A Crater Pretending to be a Tree Stump

An image taken by the ESA / Roscosmos ExoMars Trace Gas Orbiter reveals a water-ice heavy crater that looks surprisingly like a tree stump.

Beth Johnson
2 min readFeb 3, 2022


IMAGE: This feature could easily be mistaken for a tree stump with characteristic concentric rings. It’s actually an impressive birds-eye view into an ice-rich impact crater on Mars. Tree rings provide snapshots of Earth’s past climate and, although formed in a very different way, the patterns inside this crater reveal details of the Red Planet’s history, too. The image was taken by the CaSSIS camera onboard the ESA/Roscosmos ExoMars Trace Gas Orbiter (TGO) on 13 June 2021 in the vast northern plains of Acidalia Planitia, centred at 51.9°N/326.7°E. CREDIT: ESA/Roscosmos/CaSSIS

This image looks like a tree stump, down to the rings. There are lots and lots of seemingly concentric rings, a dark outer rim… and yes, the entire image says tree stump.

Except that it’s not a tree stump. It’s a crater on Mars.

This fantastic image was taken by the CaSSIS camera on the ESA/Roscosmos ExoMars Trace Gas Orbiter spacecraft back in June of last year. It’s located in a region called the Acidalia Planitia in the northern hemisphere. And, just like tree rings, the rings in this crater tell the history of its creation and life.

There are deposits in the middle of the crater that likely have water-ice in them, and as the seasonal temperatures change, that water-ice undergoes expansion and contraction, causing fractures to form in the surface. Those water-ice deposits were laid down much earlier in Mars’ history when the tilt of the planet’s axis was greater and season differences were larger. Mars’ axial tilt has changed a lot over millions of years, affecting how water and ice deposits were distributed on the surface, leading to a lot of the features we see today.

And today, I guess we see a tree stump?

More Information

ESA image release

This story was written for the Daily Space podcast/YouTube series. Want more news from myself, Dr. Pamela Gay, and Erik Madaus? Check out DailySpace.org.



Beth Johnson

Planetary scientist, podcast host. Communication specialist for SETI Institute and Planetary Science Institute. Buy me a coffee: https://ko-fi.com/planetarypan