a straight line anymore. Instead, it curves around the intervening mass. That often produces multiple images, stretched arcs, or even a complete ring known as an “Einstein ring,” like the one recently discovered by Euclid.

ESA’s Euclid telescope launched in July 2023 and is revolutionizing the studies of strong gravitational lensing by providing very sensitive imaging over large swaths of the sky. This is exactly what is needed to identify rare gravitational lenses.

In March 2025, 500 galaxy-galaxy strong lenses were found nestled in just the first 0.04% of Euclid data, most of them previously unknown. This pioneering catalog was created thanks to the combined effort from citizen scientists, artificial intelligence and researchers.

Spot gravitational lenses with Space Warps

As Euclid continues its survey, sending around 100 gigabytes of data back to Earth every day, ESA and the Euclid Consortium once again need help from citizen scientists to identify strong gravitational lenses in a large data set.

For this, the Space Warps team has launched a citizen science project based on new Euclid images, which will be part of the future Euclid Data Release 1. This data is not public yet. So by participating in this new citizen science project, you can get an early glimpse of Euclid’s new images.

For this project, you will be inspecting new high quality imaging data from Euclid in which many previously unknown strong lenses are hiding. About 300,000 images pre-selected by AI algorithms will be shown, fine-tuned with the results from the initial citizen-science Euclid strong lens search.

These are the highest-ranked candidates from a whopping 72 million galaxies from Data Release 1 that were classified by the AI algorithms. Scientists expect that this exquisite high-quality data will reveal more than 10,000 new lenses.

What we can learn from strong lenses

The Euclid mission explores how the universe has expanded and how its structure has changed through cosmic history. It does so using mainly two methods: weak gravitational lensing and a phenomenon known as baryonic acoustic oscillations. From this, scientists can learn more about the role of gravity and the nature of dark matter and dark energy.

Strong gravitational lenses can also provide insights into these central questions. For example, strong lensing features can “weigh” individual galaxies and clusters of galaxies. This reveals the total matter (whether dark or light) and traces the distribution of dark matter.

By studying strong lenses across cosmic time, scientists can trace the expansion of the universe and its apparent acceleration. This will provide additional insight into the role of dark energy.

Aprajita Verma, Space Warps’ co-founder and project lead at the University of Oxford in the U.K., said:

We’ve already seen the success of combining AI with visual inspection by citizen volunteers and scientists on Space Warps, efficiently finding hundreds of high-probability lens candidates in an initial small Euclid search in 2024.

In this brand-new Data Release 1 data, 30 times larger than the initial search and together with our improved AI algorithms, we are expecting to find more than 10,000 high quality lens candidates. This is more than four times the number of lenses than we have been able to find since the first gravitational lens was discovered nearly 50 years ago.

We can’t wait to see what we will find within this unprecedented dataset. Join us on Space Warps to take part in this exciting search!

Bottom line: New citizen science project Space Warps lets you study new Euclid space telescope data to find galaxies bending the fabric of the universe.

Via ESA

Read more: New Euclid images reveal hidden gravitational lenses

The post Euclid Space Warps: Help spot galaxies bending spacetime! first appeared on EarthSky.

• For years, evidence has grown for an ancient lake once existing in Gale crater on Mars. Now NASA’s Curiosity rover has found yet more clues.
• The rover found the highest concentrations of iron, manganese and zinc ever seen in one place on Mars. The metal minerals are in well-preserved ripples in rocks.
• The chemistry and location of the minerals strongly support the presence of a former shallow lake at this location.

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Ancient lake on Mars

Scientists have long thought that there was once a lake, or series of lakes, in Gale crater, where the Curiosity rover has been exploring since 2012. Now, Curiosity has found even more evidence for that ancient lake.

Researchers led by the Los Alamos National Laboratory said on April 21, 2026, that the rover has discovered the highest concentration of iron, manganese and zinc ever found together on Mars. This deposit of metals is similar to deposits formed by chemical reactions in lakes on Earth. Plus, Curiosity found the metals within ripples in rocks. It seems an ancient shallow lake produced these ripples, and deposited these metals within them.

Intriguingly, on Earth, deposits like this are almost always inhabited by microbial life. This isn’t proof of ancient life on Mars, but the similarities are striking.

The researchers published their peer-reviewed findings in the journal JGR Planets on April 13, 2026.

Curiosity found a treasure trove of minerals

Curiosity found the minerals in late 2022 in a dark section of exposed rock called the Amapari Marker Band. Using its Chemistry & Camera (ChemCam) instrument, the rover detected the iron, manganese and zinc in preserved ripples in the rocks.

Patrick Gasda, the lead author of the study, explained:

The metals were found in preserved ripples, which is the clearest evidence we have that a lake was present in Gale crater.

Evidence for past life?

On Earth, some microbes use these very same metal minerals as food and energy sources. The mineral deposits by themselves don’t prove past microbial life. But they do show that conditions were suitable for life on Mars to thrive, if it ever existed.

Gasda said:

Given the exciting astrobiological implications raised by the Amapari Marker Band, these types of materials should be prioritized for future Curiosity chemistry analysis.

Interestingly, the deposits are high up on the slopes of Mount Sharp. As the former lake dried out over time, the remaining pockets of water could still have supported life.

The paper explains:

What is most surprising about this discovery is that the rover was exploring rocks that were deposited during this time period on Mars where the climate was changing from wet to dry. The rocks just below the layers with preserved ripples are indicative of drier conditions persisting on the surface of Mars. This shallow lake formed as at least part of a deposit that spans most of the sedimentary rock mound within the crater, that became deeper over time. A deep lake such as this one can have chemical gradients and would have favorable conditions for life.

Zapping rocks with a laser

Wondering how Curiosity analyzes the rocks? It zaps them with a laser. The technique, called laser-induced breakdown spectroscopy, works by vaporizing a small portion of the sample into plasma, or an incredibly hot cloud of exited, broken-apart atoms. ChemCam then analyses the light coming from this cloud to determine what elements are in the rock. In this case, it discovered a collection of metals that, on Earth, are found together in lakes.

Most diverse organic molecules ever seen on Mars

Just a few days ago, NASA also reported that Curiosity has found the most diverse collection of organic molecules ever seen on Mars. Overall, it found 21 types of organics in a rock called Mary Anning. Seven of those had never been seen before, until now.

And last year, Curiosity also discovered the most complex organic molecules ever found on Mars so far. Scientists think they are the remains of fatty acids.

‘Dragon scales’ in Gale crater

Curiosity also recently found some unusual dragon scales formations in Gale crater. The rover has seen similar ones before, but not this many in one location. This is the largest amount of these scales ever seen so far. Curiosity came across them near Antofagasta, a relatively young, 33-foot (10-meter) wide impact crater located on the slopes of Mount Sharp.

Abigail Fraeman, a planetary scientist at the Jet Propulsion Laboratory, said:

Many of the rocks we’ve driven over have these incredible textures, thousands of honeycomb-shaped polygons crisscross their surface. We’ve seen polygon-patterned rocks like these before, but they didn’t seem quite this dramatically abundant.

Scientists don’t yet know exactly how these features formed. But similar ones seen before were most likely created by drying mud. So they could have formed as the lake or other small bodies of water dried up billions of years ago in a wet-dry cycle.

Bottom line: NASA’s Curiosity rover has found yet more evidence for an ancient lake on Mars. Metallic minerals in preserved rock ripples provide the clues.

Source: Amapari Marker Band Metal-Enrichments: Potential Mechanisms and Implications for Surface and Subsurface Water and Weathering in Gale Crater

Via Los Alamos National Laboratory

Read more: New organics on Mars raise questions about ancient life

Read more: Curiosity rover spots signs of ancient megafloods on Mars

The post Ancient lake on Mars? Rover finds strong new evidence first appeared on EarthSky.

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Jan Oort: Father of the Oort Cloud

Jan Hendrick Oort was born on today’s date – April 28, 1900 – in Franeker, Netherlands. We know his name today because he theorized the existence of the Oort Cloud, a vast comet cloud in the outermost reaches of our Solar System.

As early as 1932, Oort also became one of the first to use the term dark matter.

And, when it came to expertise about our home galaxy, the Milky Way, few astronomers in the 20th century were more knowledgeable than Jan Oort.

Jan Oort and the Oort Cloud

1950 was a key year for Oort. That was the year he proposed the theory of the Oort Cloud.

The Oort Cloud is also known as the Öpik-Oort Cloud in honor of Ernst Öpik, an Estonian astronomer. Öpik had independently postulated the existence of a cloud of comets encircling our Solar System in 1932.

The theory of this comet reservoir stemmed from astronomers’ observations. They noticed that two types of comets travel into the inner Solar System to round the sun that binds them in orbit. Some have relatively short orbital periods, on the order of about 200 years or less. And some comets require much longer, thousands of years, to orbit the sun once.

But where do these comets come from? Oort proposed a reservoir of comets at the outer limits of our Solar System. He said that long-period comets are sometimes knocked from their very distant orbits (perhaps by passing stars) to orbits that bring them near our sun.

If it exists, this cloud of comets – the Oort Cloud – contains material leftover from the formation of our Solar System, 4.5 billion years ago. The comets within it lie as close as about 2,000 times up to about 100,000 times the Earth-sun distance. That’s a distance of up to 93 trillion miles (150 trillion km) away.

The Oort Cloud of comets is not an observed fact. It’s still a theory. But it’s a well-accepted theory by astronomers that has stood the test of time. And it’s thought to explain the origin of long-period comets such as Comet Hale-Bopp.

Jan Oort solved the comet puzzle

Prior to Oort’s work on the Oort Cloud, astronomers wondered for hundreds of years (or thousands of years, if you count history’s earliest watchers of the skies) where comets originate. Astronomers in the 20th century knew that comets collide with other celestial bodies. They knew comets vaporize when they pass too near the sun. And sometimes those close encounters eject them from our Solar System.

And yet there are always new comets coming to our part of the Solar System. Why? Where do they come from?

The Oort Cloud answers this paradox of comets that seem to appear out of nowhere.

In school, he followed his passions

Oort was one of five children. His father, Abraham Hendrikus Oort, was a psychiatrist. Oort’s parents always encouraged him to follow his passions. And so he decided to study physics at the University of Groningen in 1917.

Attending the lectures of astronomer Jacobus Kapteyn was a turning point for Oort. In fact, Kapteyn’s research greatly inspired him and he switched to studying astronomy.

Later, in 1924, Leiden Observatory welcomed Oort, where he began studying high-velocity stars. Two years later, he defended his doctoral thesis on that subject. This was, additionally, four years after the death of his friend and mentor, Professor Kapteyn.

Jan Oort’s early work

In 1926, astronomer Bertil Lindblad explained the stellar motion properties studied by Kapteyn to be the result of the rotation of the Milky Way. He explained it by proposing that stars closer to the center of the galaxy revolve around the galaxy’s center faster than stars farther away from the center. Subsequently, Jan Oort successfully proved and modified Lindblad’s theory in 1927 after observing the velocities of many stars.

During Oort’s studies of star motions in 1932, he noticed that many stars move faster than expected, given their location within the Milky Way. With this in mind, he then used the term dark matter – not as we use it today – but in the sense of ordinary stars that are either dim (or dark) or hidden from us behind other stars.

Oort continued developing the Lindblad theory. It eventually came to be known as the Lindblad-Oort theory because of his contributions.

Later, Oort became a professor at the University of Leiden in 1935. Among other major accomplishments, the young professor determined that our sun is some 26,000 light-years from the center of our Milky Way galaxy. This is still the number we use today. He also calculated that the sun orbits around the center of the galaxy once every 225 million years.

In 1945, the Observatory of Leiden appointed Oort as their Director.

He maintained this position until 1970.

Oort died in 1992, at 92 years old. But his contributions to astronomy live on.

Bottom line: Dutch astronomer Jan Oort was born on April 28, 1900. He visualized a vast reservoir of icy comets on the outskirts of our Solar System, which now bears his name.

Read more: Could there be a captured planet hiding in the Oort Cloud?

The post Jan Oort birthday and discovery of the Oort Cloud first appeared on EarthSky.

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• Interstellar comet 3I/ATLAS is only the 3rd known interstellar object. It came from another star system.
• Astronomers just learned it contains 30 times more “heavy water” than our solar system’s comets. Our comets consist of ordinary H2O, with ordinary hydrogen atoms containing just one proton and no neutron. 3I/ATLAS contains deuterium (one neutron and one proton).
• This finding is clue to where 3I/ATLAS formed. It suggests its home star formed in a much colder environment than the one that created our sun.

Comet 3I/ATLAS comes from afar

In July 2025, astronomers spied an object at about three times Mars’ distance from our sun. And, once they had tracked its path through space, they knew it originated in another star system. 3I/ATLAS, as it’s come to be called, is only the 3rd such interstellar object known. We don’t know where or how it escaped that distant star system in order to pass through our solar system. But astronomers said this month they have new clues about its past. They said it formed in an environment much colder than the one that created our sun and planets. 

How do we know? Radio telescope observations detected high levels of “heavy” water in 3I/ATLAS. That’s a form of water containing the element deuterium. And it’s a sign of cold conditions in the star-forming molecular cloud that gave birth to 3I/ATLAS’ star. This cloud must have been colder than conditions that formed our sun.

It’s an intriguing finding because it shows that star formation can occur under different physical and chemical conditions than those that created our solar system.

Luis Salazar Manzano is the lead author of a paper on this study. He said, in a statement:

Our new observations show that the conditions that led to the formation of our solar system are much different from how planetary systems evolved in different parts of our galaxy.

The researchers published their findings in the peer-reviewed journal Nature Astronomy on April 23, 2026.

It’s a comet, but different from those in our solar system

Astronomers sometimes refer to comets as “dirty snowballs” because they contain a lot of water. They’re icy remnants from the formation of our solar system, 4.6 billion years ago. Therefore, comets contain a record of the early conditions from which our sun and planets emerged.

Comets in our solar system come from distant reservoirs of icy objects called the Kuiper Belt and Oort Cloud. Sometimes, gravitational perturbations jostle some of these objects from their stable orbits. As a result, they fall into highly elliptical orbits that bring them close to the sun. Near the sun, sunlight heats these objects causing the release of gas and dust that form a tail.

It’s one of 3 known interstellar visitors

Astronomers know of three objects that are interstellar visitors. Besides 3I/ATLAS, the only other known interstellar comet is 2I/Borisov, that appeared in 2019. And there’s 1I/Oumuamua, not a comet but a cigar-shaped object that passed through in 2017.

3I/ATLAS and 2I/Borisov most likely formed in the far outskirts of their home systems, just like comets in our solar system. Therefore, they too contain a record of the early environment that formed their stellar systems.

3I/ATLAS contains “heavy water”

Water, chemically called H20, is made of two hydrogen atoms and one oxygen atom. Hydrogen, which formed shortly after the Big Bang, has one proton in its nucleus. However, the Big Bang also created another type of hydrogen, but in much smaller quantities. It’s called deuterium, and it has one neutron and one proton in its nucleus.

Most water on Earth contains hydrogen but there is a small amount of naturally occurring water containing deuterium, called deuterated water or heavy water. (Its chemical name is HDO, one atom each of hydrogen, deuterium, and oxygen.)

When astronomers looked at 3I/ATLAS with radio telescopes, they discovered, to their surprise, that it had a lot more deuterated water compared to comets in our solar system.

Salazar Manzano commented:

The amount of deuterium with respect to ordinary hydrogen in water is higher than anything we’ve seen before in other planetary systems and planetary comets.

Comets in our solar system have one molecule of deuterated water for every 10,000 molecules of ordinary water. However, in 3I/ATLAS, that ratio was 30 times higher. And compared to water in our oceans, that ratio was 40 times higher.

3I/ATLAS must have formed under different conditions

Molecular clouds are where stars form. There is a higher ratio of deuterium to hydrogen in cold molecular clouds, compared to the ratio created in the Big Bang. That’s due to a complex series of chemical reactions.

Molecules containing deuterium instead of hydrogen are more stable at low temperatures. So when molecular interactions replace hydrogen with deuterium in water molecules, that’s called “deuterated.” Those water molecules sticking to dust grains form deuterated ice, which is more likely to last in a colder environment.

This new study shows that conditions under which stars are created can vary. In 3I/ATLAS, the higher ratio of deuterated water suggests that the environment where its star formed was colder and had lower levels of radiation, compared to the environment in which our sun was born.

Salazar Manzano said:

The chemical processes that lead to the enhancement of deuterated water are really sensitive to temperature and usually require environments colder than about 30 Kelvin, or about minus 406 degrees Fahrenheit.

Radio telescopes have been observing 3I/ATLAS

For this study of 3I/ATLAS, the researchers used radio telescopes at the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

The radio telescopes detected the distinct signature of deuterated water in the comet. But the telescopes could not directly detect ordinary water. Therefore, the researchers used a mathematical model to determine the amount of ordinary water present based on methanol measurements.

They observed the comet on November 4, 2025, just six days after its closest approach to the sun. Teresa Paneque Carreño, a paper co-author, noted:

Most instruments can’t point toward the sun, but radio telescopes like ALMA can. We were able to observe the comet within days after perihelion, just as it peeked out from its transit behind the sun. This gave us a constraint on these molecules that’s not possible using other instruments.

She also added:

Each interstellar comet brings a little bit of its history, its fossils, from elsewhere. We don’t know exactly where, but with instruments like ALMA we can begin to understand the conditions of that place and compare them to our own.

Bottom line: The chemistry of water in interstellar comet 3I/ATLAS indicates that its home star formed in colder conditions compared to that of our sun.

Source: Water D/H in 3I/ATLAS as a probe of formation conditions in another planetary system

Via Atacama Large Millimeter/submillimeter Array (ALMA)

Via University of Michigan

Read more:
5 insights on interstellar comet 3I/ATLAS from ESA’s Juice mission
Surprise! Interstellar comet 3I/ATLAS bursting with alcohol
Is the 3rd interstellar visitor – 3I/ATLAS – an alien probe?

The post Interstellar comet 3I/ATLAS born in a cold environment first appeared on EarthSky.

• NASA’s Curiosity rover has found the most diverse collection of organic molecules ever seen on Mars.
• The organics include seven new carbon-bearing molecules. Such molecules on Earth form the basis of all biological processes. They make up the structures of cells and tissues, participate in chemical reactions that sustain life, and store and transmit genetic information.
• The new organics add to the evidence for Mars’ life now or in the past. Mars apparently had (or has) the right chemistry to support life.

Most diverse organic molecules on Mars

There are two active rovers on Mars now. And both Curiosity and Perseverance have found an abundance of Martian organic molecules in recent years. These are molecules containing carbon, capable of forming long chains and complex rings. On Earth, they’re related to life. And now Curiosity has identified the most diverse collection of organic molecules yet seen on Mars. They include organics not seen before on the red planet. 

NASA said on April 21, 2026, that pinpointing them took years of lab work, both in Curiosity’s onboard laboratory and in comparison studies back on Earth. Overall, the rover found 21 carbon-bearing molecules in a rock it first sampled in 2020. Seven of those molecules are new discoveries on Mars.

It isn’t known if any of the organics are related to ancient life. But the scientists said they add to the evidence that Mars had the right chemistry to support life.

Notably, rocks that had been exposed to harsh ultraviolet radiation for billions of years were still able to preserve the organics.

The researchers published the tantalizing peer-reviewed results in Nature Communications on April 21, 2026.

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NASA’s Curiosity Finds Organic Molecules Never Seen Before on Marswww.nasa.gov/missions/mar…

— HiRISE Beautiful Mars (NASA) (@uahirise.bsky.social) 2026-04-21T21:25:34.798Z

Mary Anning 3

Curiosity found the diverse collection of organics in a drill sample nicknamed Mary Anning 3. It’s one of three holes that the rover drilled in the same rock. The other two holes are named Mary Anning and Groken. (A nearby spot named Mary Anning 2 is one that Curiosity never drilled.) Mary Anning is the name of an early 19th-century English fossil collector and paleontologist.

The rock is on a part of Mount Sharp in Gale Crater where lakes and flowing rivers once existed. The area is rich in clay minerals, which are ideal for preserving organic molecules.

The most interesting organics

One of the most interesting organic molecules researchers found is nitrogen heterocycle. It’s a ring of carbon atoms including nitrogen. These molecules are predecessors to both DNA and RNA. Lead author Amy Williams at the University of Florida in Gainesville said:

That detection is pretty profound because these structures can be chemical precursors to more complex nitrogen-bearing molecules. Nitrogen heterorcycles have never been found before on the Martian surface or confirmed in Martian meteorites.

Curiosity also found benzothiophene, a carbon- and sulfur-bearing molecule that’s been found in many meteorites. Such molecules might have seeded prebiotic chemistry across the early solar system.

Curiosity project scientist Ashwin Vasavada at NASA’s Jet Propulsion Laboratory in Southern California said:

This is Curiosity and our team at their best. It took dozens of scientists and engineers to locate this site, drill the sample, and make these discoveries with our awesome robot. This collection of organic molecules once again increases the prospect that Mars offered a home for life in the ancient past.

Wet chemistry reveals organic molecules

One of the ways Curiosity detects organic molecules is with wet chemistry. The minicab inside the rover, called Sample Analysis at Mars (SAM), can drop samples of powdered rock into small cups containing solvent. The chemical reactions that take place can break apart larger molecules. These molecules can be difficult to detect otherwise. There are several cups. Two of them contain the solvent tetramethylammonium hydroxide (TMAH). Those two cups are reserved for the “highest-value” samples. And Mary Anning 3 was the first sample tested in one of those cups.

As a comparison, the research team also tested the wet chemistry technique back on Earth. They used a piece of the famous Murchison meteorite, which is over 4 billion years old. The results were interesting, indeed. Murchison contains organic molecules, just like the Mary Anning 3 samples. When the scientists exposed the meteorite sample to the TMAH solvent, the larger molecules broke down into smaller ones. These included some of the organics found in Mary Anning 3, including benzothiophene.

This similar breakdown of organics shows that the organic molecules in Mary Anning 3 could indeed have resulted from the breakdown of more complex organic molecules.

Largest organic molecules on Mars

The new findings by Curiosity also complement the announcement last year of the largest organic molecules ever found on Mars. Curiosity made that discovery as well.

But determining that for sure (or not) will likely require the samples the rover took to be brought back to Earth for closer study.

Those molecules included the long-chain hydrocarbons decane, undecane and dodecane. Scientists think they are the remains of fatty acids. And they are the most complex organics yet found on Mars. Plus, last February, NASA scientists said that these organics are hard to explain without biology:

As the non-biological sources they considered could not fully explain the abundance of organic compounds, it is therefore reasonable to hypothesize that living things could have formed them.

Leopard spots and poppy seeds

The findings also come after the Perseverance rover, in Jezero Crater, found intriguing leopard spots and poppy seeds in rocks. First announced in 2024, the chemical signatures of the markings suggest they might be traces of ancient microbial life.

Bottom line: NASA’s Curiosity rover has identified the most diverse collection of organic molecules on Mars ever found. They include some organics never seen before.

Source: Diverse organic molecules on Mars revealed by the first SAM TMAH experiment

Via NASA

Read more: NASA says organics on Mars are hard to explain without life

Read more: Surprisingly big organic molecules on Mars: A hint of life?

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Comet R3 PanSTARRS to pass closest to Earth tomorrow

Comet C/2025 R3 (PanSTARRS) passed closest to the sun on April 19, 2026. It will pass closest to Earth on April 26. The comet will get as close as 45.5 million miles (73.2 million km) from Earth. That’s slightly closer than half the Earth-sun distance. But when Comet PanSTARRS passes closest to Earth, it will be in the sun’s direction as seen from Earth. So we won’t see it in our sky. But, as you can see from the image above, our sun-watching spacecraft caught its passage!

By the time the comet is far enough from the sun in the Northern Hemisphere to spot, it’ll likely be quite dim again. But astrophotographers can give it a try. And observers in the Southern Hemisphere will have a chance in late April to try to spot Comet PanSTARRS low on the western horizon just after sunset. Keep track of the comet’s brightness here.

Images of the comet from our community

EarthSky friend John Ashley shared his video of Comet R3 PanSTARRS rising before the sun in Arizona on April 12, 2026. John wrote: “Comet PanSTARRS rises beyond the Smithsonian’s Whipple Observatory. The comet is barely visible to the eye but an easy target with binoculars. And it’s getting brighter each morning.” Thank you, John!

More comet pics

Did you catch a pic of the comet? Submit it to us!

Bottom line: Comet R3 PanSTARRS is closest to Earth on April 26. Check out this cool image from a sun-watching spacecraft! And enjoy these fantastic community photos.

Read more: The best comets of 2026: Here’s what to watch for

Read more: Binoculars for stargazing: Our top 6 tips here

The post See great pics of Comet R3 PanSTARRS from our community first appeared on EarthSky.

• Ultra-faint dwarf galaxies – tiny satellites of the Milky Way – act as cosmic fossils. They preserve clues about radiation and star formation in the early universe.
• New high-resolution simulations show these faint galaxies are extremely sensitive to early-universe conditions. Those conditions determined whether small dark matter halos formed stars or stayed dark.
• Future observations from the Vera C. Rubin Observatory could use these galaxies to reconstruct the universe’s earliest climate.

The Royal Astronomical Society published this original story on April 24, 2026. Edits by EarthSky.

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Milky Way’s ‘ultra-faint dwarf galaxies:’ our littlest galaxy cousins

Ultra-faint dwarf galaxies – tiny satellite galaxies orbiting the Milky Way – have long been seen as cosmic fossils.

Now, a new study published April 24, 2026, in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society uses an unprecedented set of simulations to show just how powerfully these faint systems can reflect the conditions of the early universe. And it tells us why some galaxies grew and others did not.

These little galaxies could also reveal what the universe’s earliest “climate” was like. For example, it could show the level of radiation and how this impacted whether and where stars formed.

Astronomers often describe dwarf galaxies as small cousins of the Milky Way. They form in small dark matter halos predicted by the standard model of cosmology. The faintest examples of such systems are extreme in both size and fragility. And they lie on the boundary of our knowledge about galaxy formation and dark matter.

Simulating tiny galaxies

Associate professor Azadeh Fattahi, of the Oskar Klein Centre (OKC) in Stockholm, led the new study with the LYRA collaboration and in collaboration with Durham University and the University of Hawaii. Fattahi said:

In this work we presented a brand-new suite of cosmological simulations focused on the faintest galaxies in the universe, with an unprecedented resolution. These are by far the largest sample of such galaxies ever simulated at these resolutions. The smallest galaxies are called ultra-faint dwarf galaxies, which are a million times less massive than the Milky Way or even smaller. Due to their small size these galaxies have proven very difficult to model and simulate.

This new simulation suite represents a major step forward, enabling a systematic view of how these galaxies form and evolve.

A down-to-earth analogy

Shaun Brown led the study while working at OKC and Durham University. Brown said:

A useful analogy is to plants and crops and how they grow is sensitive to the weather conditions. In the same way that the yield of a crop in summer can indirectly tell you a lot about what the weather in spring must have been like, the properties of faint dwarf galaxies today can tell us a lot about the conditions, or weather, of the universe at a much earlier time.

What makes the results especially timely is that the simulations do more than reproduce faint dwarf galaxies. They suggest that these local objects can act as a probe of the universe’s earliest “climate.” The team explored how different assumptions about the early radiation environment influence which small dark matter haloes manage to form stars at all. Brown explained:

In the paper we studied two different assumptions about the properties of the early universe when it was less than 500 million years old, to understand the effect on the properties of these small galaxies today when the universe is 13 billion years old. We found that these small ultra-faint galaxies are very sensitive to these changes, while more massive galaxies, like our Milky Way, don’t really care.

For the smallest galaxies, early conditions can decide whether they become visible galaxies or remain starless dark matter halos.

Future research

That sensitivity opens a clear path to testing early-universe physics with upcoming observations. Fattahi said:

Excitingly, in the near future we will have data from the Vera C. Rubin Observatory which will be able to find many more of these ultra faint dwarfs around the Milky Way.

Many astronomers hope Rubin can deliver a near-complete census of Milky Way satellite galaxies. And these simulations hint that this census may carry information far beyond our local neighborhood. Fattahi added:

Our work suggests that these upcoming observations of the very local universe will be able to constrain what the universe at its infancy looked like, something we currently cannot directly access with other observations.

The result is particularly relevant in the light of recent discoveries, by the James Webb Space Telescope, of galaxies in the early universe. Some of those galaxies are unexpectedly massive and bright.

If the early universe is producing surprises at large distances, then local relics from the same epoch – ultra-faint dwarfs – may provide an additional route to understanding what happened, according to Fattahi.

Looking ahead, Fattahi’s team plans to tackle questions that are still open in modern galaxy and structure formation. For example, where did the very first generation of stars form in the universe? Or what do the properties of ultra-faint dwarf galaxies tell us about the nature of dark matter?

Bottom line: Ultra-faint dwarf galaxies preserve clues to early-universe conditions, acting as cosmic fossils. Simulations show early radiation shaped whether these tiny galaxies formed stars or stayed dark.

Source: LYRA ultra-faints: The emergence of faint dwarf galaxies in the presence of an early Lyman-Werner background

Via Royal Astronomical Society

The post Milky Way’s ‘ultra-faint dwarf galaxies’ help probe early universe first appeared on EarthSky.

• We’ve all seen waves on lakes or oceans. How would wave action be different on other planets, or moons, outside our solar system?
• Waves would vary greatly on other worlds, researchers from MIT say in a new study called PlanetWaves.
• These waves could be in water like on Earth, or other more exotic liquids, like the methane/ethane lakes and seas on Saturn’s moon Titan.

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Waves on other planets

We’re all familiar with waves on Earth, which vary from gentle ripples on a summer day to giant tidal waves. But what would waves be like on other planets? In our solar system, we can look for clues on Saturn’s large moon Titan, which has lakes and seas of methane/ethane. And also what might waves have looked like on ancient Mars, with its long-gone water lakes and probable ocean? On April 16, 2026, researchers at the Massachusetts Institute of Technology (MIT) said in a new study that waves would likely vary greatly from planet to planet, or moon to moon.

The study looked at Titan, ancient Mars and three different exoplanets that might have surface liquids, ranging from water to lava.

The new peer-reviewed paper was published in JGR Planets on April 3, 2026.

The PlanetWaves model

For the new study, the researchers developed a new scientific model called the PlanetWaves model. The model can predict how waves might behave in oceans or lakes on other rocky planets or moons. The study included Saturn’s moon Titan, ancient Mars and three exoplanets. It can also take into account different kinds of liquids. For example, Titan’s oceans and lakes are composed of liquid hydrocarbons – methane and ethane – instead of water.

According to the model, a gentle wind would be sufficient to create large waves on Titan. But on the exoplanet 55-Cancri e, hurricane-force winds would barely make a ripple. Scientists think that 55-Cancri e is likely covered in an ocean or lakes of lava. Study author Andrew Ashton, an associate scientist at the Woods Hole Oceanographic Institution (WHOI), said:

On Earth, we get accustomed to certain wave dynamics. But with this model, we can see how waves behave on planets with different liquids, atmospheres and gravity, which can kind of challenge our intuition.

Titan, land of lakes

Titan is of particular interest to the scientists. It’s a moon, but it’s also the only other body in our solar system, our local neighborhood of space, known to have lakes and seas on its surface. And it’s a lot closer to us than exoplanets orbiting distant suns. As co-author Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric and Planetary Sciences at MIT, noted:

Anywhere there’s a liquid surface with wind moving over it, there’s potential to make waves. For Titan, the tantalizing thing is that we don’t have any direct observation of what these lakes look like. So we don’t know for sure what kind of waves might exist there. Now this model gives us an idea.

It should be noted that we do have visual observations of the lakes, but only from radar on the former Cassini spacecraft. The global orangish haze or “smog” that surrounds Titan completely obscures the view from us in regular light.

In the future, NASA might send a probe directly to one of the lakes on Titan. But it would need to withstand any waves that might occur. Una Gaylin Schneck, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), is the lead author. She said:

You would want to build something that can withstand the energy of the waves. So it’s important to know what kind of waves these instruments would be up against.

Modeling Wind-Driven Waves on Other Planets – Applications to Mars, Titan, and Exoplanets: agupubs.onlinelibrary.wiley.com/doi/full/10…. -> Waves hit different on other planets: news.mit.edu/2026/waves-h… – waves should vary widely from one planet to another, according to a new model.

— (@cosmos4u.bsky.social) 2026-04-16T21:24:02.235Z

Various factors involved

What kinds of waves a planet or moon has will depend on various conditions. This can include the strength of the world’s gravity, the density and composition of its atmosphere and the composition of its surface liquids. Schneck said:

There have been attempts in the past to predict how gravity will affect waves on other planets. But they don’t quantify other factors such as the composition of the liquid that is making waves. That was the big leap with this project.

As for the liquids involved, there are factors such as density, viscosity and surface tension. Atmospheric pressure will also help determine what kinds of waves form. Ashton said:

Imagine a completely still lake. We’re trying to figure out the first puff that will make those first little tiny ripples, on up to a full ocean wave.

Testing how to make waves on Titan

Using the PlanetWaves model, the researchers tested wave-making processes. The first tests used data from buoys on Lake Superior. The model successfully predicted the wind speeds needed to create waves and how big the waves would be.

The researchers then used that data to look at the lakes and seas of Titan. Even though the liquids are methane and ethane, not water, the model showed that waves should easily form on Titan. This is largely due to Titan’s weaker gravity and lower atmospheric pressure. Schneck explained:

It kind of looks like tall waves moving in slow motion. If you were standing on the shore of this lake, you might feel only a soft breeze but you would see these enormous waves flowing toward you, which is not what we would expect on Earth.

Models like PlanetWaves might also help solve other related mysteries on Titan, such as why deltas seem to be mostly absent where the rivers meet the lakes and seas. Perron said:

Unlike on Earth, where there is often a delta where a river meets the coast, on Titan there are very few things that look like deltas, even though there are plenty of rivers and coasts. Could waves be responsible for this? These are the kinds of mysteries that this model will help us solve.

Waves on Mars’ ancient ocean?

Next, the researchers applied the data to ancient Mars. We know there were once many lakes on its surface. And there is growing evidence for an ancient ocean. Winds in the previously thicker atmosphere could have easily produced waves. But the model showed that as the atmosphere gradually thinned and was mostly lost to space, waves would have required stronger winds to form.

Waves on 3 exoplanets

Lastly, the research team looked at three different exoplanets.

LHS 1140 b is a “cool super-Earth,” meaning that it is colder and larger than Earth. Scientists think the planet might host liquid water, with an eyeball ocean. But due to its size, it has stronger gravity. The model showed that the same wind on Earth would generate much smaller waves of water on this planet, due to the difference in gravity. This planet is also one of 45 best planets to search for alien life for the new ‘Project Hail Mary’ study.

Next, Kepler 1649 b is a Venus-like planet, which has a gravity similar to Earth’s. It’s thought to have lakes of sulfuric acid, which is about twice as dense as water. The model suggested that it would take strong winds to make even a ripple on those lakes.

Finally, 55-Cancri e. It’s a hot lava world with both higher gravity than Earth and a much denser, more viscous surface liquid. Scientists suspect that the planet hosts oceans of liquefied rock. The researchers found that hurricane-force winds, about 80 miles per hour (129 km per hour), would generate only small waves of a few centimeters in height. The denser liquid makes it harder for waves to form.

Bottom line: A new study from MIT suggests that waves on other worlds should vary greatly. Scientists are looking at the lakes and seas of Saturn’s moon Titan for clues.

Source: Modeling Wind-Driven Waves on Other Planets: Applications to Mars, Titan, and Exoplanets

Via MIT

Read more: Shorelines of Titan’s seas likely shaped by waves

Read more: What causes ocean waves?

The post Waves on other planets vary widely, new MIT study suggests first appeared on EarthSky.

• Life as we know it needs water to exist. But how much water does an exoplanet need to be habitable in the long term?
• More water than previously thought is the answer suggested by a new study.
• At least 20 to 50% of the water on Earth would be required. Otherwise, the planet might start losing water on its surface and become arid.

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How much water does an exoplanet need to stay habitable?

Astronomers consider water to be essential for life as we know it to form on a given planet. But, unfortunately, not all watery worlds stay watery. Venus, according to some studies, once had as much water as Earth does … but is now scorching hot, arid, and lifeless.

A new study from researchers at the University of Washington in Seattle suggests that Venus starting out with slightly less water than Earth could have made all the difference. The researchers said on April 15, 2026, that this lack of water could have destabilized the cycle of carbon between the planet’s atmosphere and interior. This would have caused carbon dioxide to build up in the air, raising temperatures and causing more water to evaporate.

So how much water does a world need to stay habitable? The study suggests that a rocky Earth-sized planet would need at least 20 to 50% of the water in Earth’s oceans to avoid this fate. That should be enough to maintain the crucial carbon cycle, keeping water on the surface long enough to potentially give water-based life time to develop.

This applies to planets in the habitable zone of their stars in particular. That’s the region where temperatures could allow liquid water to exist to begin with.

The researchers – lead author Haskelle Trigue White-Gianella and co-author Joshua Krissansen-Totton – published their new peer-reviewed results in The Planetary Science Journal on April 15, 2026.

The habitable zone

Scientists have long focused on the habitable zone around stars in the search for life. That’s because this is where liquid water could exist on rocky planets. But that depends on other factors, too, such as the composition of the atmosphere (if there is one) and the planet itself. White-Gianella said:

When you are searching for life in the broad landscape of the universe with limited resources, you have to filter out some planets.

Carbon Cycle Imbalances on Arid Terrestrial Planets with Implications for Venus: iopscience.iop.org/article/10.3… -> Planets need more water to support life than scientists previously thought: www.washington.edu/news/2026/04…

— (@cosmos4u.bsky.social) 2026-04-15T22:26:18.349Z

Arid planets with little water

To try to determine how much water a planet needs to be habitable, the study focused on arid planets that likely only have a little water. White-Gianella explained:

We were interested in arid planets with very limited surface water inventory, far less than one Earth ocean. Many of these planets are in the habitable zone of their star, but we weren’t sure if they could actually be habitable.

The carbon cycle

Since some of those planets are in the habitable zone, could they be habitable even with less water?

The researchers found that it depends on something called the carbon cycle. This cycle, driven by water, exchanges carbon between the atmosphere and interior of the planet, over millions of years. This process helps stabilize temperatures on the surface of the planet.

How does it work? Volcanoes emit carbon dioxide. The carbon dioxide accumulates in the atmosphere. Eventually it falls back to Earth in rain. Subsequently, the rain erodes and chemically reacts with rocks. The runoff in rivers brings the carbon back to the ocean, where it sinks down to the seafloor. Carbon-rich oceanic plates then move below the continental plates. Finally, millions of years later, the carbon comes back up to the surface in the form of mountains.

Low water levels

But there’s a catch. What if water levels drop too low for rainfall to occur? The carbon removal segment of the cycle – erosion by rain – can no longer keep up with carbon emissions from volcanoes. As a result, carbon dioxide builds up in the atmosphere. And this could create a runaway greenhouse effect, with temperatures becoming too hot to sustain life. This is what scientists say happened with Venus. As White-Gianella noted:

So that, unfortunately, makes these arid planets within habitable zones unlikely to be good candidates for life.

Krissanen-Totton said:

This has implications for a lot of the potentially habitable real estate out there.

Updating previous carbon models

The new carbon model of the study, focusing on arid planets, is an update to previous models. Those models focused more on water and cooler planets. They included factors such as evaporation from sunlight. But they neglected other factors, such as wind. Krissanen-Totton explained:

These sophisticated, mechanistic models of the carbon cycle have emerged from people trying to understand how Earth’s thermostat has worked – or hasn’t – to regulate temperature through time.

The new results show that even if a planet starts out with lots of surface water, it can lose it later on if the carbon cycle is interrupted.

Venus as an exoplanet analog

We already know of one such planet, and it’s in our own solar system: Venus. Scientists think Venus once had much more water, maybe even oceans. But Venus has since lost that water. Why?

Today, Venus is scorching hot on its surface, too hot for life. The dense carbon dioxide atmosphere traps heat so it can’t escape.

The researchers in the new study suggest that Venus might have had slightly less water than Earth early on. This caused an imbalance in the carbon cycle. And as the carbon dioxide accumulated in the atmosphere, the temperature kept rising.

Venus is a good analog for the kinds of exoplanets the researchers studied. As White-Gianella noted:

It’s very unlikely that we will land something on the surface of an exoplanet in our lifetime, but Venus – our next-door neighbor – is arguably the best exoplanet analog.

Speaking of Venus, another study, from 2025, suggests that Venus actually has more water in its atmosphere than previously thought. It’s still fire and brimstone on the surface, but perhaps this water could help sustain microbes that scientists have postulated could survive higher up in the atmosphere.

Bottom line: How much water on exoplanets does life need? A new study suggests at least 20 to 50% of the water on Earth.

Source: Carbon Cycle Imbalances on Arid Terrestrial Planets with Implications for Venus

Via University of Washington

Read more: Water on exoplanets is mostly hidden deep inside

Read more: New study says water in Venus’ clouds surprisingly abundant

The post How much water on exoplanets does life need? first appeared on EarthSky.