Reading view

Did Venus eat its own moon?

8 September 2026 at 22:00

Scientists may finally know why Venus, Earth's twin, lacks a moon, finding that the hottest planet in the solar system may have consumed its own natural satellite.

Venus is often referred to as Earth's twin due to its size, mass, rocky composition, and distance from the sun, but there are some glaring differences between the two planets. Aside from Venus' blisteringly hot temperature, which could melt lead, incredible surface pressure, violent high-speed winds, and clouds of sulfuric acid, one of the key differences between Earth and Venus can be seen from afar. While our planet has a constant companion in the form of the moon, Venus lacks a moon of its own. In fact, the only solar system planets lacking moons are Venus, the second planet from the sun, and Mercury, the closest planet to the sun.

One question that scientists have puzzled over for years is whether Venus always lacked a moon, or if the hottest planet in the solar system once had a natural satellite and somehow lost it. Now, a team of researchers may have arrived at an answer, determining the fate that would have befallen a hypothetical moon orbiting Venus.

"I have always had a fascination with moon formation and evolution in the solar system, and particularly with Venus since my research is centered around its evolution and potential for past habitability," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "Venus is Earth's twin, and both are nearly identical in size, mass, and composition. However, Earth has a large moon, and Venus has no moon at all, not even a small captured satellite.

"Venus undoubtedly experienced large impacts, just as Earth has, and so has had as much, if not more, opportunity to form a moon similar to what we see in our own skies."

Kane and colleagues constructed a simulation to test their ideas of what could have become of the Venusian moon.

"The work involved going back to fundamental physics and creating the simulation from the ground up, which I validated by ensuring I could reproduce the evolution of the Earth-moon system," Kane said. "The moment I realized that our model provided a complete explanation for Venus not having a moon was an exciting one!"

Did Venus consume its own moon?

The team modelled a gravitational tug-of-war between Venus, a hypothetical moon, and the sun, following this forward over billions of years.

"This is the same physics that governs our own moon, which is slowly drifting away from Earth. We ran the calculations across a wide range of possibilities for how fast Venus was spinning and how massive its moon might have been, using two independent mathematical descriptions of how tides work," Kane explained.

The researcher said that this was done so the conclusions reached wouldn't hinge on one set of assumptions. They found in most cases a Venusian moon would not drift safely outward the way ours does. Instead, the modelling showed that a moon orbiting Venus would eventually reverse its course and spiral inward, causing it to be torn apart by the planet's gravity.

Kane and colleagues found that possessing an intimidating size wouldn't guarantee a Venusian moon's survival, either.

"An interesting aspect is that a heavier moon is destroyed faster, since a massive moon would drain Venus's spin so efficiently that it hastens its destruction," Kane added.

A striped brown sphere against a black background — Venus as seen from Earth may look peaceful, but up close, it is a hellish world that may have destroyed its own moon. (Image credit: Starry Night)

But are there any circumstances under which a Venusian moon could have survived?

"Survival came down to two main things: Venus had to be spinning fast when the moon formed, with a day shorter than about 12 hours, and the moon couldn't be too massive, up to roughly the mass of our own moon," team leader Stephen R. Kane of the University of California, Riverside told Space.com. "In that narrow window, the moon migrates outward and stabilizes, much as Earth's did. Outside that range, the moon is unfortunately doomed to be consumed by Venus.

"So a surviving moon would have had to be modest in size, orbiting a rapidly spinning early Venus, which are conditions that don't match what we think early Venus was actually like."

We may never conclusively know if Venus has indeed destroyed its own moon, as Kane thinks that collecting direct evidence from astronomical observations will be very difficult.

"Finding direct observational evidence is pretty tough. A moon lost billions of years ago would leave little to no direct trace we can point a telescope at today, so we can't observe the event itself," Kane said. "However, there are indirect avenues. For example, if a moon was destroyed and its debris rained down on Venus, it could have left a chemical fingerprint in the planet's surface or atmosphere, and upcoming missions to Venus, including NASA's DAVINCI (Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging) probe, will measure atmospheric composition in detail."

If missions such as DAVINCI could help us develop a better understanding of the Venusian interior, then this would also improve the models such as the one used in this research. That is because the outcomes of such models depend on properties of Venus's interior, which aren't currently well understood.

"There's a broader test beyond our solar system because our results predict that slowly rotating, Venus-like planets around other stars should generically lack large moons, so as astronomers begin searching for moons around exoplanets, that's a prediction that can eventually be checked against real data," Kane said.

A spherical silver spacecraft against a fiery orange background — An artist's depiction of the DAVINCI probe nearing the surface of Venus. (Image credit: NASA's Goddard Space Flight Center)

Kane and colleagues don't intend to rest on their laurels while further data from Venus or even Venus-like exoplanets are delivered. They have plenty to work on in the meantime.

"There are numerous implications of our work that I would like to explore further. These include the compositional and atmospheric effects of a Venusian moon consumption event that may be testable now," Kane concluded. I would also like to explore similar effects for Mercury and Mars, and conduct further studies on exoplanet cases where such moon collision scenarios may have occurred."

The team's research is available as a pre-peer-reviewed paper on the repository site arXiv.

Scientists Discover How Extraterrestrial Life Could Thrive In the Harsh Acidic Clouds Surrounding Venus

The Debrief

By: Ryan Whalen

1 September 2026 at 13:12

A new theoretical kind of extraterrestrial life could survive the harsh acid clouds of Venus, according to MIT researchers.

Despite longstanding conceptions that Venus would be too deadly for even the hardiest of extremophiles, new evidence suggests a rethinking of life from the ground up may be in order. The work was revealed in a recent paper published in the Proceedings of the National Academy of Sciences, which describes how extraterrestrial life could form from peptides to thrive only in such a hostile environment.

Based on recent evidence, it may be time to cast a wider net in the search for extraterrestrial life and look at planets that bear little resemblance to Earth.

The Brutal Venusian Environment

“We really don’t know the full extent of what planet archetypes are out there,” said senior co-author Sara Seager, the Class of 1941 Professor of Planetary Sciences in the Department of Earth, Atmospheric and Planetary Sciences and a professor at MIT’s departments of Physics and of Aeronautics and Astronautics. “We’re seeking exoplanets that might be a true Earth twin, but what if they’re all Venuses? Our findings definitely open up a whole range of possibilities.”

About 30 to 40 miles above Venus’s scorching surface, which reaches temperatures close to 900° F, lies a pocket of milder temperatures that some scientists think may be conducive to life. However, this region’s heavy cloud cover poses its own challenges. Instead of being composed primarily of water, the clouds on Venus are 98% sulfuric acid, which is strong enough to dissolve metals and would kill any known life on Earth.

While traditional astrobiological thinking held that this would be far too extreme for complex biological molecules to hold together, new evidence is overturning that idea. Recent work at MIT suggests that peptides can endure such challenging conditions, maintaining their stability and adopting shapes useful to biological processes.

“If peptides find their way to that cloud layer of concentrated sulfuric acid, they will stay and be stably preserved in that cloud of droplets,” said senior co-author Mei Hong, an MIT professor of chemistry and one of the senior authors of the new study. “And once these macromolecules have a defined three-dimensional structure, they can potentially have a function.”

Seeding Extraterrestrial Life

Following the concept of panspermia, which holds that the building blocks of life are transmitted throughout the universe on meteoroids, asteroids, and comets, the researchers investigated whether any building blocks could survive the Venusian conditions to give rise to extraterrestrial life.

Work began in Seager’s lab in 2020, studying how biological molecules could endure the stress of such an acidic environment. With nuclear magnetic resonance spectroscopy, they analyzed the structures of molecules in sulfuric acid solution. Surprisingly, nucleic acids, lipids, and amino acids all maintained their integrity under acidic conditions.

The next step was to investigate whether peptides could likewise hold their integrity and also assume useful biological shapes. They were surprised to find how resilient the peptides were, holding on for weeks at a time. Ironically, the lack of water in the environment could be a blessing, as without it, the hydrolysis reaction that breaks down peptides cannot occur.

“Without water, an acid that you would consider a harsh solvent suddenly is not as menacing as one might think,” Hong said.

New Concepts in Extraterrestrial Life

Additionally, the sulfuric acid molecules acted as scaffolds, allowing biologically useful shapes to form that otherwise wouldn’t, such as omega loops, which are found in some naturally occurring proteins on Earth but not typically in peptides.

“What hadn’t been known is that peptides can survive so well and have specific three-dimensional shapes in an acidic environment,” Hong explained.

Follow-up work will take these ideas even further, synthesizing a DNA alternative called PNA, made from peptides. Their existing work shows that a single PNA strand is stable in sulfuric acid, but the new research will attempt to recreate DNA’s double-strand structure with peptides. They also plan to investigate whether long peptides can hold omega loops under these acidic conditions.

Based on their results, extraterrestrial life could easily be hiding in environments highly divergent from anything seen on Earth. Continued investigation may reveal that rather than being poisonous, environments like Venus may be the only places certain lifeforms could exist.

The paper, “Peptides Adopt Stable Omega-loop Structures in Concentrated Sulfuric Acid,” appeared in Proceedings of the National Academy of Sciences on September 4, 2026.

Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.