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• ESO’s Very Large Telescope has captured an image of the recently discovered companion to the famous red supergiant Betelgeuse at its expected location.
• To confirm the object is Betelgeuse B astronomers will need to observe it in one year on the other side of the star.
• The likely companion star is around 2 to 3 times the mass of our sun.

The European Southern Observatory shared this press release on July 28, 2026. Edits by EarthSky.

Image shows evidence of Betelgeuse companion star

A year ago, U.S. astronomers announced a companion for the red supergiant star Betelgeuse. This star is famous for being nearby and poised to explode. And now European astronomers have confirmed that important discovery. Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), a team led by French researcher Miguel Montargès obtained the clearest image ever of what is likely Betelgeuse B, the star orbiting Betelgeuse. He’s an astronomer at the Observatoire de Paris – PSL, France, and lead author of the study published today in Astronomy & Astrophysics. Montargès recalls:

I jumped from my chair when I saw the processed images.

Betelgeuse, in the constellation Orion the Hunter, is easily visible with the unaided eye. Want to see it? Read this article about the return of Orion before dawn at this time of year. Excitingly, the star is known to change in brightness. It has been observed for millennia. However, it still surprises astronomers.

The brightness of Betelgeuse varies

For a long time, astronomers have looked for the potential companion to Betelgeuse. It was originally proposed to explain Betelgeuse’s brightness changes. Then two studies published in 2024 predicted that in December that year, the companion would be furthest from Betelgeuse and hence easier to spot. Montargès and his team got to work, observing the star with ESO’s VLT in December 2024 and spending several months processing the data.

Originally the companion star was thought to be about as massive as the sun. However, the new observations reveal that Betelgeuse B has around two to three times the mass of the sun. Montargès explained:

Honestly, I thought we did not have the sensitivity to detect Betelgeuse B as it was predicted. Because it is more massive than predicted, we see it! The fact that we can still discover a nearby companion, more massive and brighter than the sun, around such a well-studied star is remarkable. These are among the best moments in science: seeing something new, unexpected.

The Betelgeuse companion imaged

Betelgeuse B was directly imaged, meaning the light from the star itself was detected, using the SPHERE instrument on ESO’s VLT. While there was evidence for the existence of this companion star, including a possible direct detection with the Gemini North Telescope in Hawaii, this is the strongest evidence for, and clearest image yet of, Betelgeuse B. Co-author Anthony Boccaletti, also an astronomer at the Observatoire de Paris said:

It is remarkable to see how SPHERE and advanced post-processing techniques, originally developed to find exoplanets, also excel at detecting a companion around a massive, evolved star like Betelgeuse.

Montargès added:

To be certain that the companion is really there, we still need to observe it in one year on the other side of the star. But there is very little space left for doubt.

Betelgeuse’s great dimming caught attention

A few years back, Betelgeuse was the subject of attention from astronomers and non-astronomers alike when it visibly started dimming. As an evolved supergiant star, Betelgeuse is expected to die in a supernova explosion. So the dramatic dimming of Betelgeuse led some to speculate it could be about to explode. A group of astronomers led by Montargès studied the star with ESO’s VLT, finding it was instead obscured by a cloud of dust.

The potential detection of Betelgeuse B will prompt astronomers to investigate how the companion could affect Betelgeuse’s anticipated supernova explosion. Montargès concluded:

The question is truly opened whether this companion is going to have an impact on the evolution of the red supergiant.

Bottom line: A recent image appears to show the companion star of Betelgeuse, know as Betelgeuse B. It’s the strongest evidence yet that the beloved red supergiant star has a companion star.

Via ESO

Read more: Betelgeuse’s companion star leaves detectable wake

Read more: New details about Betelbuddy, Betelgeuse’s companion star

The post Companion for Betelgeuse update! A new image first appeared on EarthSky.

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Falcon rocket will hit the moon on August 5

On July 27, 2026, another paper came out on arXiv with predictions of what might happen when a rocket hits the moon in a few days. Read on for more!

In January 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.

Current estimates are that the upper stage will hit the moon at 1:35 a.m. CDT (6:35 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.

New research on the rocket impact

On July 27, 2026, a new paper came out on arXiv from researchers at University of Texas-Austin. Lead author William Jo contacted me to explain what the new paper details:

My group at UT Austin submitted a paper to Geophysical Research Letters this past Friday modeling [the physical processes]. … We predict the debris plume from the August 5 impact (06:34 UTC) will have the central ejecta spike reaching ~75 to 100 km altitude, the curtain ~15 to 20 km, and spread 183 km laterally near the sunlit limb. … Our calculations suggest the plume should be several orders of magnitude brighter than the dark-sky background for the first few minutes after impact.

So the plume should be visible. …

A spent rocket stage is a hollow, human-made body, and there are very few impact models for objects like it. They seem to produce very different plumes than natural impactors (like asteroids or comets) do. Watching this one gives us a rare chance to open up ejecta-plume science and calibrate those models against a real event, which matters for every future thing we deliver to the Moon. My concern is that most observers will stop at the sub-second flash and never track down the ejecta, which is the part that should actually be visible, and where the science is. Our work shows that this impact may be worth a look.

Read on for more about where and when to look!

Will we be able to see the impact?

The moon will be close to last quarter phase on August 5, 2026. By 1:35 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? It appears the impact will occur near the edge, or limb, of the moon, close to the Einstein crater.

On July 17, 2026, a another paper came out with details on planning observations for the upcoming collision. This event provides scientists and nonscientists alike a perfect opportunity to record a lunar impact in real time. The data collected can help scientists better understand dust dynamics from impacts, the hazards of the resulting debris and more.

In the July 17 paper, scientists used Bill Gray’s tracking data to show that the rocket body (39 feet or 12 meters long and 13 feet or 4 meters wide at a weight of around 8,800 pounds or 4,000 kilograms) will gouge a new crater into the surface. The crater won’t be as large as one created by a solid object such as an asteroid, because the rocket body is largely hollow. But still, the new crater should be around 66–98 feet or 20–30 meters wide. It said that we can also expect a huge cloud of dusty lunar soil to launch a few miles into space above the impact site.

Will telescopes in space and from observers in the Americas be able to see all this? It’s possible. The paper said:

Potential observables from this event include the flash at the time of impact (likely lasting less than a second) and the ejecta plume (lasting minutes to tens of minutes). … This event is an ideal opportunity to calibrate measurements of flash brightness and plume dynamics against a known event, should either be detected.

Previous lunar impact

After the impact, NASA’s Lunar Reconnaissance Orbiter might be able to get an image of the resulting crater. It’s happened before.

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 1.51 miles (2.43 kilometers) 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. Who can see it? And what might you see? Answers here.

Source: Observational planning for the 2026 August 5 Falcon 9 Upper Stage lunar impact

Source: Predicted Ejecta Dynamics and Observability of the 2026 Falcon 9 Upper Stage Lunar Impact
Read more: Satellites swarm the night sky in this new video

Read more: Starlink satellite breaks up, scatters debris

The post A rocket will hit the moon on August 5: Here’s the latest first appeared on EarthSky.

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Alien intelligence: Have we been searching wrong?

In the movie Contact, Jodie Foster’s character – the astronomer Ellie Arroway – sits by a row of radio telescopes, listening through headphones for signals from alien intelligence. This scene has become symbolic of SETI (the Search for Extraterrestrial Intelligence). But now it turns out Ellie’s character, and SETI astronomers generally, might have been listening to the wrong radio channels.

SETI astronomers search for radio signals, mostly from a specific band of the radio spectrum: the frequencies between 1.42 and 1.66 GHz. And, on July 24, 2026, Louisa Mason of the University of Manchester in the U.K. said we might be searching in the wrong way. She told astronomers attending the National Astronomy Meeting in Birmingham in the U.K. that different radio frequencies might yield a result.

Astronomers originally chose the frequencies between 1.42 and 1.66 GHz, which they call the water hole, because of its location between hydrogen (H) and hydroxyl (OH). These elements combine to form water. And astronomers think water is likely essential to life. Besides the relation to water, this frequency is exceptionally quiet and free of background noise. So it would be a good frequency for aliens to communicate across vast distances, like a cosmic watering hole.

But Mason suggests we should be looking at higher radio frequencies. And she’s already gotten started. Mason and her colleagues looked at data from past observations with the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile.

It was the first-ever search for extraterrestrial intelligence using the powerful ALMA telescope.

The search for aliens using ALMA

Mason said:

For decades, SETI searches have concentrated on a relatively small part of the radio spectrum. We wanted to ask what might happen if we looked somewhere very different. The millimeter and submillimeter radio bands remain almost completely unexplored for SETI, so this is really about opening up a new area of parameter space to search.

To start, the team looked at four archived ALMA observations. They were looking for narrowband radio signals that did not look natural. Astronomers call these technosignatures.

So far, they haven’t found any technosignatures. But their first attempt did reveal a hidden opportunity within every radio observation. Every time a radio telescope points at its target, it captures a myriad of other stars in its field of view.

Stars beyond the main target

Every time a radio telescope points at its target, it’s capturing data from its goal plus a slew of stars in the same field of view. Astronomers call this the stellar bycatch. Astronomers use data from ESA’s Gaia mission to get an idea of what population is within this stellar bycatch.

But Mason and team used the Besançon Galactic Model to get a better estimate of the full stellar population in each observation. Gaia has restrictions in magnitude (the brightness of stars) and distance, among other issues. So the Besançon Galactic Model allowed the team to get a fuller look at what might be in their data.

For example, the Besançon Galactic Model revealed that a previous SETI survey of 1,327 telescope pointings really included more than 6.1 million stars in total. The Gaia estimate had identified only 288,000 stars. Mason said:

One of the most exciting things about this work is realizing that we’ve surveyed many more stars than initially thought. Even a very small observation can contain a huge number and diversity of stars that we might never have intended to study. By combining high-frequency observations with galactic simulations, we can better understand exactly what we’ve searched and where we should look next.

Bottom line: Some astronomers believe we should search for alien signals at higher radio frequencies than those traditionally used in SETI. They’ve already begun doing just that.

Via Royal Astronomical Society

The post Are we listening for alien intelligence the wrong way? first appeared on EarthSky.

U.K. astronomer Guy Ottewell published Juno in Aquarius on his website on July 24, 2026. Edits by EarthSky. Reprinted here with permission. Thank you, Guy!

Asteroid Juno reaches opposition July 26

The large asteroid 3 Juno will be at opposition – when it’ll lie opposite the sun as viewed from Earth – on July 26, 2026. All asteroids and planets are brightest around the time of their oppositions, when they lie opposite the sun in our sky. That’s when they are closest to us in their orbits. They also rise around sunset and set around sunrise, so they are visible all night.

At opposition in 2026, Juno will shine at 9th magnitude. That means it is too dim for the unaided eye to see. But a telescope will reveal this little world, moving among the stars of the constellation Aquila the Eagle.

And it is theoretically within the reach of powerful binoculars. You’d have to look for Juno on more than one night and note a star that moved.

Juno and the other early asteroids were discovered in that way.

Juno’s discovery

Juno’s official name is 3 Juno, because it was the 3rd asteroid ever to be found. The German astronomer Karl Ludwig Harding spied it in the early 1800s, amidst a rush of asteroid discoveries. 1 Ceres was discovered in 1801, 2 Pallas in 1802, 3 Juno in 1804 and 4 Vesta in 1807.

Of these 1st four, Vesta is brightest. At Vesta’s opposition, it can reach as bright as magnitude 5.1, making it visible to observers with the unaided eye.

Now astronomers have tracked and documented over 1.5 million individual asteroids. And thousands of asteroids are still discovered each year. Most circulate in the asteroid belt located between Mars and Jupiter. But some asteroids orbit nearer in, and some even cross Earth’s orbit. All are below unaided-eye brightness … except sometimes 4 Vesta.

The 1st four asteroids are observable with telescopes or steadily held binoculars each year. And 3 Juno is usually the dimmest of the 1st four.

Main belt asteroids typically have orbital periods between 3 and 5 years.

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Juno orbits near the celestial equator

Juno’s oppositions – unlike that of other asteroids – always occur near the celestial equator, the imaginary line around our sky directly above Earth’s equator. The chart below explains more about this phenomenon.

Bottom line: The asteroid Juno – officially known as 3 Juno – will be at its brightest around its opposition on July 26, 2026. It’ll be located among the stars of the constellation Aquila the Eagle.

Via Universal Workshop

Source: Guy Ottewell’s 2026 Astronomical Calendar

Read more: Guy Ottewell honored with an asteroid in his name

The post Asteroid Juno at its best now, around opposition first appeared on EarthSky.

• Teghaza 001 is a meteorite that came from Mars. Prospectors found it in the Sahara Desert in 2022.
• Analysis of this rock suggests Mars began to lose its water very early in its history.
• Plus, it reveals Mars had a crust similar to granite, which is surprising given the planet lacks plate tectonics.

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Teghaza 001, the oldest known Mars meteorite

Many pieces of Martian material have been ejected from the red planet and reached Earth as meteorites. And one of the more recently discovered Martian meteorites might be the oldest yet.

That’s what a team of scientists, led by the California Institute of Technology (Caltech), said on July 16, 2026. Prospectors found the meteorite – named Teghaza 001 – in the Sahara Desert in September 2022. And researchers have identified the piece of Mars’ crust as being over 4.1 billion years old.

The meteorite hints that the planet was already losing its water at that early stage in its life. Plus, it points to a granite-like crust on ancient Mars. That’s surprising, as the formation of granite on Earth is associated with tectonic activity … and Mars lacks plate tectonics.

The not-yet peer-reviewed paper is available as a preprint on the ESS Open Archive (April 14, 2026). Additional papers are also expected.

This meteorite, called Teghaza 001, “will revolutionize the way that we think about early Mars.”Learn more: https://scim.ag/4yDBSYK

— Science Magazine (@science.org) 2026-07-21T22:40:01.528162083Z

A view into Mars’ past

Paper co-author Lee Saper is a geochemist at NASA’s Jet Propulsion Laboratory (JPL). He gave a talk at the Goldschmidt geochemistry conference in Montreal, Canada, on July 14. He said that the meteorite:

… will revolutionize the way that we think about early Mars.

And he’s likely right.

Teghaza 001 is only the second known Martian meteorite from the Martian crust in the earliest period of the planet’s history. The other one is Allan Hills 84001. So now, scientists have two meteorites to work with instead of just one. Lydia Hallis, a planetary scientist at the University of Glasgow, said:

We’ve doubled our old meteorites. There will be a lot of people, including me, who want to get a piece of this.

So what does the meteorite show?

Tegzaza is rich in both zircons and silicon. Zircon minerals contain tiny amounts of uranium. The uranium decays into lead over time. Since it decays at a known rate, scientists can use it to determine the age of the meteorite.

If the zircon minerals melt or are exposed to fluids, though, then their “clocks” are reset to zero. This means that the meteorite might be even older than 4.1 billion years. Christopher Herd, a geologist at the University of Alberta, said:

There’s more of a story to this rock than most other Martian meteorites.

Mars meteorite hints at granite-like crust on ancient Mars

But there was another surprise in the meteorite: it contained a lot of silicon. This hinted at granite-like rocks on ancient Mars. As Eva Scheller, a planetary scientist at Stanford University, noted:

It’s very strange; we don’t expect that.

Scientists never expected Mars to have much granite since it lacks plate tectonics (the division of a planet’s upper crust into multiple different pieces, or plates). On Earth, granite forms from cooling magma. And most of that magma is generated by the movement of tectonic plates. Meanwhile, most of Mars’ crust is composed of solid basalt.

But it’s starting to look like Mars did once have at least some granite, or granite-like rock. Impacts from meteorites have exposed some deposits. And last year, the Perseverance rover discovered a rock outcrop, called Plankeholmane, that looks a lot like granite on Earth. It contained quartz, a key component of granite.

And last year, the rover found an odd speckled white rock called Atoko Point that also appeared quite granite-like. It contained pyroxene and feldspar. Feldspar is also a component of granite on Earth.

How was Mars able to produce such deposits without plate tectonics? Scientists don’t know yet. This evidence also points to complex magma systems on early Mars, as does this other recent study.

When Mars dried up

The meteorite also provides valuable clues about past water on Mars. Both it and the Allan Hills meteorite show that Mars had more water early in its history. But they also indicate that Mars began to lose its water early on, as the planet’s magnetic field disappeared and the atmosphere thinned and became much colder. Considering that these meteorites are at least 4.1 billion years old, and Mars – like Earth – formed some 4.5 billion years ago, this loss of water seems to have come in the planet’s infancy.

The clues come from the ratios of hydrogen in the meteorites. When Mars began to lose its water, the higher ratio of hydrogen – the primary component of water – to deuterium dropped. Super said:

This is the product of rapid hydrogen loss from the juvenile Martian atmosphere.

The new analysis of Teghaza 001 has provided new clues about Mars’ ancient past. And it also raises new questions. It will be interesting to see what else it and similar Mars meteorites reveal!

Bottom line: A new analysis of the the oldest known Mars meteorite, Teghaza 001, reveals evidence for a granite-like crust and the start of the loss of water on early Mars.

Source: Teghaza 001: An ancient Martian gabbroic diorite derived from previously unsampled Martian crust and mantle

Via Science

Read more: A famous Mars meteorite, now with nitrogen

Read more: Methane in Mars meteorites = life?

The post Oldest Mars meteorite reveals Mars lost its water early first appeared on EarthSky.

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Did we find an exomoon around a brown dwarf?

Exomoons are moons that exist outside our own solar system. We’ve yet to definitively find a single one! That’s because they are small and dim, circling exoplanets that are also small and dim, hidden in the glare of the stars they orbit. But on July 22, 2026, the European Southern Observatory said astronomers using the Very Large Telescope in Chile believe they have detected an exomoon.

Only, there’s one problem: it doesn’t orbit a planet. Instead, it orbits a brown dwarf. A brown dwarf is an object that’s too massive to be considered a planet, but not massive enough to ignite and shine like a star. And this particular brown dwarf orbits a star, named CD-35 2722. So astronomers are debating what to call the newly discovered object. Is it the first discovered exomoon, or something else?

The researchers published their peer-reviewed paper on July 22, 2026, in the journal Nature.

A ‘super weird’ system

Not all brown dwarfs orbit stars, but this one does. The star in this system is named CD-35 2722, and it’s about half the mass of our sun. But even though the brown dwarf orbits this star, it’s not a planet, because it’s too massive. Brown dwarfs are so massive compared to planets that they’re sometimes called “failed stars.” Though far heavier than the objects we call planets, they aren’t quite massive enough to begin nuclear fusion and shine like a star does.

And then we have the newly discovered object, which orbits the brown dwarf. Normally we think of a moon as something that orbits a planet, which orbits a star. So what orbits a brown dwarf? Is it an exomoon? That’s what astronomers are having to decide: the semantics of the system. In any case, the lead author of the new study, Kevin Hoy, an ESO student in Chile, calls it:

super weird.

An exosatellite?

Right now, the team is calling the object an exosatellite. The object is at least as massive as Jupiter. Meanwhile, the brown dwarf it orbits is about 30 times as massive as Jupiter. Hoy said:

This system is somewhat hard to define using solar-system-based words like ‘planet’ and ‘moon.’ The exosatellite is clearly massive enough to be a planet, but it does not orbit a star, though it orbits an object that orbits a star. Being the third wheel in this system makes us want to call it a moon, even if it is nothing like the small, rocky moons we have in our system.

The name game

Humans have a need to neatly categorize the things they encounter in the world. But nature is not so rigid. Pluto itself did not change when its classification changed from planet to dwarf planet. And asteroids, comets and meteors are all leftover material from the formation of our solar system under different names.

But naming things – or nomenclature – is part of the scientific process. It’s just not always easy to do. Co-author Alice Zurlo of Universidad Diego Portales said:

We have a clear delineation between the planets and the sun in the solar system, so defining things like moons is simple. In the CD-35 2722 system, where we are blurring the lines between stars, planets and moons, the whole thing becomes more complicated to describe.

Exomoons around exoplanets

Astronomers didn’t confirm the first exoplanet – or planet around a star other than the sun – until 1992. Because they are so small and dim compared to their parent star, they are particularly hard to find. But astronomers long thought they were there. And now we’ve confirmed some 6,000 exoplanets.

So far, it’s been a similar story with exomoons. Astronomers assume there are many exomoons in other stellar systems, just as there are many moons in our solar system. It’s simply a challenge to find them. Astronomers have found exomoon candidates around distant exoplanets, but no confirmation yet.

This candidate exomoon – if it ends up with that label – has strong evidence. It’s causing the brown dwarf that it orbits to wobble. And those wobbles show up in the brown dwarf’s spectra. Zurlo said:

As exotic as it is, this system is truly unique and represents a breakthrough: the first plausible detection of an exosatellite.

Bottom line: Have astronomers found the first exomoon? We think of moons as objects that orbit planets. So what do we call this object, which orbits a brown dwarf?

Source: Planetary-Mass Exosatellite Detected Around a Star’s Substellar Companion

Via ESO

The post Have we found the first exomoon … around a brown dwarf? first appeared on EarthSky.

• Experts have been debating how we should use the moon’s far side. Should we protect it exclusively for science? Or should we open it to commercial activity?
• One side argued the far side of the moon has a unique radio-quiet, dark and stable environment. This makes it an ideal location for future radio astronomy, gravitational-wave research and other studies.
• The other side argued that commercial and scientific activities can coexist under effective international governance. Which side won over the audience? Read on to find out.

The Royal Astronomical Society shared this press release on July 22, 2026. Edits by EarthSky.

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Should we reserve the far side of the moon for science?

What we do on the moon now will set a precedent for preserving parts of the entire solar system as we move out into it, according to astrophysicist and leading space debris expert Jonathan McDowell.

He was speaking during a debate in which experts considered whether we should preserve the far side of the moon solely for scientific endeavors. Or, alternatively, if we should open it to commercial and industrial activity.

McDowell said:

Is the whole solar system up for grabs, or are we going to have nature reserves and science reserves, where we don’t mine all the asteroids and don’t turn all of Mars into a theme park?

A debate among experts

The debate on Tuesday, July 21, 2026, formed part of several sessions on lunar governance during the Royal Astronomical Society’s National Astronomy Meeting (NAM 2026) being held this week at the University of Birmingham.

A panel of eminent astronomers and commercial space professionals were asked to explore a question that is becoming increasingly important as governments and commercial companies prepare more missions to the moon: Should the lunar far side remain a protected scientific environment, or should commercial activity be allowed alongside research?

The argument for science

The far side of the moon presents a unique environment that is radio-quiet and free of artificial light. This is because the moon is tidally locked to Earth. So its rotation on its axis takes exactly as long as its orbit around Earth. These two motions sync up perfectly. Thus, the same lunar hemisphere faces Earth at all times, and the far side of the moon is never exposed to Earth noise.

Astronomers Professor Joe Silk and McDowell argued in favor of preserving the lunar far side. They called it one of the most scientifically valuable locations in our solar system.

As it is permanently shielded from Earth’s radio transmissions, they said it is the only nearby location where radio telescopes could observe the universe without interference from human-made signals. Such observatories could detect faint radio emissions from the cosmic Dark Ages. This is the period after the Big Bang before the first stars and galaxies formed.

They also argued that the far side offers an exceptionally stable environment for future gravitational wave detectors. The moon has no atmosphere, no weather and very little seismic activity compared with Earth. So it could provide an ideal platform for experiments that need to measure extraordinarily small distortions in space-time. These would include studying gravitational waves that give us insights into the origins of the universe.

More arguments in favor of science

The permanently dark lunar night also offers conditions free from the artificial light pollution that increasingly affects optical astronomical observations on Earth.

Silk argued that protecting these conditions now is essential if future generations are to tackle some of astronomy’s biggest unanswered questions. He said:

I think it’s important to preserve the far side for the ultimate science, which will be decades in the future. We have to plan ahead, and the reason is very simply that these are some of the most important questions that humanity has ever posed: Are we alone in the universe, and how did the universe begin?

Silk and McDowell said many of these scientific opportunities could be compromised if the far side becomes developed. Future communications satellites around the moon, landing spacecraft, mining activities and other infrastructure could introduce radio interference, dust, vibration and artificial light. They said these would permanently degrade the unique environment that currently makes the far side so valuable for science.

McDowell said the decisions made over the next few years would set a precedent that shapes humanity’s wider relationship with the solar system. He added:

What we do now and in the next few years to preserve science on the moon is going to be critical not just to the future of science on the moon, but to the future of science and the environment throughout the solar system.

The argument for science and commerce

Those speaking against the motion argued that scientific discovery and commercial activity should not be viewed as mutually exclusive. Nikita Chiu said the debate was about whether ensuring future exploration could be sustained. She argued that commercial investment would be essential if lunar exploration is to become more resilient and less dependent on government funding. Chiu added:

Today’s debate is not to challenge the value of scientific endeavors, but is about understanding how we may sustain exploratory efforts.

Chiu argued that commercial and scientific activities can coexist under appropriate governance. She explained:

An inclusive cislunar economy for the far side of the moon does not need to lead to a ‘Wild West’ situation. I argue that the far side of the moon should not be confined solely for scientific endeavors.

The debate was held ahead of the conference session Protecting the Moon: Governance, regulation and the lunar economy. That session explored how international governance could protect the moon’s radio-quiet regions, dark sky environments and scientifically significant sites while enabling responsible commercial activity and clear rules for future lunar exploration.

How the audience voted

Audience members voted before and after the debate via a QR code about the statement: The far side of the moon shall be preserved solely for scientific endeavors.

Support for the motion increased from 68% before the debate to 76% after hearing arguments from both sides of the panel.

The discussion formed part of a wider program at NAM 2026 examining future governance of the moon. While renewed interest in lunar exploration promises discoveries and commercial opportunities, it also raises questions about whether to protect parts of the moon that offer unique scientific value.

Martin Ward, of the University of Durham, who hosted the evening, convened the debate.

Bottom line: Should the far side of the moon be reserved for science? What we decide now could shape the future of the entire solar system.

Via RAS

Read more: Starlink satellite breaks up, scatters debris

Read more: Probing the Cosmic Dark Ages from the far side of the moon

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Our galaxy flipped after a collision, say astronomers

Astronomers think that some 10 billion years ago, our Milky Way galaxy collided with another galaxy, which they’ve dubbed the Gaia Sausage. And on July 21, 2026, a team of astronomers at the Royal Astronomical Society’s National Astronomy Meeting said that this collision flipped the disk of our galaxy.

The team of astronomers, from Durham University in the U.K., used supercomputer simulations to study how 25 galaxies like our own would have evolved over billions of years. The simulations helped explain how the collision and aftermath resulted in our galaxy’s disk flipping by more than 90 degrees. And, they said, this scenario helps explain why stars in the halo around our galaxy behave the way they do.

The Milky Way galaxy and its clones

Our Milky Way is a spiral galaxy with a central bar. Most of the galaxy’s stars are in the bulge and disk, but there are other stars orbiting in a diffuse halo – a vast, much sparser sphere of stars – around the galaxy’s core and spiral arms.

These stars in the halo come from mergers, over time, with other smaller galaxies. The Gaia mission, which tracked the motions and distances of billions of stars, showed that the Milky Way’s halo is very slowly rotating. But scientists didn’t know why.

This is where the simulations came in. The researchers found that other galaxies with slowly rotating halos had a couple of things in common. First, these simulated galaxies experienced a major head-on merger with another galaxy during their evolution. And second, they experienced a disk flip. These two ingredients appeared to be the keys to creating the slowly rotating halo.

Lead researcher Kirill Batrakov at Durham University said:

We already know that the Milky Way had a massive head-on collision in the past with a galaxy known as Gaia-Sausage-Enceladus (often simply called the Gaia Sausage). So, we think that the Milky Way disk likely flipped in the past.

The Gaia Sausage hit us

This galaxy that hit us was a dwarf galaxy. It was particularly massive for a dwarf galaxy, but it was still smaller than the Milky Way.

Why do scientists call it the Gaia Sausage? Well, after the collision some 10 to 11 billion years ago, our galaxy absorbed the stars of the Gaia Sausage. The leftover stars from this galaxy now take long, elliptical paths – sausage-shaped, if you will – about the Milky Way’s center.

Simulated galaxies with and without a flip

In the images below, we see two simulated galaxies. The first set of simulations are of a galaxy researchers call Halo 18. This galaxy underwent a disk flip. The one below it – simulated galaxy Halo 6 – did not have a collision or disk flip.

Insight into galactic evolution and dark matter

A collision and disk flip gives astronomers more insight into the history of our own galaxy. And it also provides insight into other galaxies similar to ours. Batrakov said:

Because we live inside the Milky Way, we can study it in more detail than any other galaxy, which makes it a key testbed for understanding galaxies more broadly.

Not every galaxy experiences a disk flip. But now it seems the Milky Way experienced at least one in the past. Batrakov said:

Finding that its disk flipped adds a new chapter to that story, one we must account for when placing the Milky Way in a broader context of other galaxies. What excites me the most is that this complex history can be reconstructed just from present-day observations.

And the insight could extend to the elusive substance astronomers call dark matter. Astronomers have already known from earlier measurements of the movements of our galaxy that an invisible dark matter halo surrounds the Milky Way. In fact, dark matter makes up 90% of the mass of our galaxy.

The new study found that the starry halo rotating around the Milky Way is closely linked to the rotation of its dark matter halo. So this suggests that the Gaia Sausage remnants, along with other smaller galaxies that collided with us, may have evolved in step with the dark matter halo.

Bottom line: Our galaxy flipped after a collision with a dwarf galaxy 10 billion years ago, changing the Milky Way’s evolution, new simulations suggest.

Via Royal Astronomical Society

Read more: Did galaxy-killing wind shape the early universe?

Read more: The black hole or galaxy: Which came 1st?

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One more image from Mars!

On July 17, 2026, NASA released one more image – really a composite of 13 images – as the Psyche mission swung past Mars for a gravity assist.

The Psyche mission, on its way to asteroid 16 Psyche, flew past Mars in May. The images above are a collection from between May 2 and 15, 2026, as the space probe grew nearer to the red planet. On Psyche’s approach, the angle of the sun meant the planet appeared as a lit crescent.

The team has also put together a time lapse of Psyche’s encounter with Mars. We get to see the approaching ruddy crescent, a view looking down at Martian craters, and then the red planet with its south polar ice cap receding from view as the space probe heads off toward the asteroid belt. It’s stunning! Watch it below.

Images of the Psyche mission flyby of Mars

The Psyche mission successfully completed its flyby of Mars on May 15, 2026. Mars gave the spacecraft a 1,000-mile-per-hour (1,600-km-per-hour) critical gravity assist.

It also moved its orbit by about 1 degree. So the spacecraft is now successfully it on track toward the asteroid 16 Psyche. See some of the new images of the flyby below.

Because of the angle of Psyche’s approach, Mars appeared first as a crescent. Then it saw a more fully lit Mars as it flew away.

Psyche mission flyby of Mars

The Psyche spacecraft, launched in 2023, is headed toward a rare metal asteroid, also named Psyche (16 Psyche, the 16th asteroid discovered). It will arrive in 2029. But in order to get out to the asteroid belt, the spacecraft made a close flyby of Mars to adjust its direction and pick up a boost of speed on May 15, 2026.

Psyche came within 2,800 miles (4,500 kilometers) of the red planet’s surface. That’s closer than Earth’s geostationary satellites. The spacecraft was traveling at 12,333 mph (19,848 kph).

The maneuver used Mars’ gravity as a “slingshot” to accelerate the probe and tilt its trajectory toward its final destination, the metal-rich asteroid 16 Psyche.

An early Psyche image of Mars was the one below, from May 3. In the image, Psyche was still about 3 million miles (4.8 million km) away.

Does Mars have a ring?

Astronomers think Mars might have a faint, dusty ring. The ring would be the result of micrometeorites striking Mars’ two moons, Phobos and Deimos, and ejecting dust into orbit around Mars. So there’s a chance that data from Psyche could reveal this dusty ring around Mars. The sun-Mars-Psyche alignment might allow the sun striking the particles to scatter light, and image processing could pick up the ring.

Why fly past Mars?

While most flybys are planned to give a spacecraft a boost of speed, this flyby is also important to slightly change the spacecraft’s trajectory. The orbit of asteroid Psyche is skewed by about 3 degrees from the plane of the solar system. So in order to get to the asteroid Psyche, the Psyche mission must adjust its trajectory by a little bit.

More about the Psyche mission and asteroid

Some scientists think the asteroid Psyche is a failed planet. Perhaps, as the nascent planet formed, something struck it and stripped off the outer layers, leaving behind the metallic core. If so, then some estimates put the massive, metal-rich object’s worth at $10,000 quadrillion. That’s more than the entire economy of Earth.

However, a 2021 study from the University of Arizona said asteroid Psyche might not be as metallic or dense as scientists once thought. Instead, these scientists said:

Rather than being an intact exposed core of an early planet, it might actually be closer to a rubble pile.

Who’s right? That’s what the Psyche mission hopes to discover when it arrives at the asteroid in 2029.

Bottom line: NASA released a composite image of Mars lit like a crescent as the Psyche mission flew by for a gravity assist. You can also watch a stunning time lapse of the whole flyby here.

Via NASA

Read more: Ancient lake on Mars? Rover finds strong new evidence

Read more: New meteor shower from an asteroid being eroded by the sun

The post Another new Psyche mission flyby image of Mars first appeared on EarthSky.

• LHS 1140 b is a super-Earth exoplanet 48 light-years away. It orbits in the habitable zone of its red dwarf star.
• Scientists have just found evidence that this world has an atmosphere. The evidence comes from helium leaking from the planet into space.
• The researchers estimate the atmosphere is over 3 billion years old. More observations are needed to know the atmosphere’s composition.

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1st detection of atmosphere on rocky exoplanet

For the first time, astronomers have found strong evidence for an atmosphere on a rocky exoplanet in the habitable zone of its star.

The planet, LHS 1140 b, is a super-Earth planet about 48 light-years from us. LHS 1140 b orbits a red dwarf star within the so-called habitable zone. Being in this zone doesn’t necessarily make a planet fit for life. The habitable zone is simply the region around a star where temperatures would allow water to remain liquid, which is crucial for life as we know it.

The researchers, led by the Center for Astrophysics | Harvard & Smithsonian in Cambridge, Massachusetts, said on July 16, 2026, that they detected helium escaping from LHS 1140 b. And this kind of helium escape also happens in the atmospheres of Earth and other planets.

LHS 1140 b is 1.73 times the radius of Earth and 5.6 times Earth’s mass. The researchers say that’s consistent with an Earth-like bulk along with a lower-density part, such as an atmosphere or a high abundance of water.

The planet has an estimated equilibrium temperature of 116 degrees Fahrenheit (47 degrees Celsius).

The researchers published their exciting peer-reviewed results in Science on July 16, 2026.

A major milestone

The discovery is a major milestone in the study of rocky exoplanets. That’s because an atmosphere is essential for life as we understand it. Lead author Collin Cherubim at Harvard University said:

An atmosphere is essential for a planet to support life as we know it. This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star.

Co-author Robin Wordsworth added:

20 years ago we wondered whether other terrestrial-type planets even existed. Then we learned they’re common, and found some in the habitable zone. The next question was whether any of them had managed to keep an atmosphere. Now we know at least one has.

Cherubim and his colleagues were testing their theoretical model of LHS 1140 b. The model predicted that the planet would have an atmosphere, with helium escaping from the upper atmosphere into space. The researchers used the Warm Infrared Echelle (WINERED) Spectrograph on the Magellan Clay Telescope at Las Campanas Observatory in Chile for their observations of LHS 1140 b.

And, in fact, they observed both known planets of the star LHS 1140. Both LHS 1140 b and LHS 1140 c transited their star on the same night. The researchers saw no evidence of an atmosphere on LHS 1140 c, which is smaller and more heavily irradiated by its star. But LHS 1140 b was a different story.

Escaping helium points to an atmosphere

The researchers found helium escaping from LHS 1140 b. This kind of helium escape has been seen before on some planets, including Earth. Helium, a very light gas, will move to the top of an atmosphere, where it will start leaking into space. And the data was solid. David Charbonneau, head of the Harvard Department of Astronomy and astronomer in the Center for Astrophysics | Harvard & Smithsonian, said:

Collin analyzed the planets we knew about and predicted that this one would have a helium atmosphere. Then he organized telescope time, got the data and the detection was statistically rock solid.

The X-ray data from Magellan Clay explained the rate at which the planet lost its helium. This is due to X-ray radiation from the host star. Therefore, the X-ray data proved the rocky object must be replenishing its supply of helium. If it wasn’t, there would be no helium remaining in the planet’s atmosphere.

Notably, the researchers detected the helium escape in 2024 but not in 2025. This indicates that the atmospheric escape process is variable. It also means the atmosphere likely no longer contains any primordial hydrogen in its atmosphere. That’s good, since it hints that the atmosphere is more complex and evolved, like on rocky planets in our solar system, including Earth. Other gases and water would be below the top helium layer.

An ancient atmosphere

The researchers say that the atmosphere has likely survived for more than 3 billion years.

Astronomers had found that some other rocky exoplanets don’t have atmospheres. This was cause for a bit of pessimism among scientists. As Jason Dittmann at the University of Florida noted:

We were getting to the point in the field where maybe all of these planets don’t have an atmosphere, and we need to look at ones around sun-like stars instead of smaller stars. And then finally here is actually one with an atmosphere, and it happens to be the one that I had spent so many hours working on.

LHS 1140b is one of the current selected targets under the Rocky Worlds Director’s Discretionary Time (DDT) Program. Rocky Worlds DDT is a joint program for the James Webb Space Telescope and the Hubble Space Telescope that is dedicated to finding evidence of atmospheres on rocky exoplanets orbiting dwarf stars.

We still don’t know what the rest of the atmosphere, below the upper helium layer, is composed of. That will require additional observations to figure out. As Cherubim noted:

This has been a model validation, and hopefully it’s just the first of many more observations to come.

Bottom line: Scientists have found an atmosphere on rocky exoplanet LHS 1140 b. The super-Earth planet, 48 light-years away, is in the habitable zone of its red dwarf star.

Source: Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone

Via Center for Astrophysics | Harvard & Smithsonian

Via University of Florida

Read more: New habitable exoplanets model narrows down search for life

Read more: Habitable exoplanets could exist around nearby stars

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