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.
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?
ESA image release