Lynn Carter

And when people go back and again try and compare with those obliquity cycles, people think all of the CO2 would have been in the atmosphere only 600,000 years ago.

And this is so much CO2 that you can actually raise the density of Mars' atmosphere by about 10 times its current density.

And so that has big implications for whether or not you can have liquid water.

So suddenly, liquid water could be slightly more stable, although not immensely stable, it turns out.

So, but this was very interesting for Mars climate too because now we know that there's these deposits of CO2 and as the obliquity flips back and forth you can release huge amounts of gas into the atmosphere and then it can condense out in the poles once it's colder again.

So that's a very different situation and even if people thought that sure the polar caps go away and they come back and they go away because they're pretty young, being able to see that this is happening on pretty short time scales is sort of remarkable.

Another thing that we've been able to do with the poles, we have so much data that we've actually been able to do 3D imaging.

So we use some seismic techniques and software to take all of the data that we have and make a 3D image of the pole.

So we actually have this box now for both poles and then you can cut slices through and look for buried features in the ice.

So there's different things that you can see.

First of all, you can see the layering a lot better in this because it actually integrates all of the information that you have from all of those tracks

into one image.

So it's a lot clearer to look at actually than the individual radar grams or radar profiles.

And one thing that we saw was a lot of buried craters.

So there's all these circular features here, here, and a couple of little ones over here.

This is one that we know about what it is.

And this one we know about too.

But finding buried craters is interesting because that allows us to age date the surface better.

And so the team that worked on this, Fritz Voss and some of the rest of our team, they went and looked and counted these craters and compared them to the surfaces that are around the pole.

And what they find is that the surface that looks like it's underneath the ice cap has very similar craters to the population of the terrain that's surrounding it.