Katie Stack Morgan

The first ones we found we called poppy seeds because they were little dark flecks in the rock that were a unique mineral called vivianite.

And you would be forgiven for not knowing the mineral vivianite because I did not know the mineral vivianite when we discovered it.

When you find Vivianite on Earth, sometimes you find it associated with decaying organic matter here on Earth, and so involved in life and associated with microbial activity.

And we call them leopard spots because they really look like leopard spots.

We have this red rock and these small features, they're round, that have dark gray rims and then kind of a bleached white inner center.

But one of the reasons why we think life might have been involved in the formation of these features is because the particular minerals involved in these reactions, they tend to form most easily either at really high temperatures or with life to help those reactions move along.

And based on what we know about these rocks, we don't necessarily think that they experienced really high temperatures.

So if you can't explain these minerals with heat,

One of the most reasonable alternative explanations is life.

And we're not sure that life was there.

You know, that's still a question.

And that's why we call these features potential biosignatures.

And the potential is doing a lot of work here.

But this is probably the first time that we've really had life as a truly compelling alternative hypothesis and one that is really worthy of consideration.

So Perseverance's science mission continues, and we waved goodbye to Chiava Falls after spending a couple of months there and said, OK, we have a whole new set of rocks to explore.

So we spent the first three and a half to four years of the mission looking at rocks, studying rocks that were inside Jezero Crater.

And that means that they are most likely younger than the formation of the crater itself.

But we've now transitioned to exploring the crater rim of Jezero and the rocks even beyond the crater rim.

And so these rocks are older than the formation of Jezero.

And these really old rocks are probably amongst the oldest rocks in the solar system.