Hello, friends! Welcome to Our Place in Space: A to Z! For this year’s A to Z Challenge, I’ll be taking you on a partly imaginative and highly optimistic tour of humanity’s future in outer space. If you don’t know what the A to Z Challenge is, click here to learn more. In today’s post, J is for…
Someday, I’d like to help dig up dinosaur fossils. That’s apparently a thing pretty much anybody can volunteer to do. Someday, I’d also like to live on Mars. In the distant future, it may be possible to do both of those things. Places like Jezero Crater on Mars may be full of ancient Martian fossils!
If you look at satellite images of Jezero Crater, it’s pretty obvious it used to be full of water. You can see what appears to be a dried-up river bed snaking its way across the Martian landscape. Where that river meets the crater, there’s a breach in the crater wall and a large river delta where the river would have spilled into the crater basin.
Right now, NASA’s Perseverance Rover is driving around that river delta, scoping the place out, examining the sediments and clays found in the region.
Okay, I may have taken some creative liberties with the cartoon above. If life ever did evolve on Mars, it would have been short-lived. All of Mars’s lakes, rivers, and oceans would have dried up fairly early in the planet’s history. It is highly unlikely that anything as complex as fish or seaweed could have developed, and there certainly wouldn’t have been anything as awesome as a Martian dinosaur.
But in places like Jezero Crater, simple microorganisms could have been plentiful. These microbes may even have joined together, creating larger structures like the bacterial mats we sometimes find here on Earth. That’s kind of icky, I know, but it could have happened, and those bacterial mats may still be there, preserved as fossils beneath all that red dust.
I don’t expect questions about life on Mars (past or present) to be answered any time soon. Even if one of our Mars rovers did stumble upon something that looked like a fossilized bacterial mat, there would be scientific debates for years—decades, even—over what that fossil-looking-thing really is and what it’s presence on Mars really means. We’ve been through this before, when scientists found “bacteria shaped objects” inside a Martian meteorite. Something can look like a fossilized bacterium, and yet not be a fossilized bacterium.
But someday in the distant future, we will know, one way or the other, if life ever existed on the Red Planet. And perhaps in that distant future, humans living on Mars will volunteer to help dig up fossils in Jezero Crater, or other places very much like it.
Want to Learn More?
Here’s an interactive map from NASA showing the Perseverance Rover’s current location. You’ll have to zoom out a little to see all of Jezero Crater. If you do, you’ll see that the dried-up river (marked Neretva Vallis) and river delta I mentioned are pretty obvious.
And here is a NASA press release from a few years back, announcing Jezero Crater as the Perseverance Rover’s landing site and explaining why the crater was selected.
Also, here’s an article from Space.com about that Martian meteorite I mentioned, the one with those “bacteria shaped objects” inside.