View larger. | Here’s a region of cracks on Venus, 2nd world outward from our sun. They might have formed on an ancient seafloor, scientists say. Image via Earth and Planetary Science Letters (2026) (CC BY 4.0).
- Venus is extremely hot and dry on its surface. But scientists think it once had much more water, perhaps even oceans.
- Large networks of polygonal cracks cover Venus’ surface in low-lying areas. A new study says they might have formed in seafloor mud as the water evaporated.
- It’s still a hypothesis right now, but it would support other studies postulating ancient oceans on Venus.
Polygonal cracks on Venus: How did they form?
Much of Venus’ surface is covered in long cracks. And scientists are still debating how they formed. One possible explanation has been volcanic rock that cooled and contracted to form the cracks. But there’s another – and more exciting – possibility. Some of the cracks might have formed in seafloor mud. That’s what a team of researchers from University of London and Imperial College in the U.K. say in a new paper titled The Lost Oceans of Venus.
These vast, polygonal cracks are found in low-lying regions of Venus. And they do look very similar to ones in seafloor mud on Earth. Thick layers of waterlogged clay get buried, compacted and squeezed dry over time. Did the same thing happen on Venus?
The intriguing peer-reviewed findings were published in Earth and Planetary Science Letters on July 29, 2026.
View larger. | Here are the 6 types of cracks identified by the researchers. These cracks are found in low-lying areas on Venus. Image via Earth and Planetary Science Letters (2026) (CC BY 4.0).
View larger. | This diagram depicts the process of how the Venus cracks might have formed. Oceans evaporated, leaving salts behind. Mud on the former seabed dried up, creating the polygonal cracks. Image via Ghail et al./ Earth and Planetary Science Letters.
View larger. | This radar image of Venus’ surface, showing this cloud-covered world without its cloud cover, is a composite of data from NASA’s Magellan and Pioneer Venus Orbiter spacecraft. So we see Venus’ formerly hidden surface is tortured, with many cracks, valleys and volcanoes. Image via NASA/ JPL-Caltech.
6 types of cracks
Venus orbits the sun one step inward from Earth. Its cloud-covered surface has created a runaway greenhouse effect on the planet, giving it surface temperatures averaging roughly 464°C (867°F). So it’s hot enough on the surface of Venus to melt lead! And as a result we tend to think about Venus as a blazing hot world on its surface, which is also known to have features resembling volcanoes. But oceans on Venus? Could have happened?
The cracks might be evidence that it’s possible.
There are various types of cracks found on the surface of this neighboring world. One of them is composed of polygon shapes, in low-lying plains. Each polygon is about 1 to 2 kilometers (0.6 to 1.2 miles) across. The researchers then further divided these polygons into six distinct types. And, they say, the patterns overall are much more similar to cracks in dried-out seabeds than to cracks formed by volcanoes.
Similar cracks on Earth can be found in the Mediterranean Sea. A long time ago, almost 6 million years, it almost completely dried up. As the water gradually evaporated, it left behind thick salt deposits and cracks, like what we see on Venus.
Plus, there are also long, winding channels on Venus called canali by scientists. For some years, scientists have thought that flowing lava formed them. But they’re also similar to channels carved on seafloors.
In addition, wrinkled ridges in the lowlands might be above salt deposits, similar to on Earth.
Another recent study found concentric rings in Venus’ atmosphere! On the left, an unpolarized view of the cloud tops of Venus shows a smooth, regular brightness. On the right, a view in polarized light reveals a set of concentric rings – really, atmospheric ripples – in the dense, high atmosphere. Image via Gourav Mahapatra/ The Planetary Science Journal.
The debate continues
These researchers have presented an interesting, even compelling, scenario. But it’s not proof yet of an ancient ocean on Venus. That will require more study to confirm, or not.
And some other studies have been doubtful about long-lost Venusian oceans.
So the debate will continue, until definitive evidence is found of ancient oceans on Venus. That might require future missions that will study the surface and atmosphere in unprecedented detail.
In another recent study, researchers discovered concentric rings in Venus’ atmosphere, above its thick layers of clouds. The rings are actually waves or ripples, but very ring-like!
Bottom line: Sprawling, huge cracks on Venus have long puzzled scientists. A new study suggests the polygon shapes formed from drying mud on an ancient seafloor.
Source: The lost oceans of Venus
Read more: Venus rings found high above the planet’s thick clouds
Read more: New study says water in Venus’ clouds surprisingly abundant
Paul Scott Anderson
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About the Author:
Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan’s Cosmos. He studied English, writing, art and computer/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
While interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
He has been writing for EarthSky since 2018, and also assists with proofing and social media.