We’ve detected liquid water plumes spraying out of Enceladus, so yes, we’ve directly observed liquid water elsewhere.
The big discovery on Mars of liquid water existing on the surface is important because it’s the only extraterrestrial water we can get to and examine easily. As liquid water is the best environment for microbial life, finding it on the surface makes it a lot easier to sample than digging through kilometers of ice.
What we don’t know is what the origin of the water is. There’s a chance it’s a water cycle that goes from absorption to freezing, then eventually collecting as a liquid when the temperature warms up, oozing out of the dirt, evaporating or sublimating away, repeat ad nauseum. I would think it more likely that water like that would be sterile.
On the other hand, it could be springing out of underground aquifers when the ground warms up enough for it to be able to seep through the ground. In that case, that would be an interesting place to look for life.
There is an agreement to avoid contamination, but it doesn’t completely make it impossible to examine this water. We’d just need to send a probe that is truly sterile, rather than just “pretty clean”. The current Mars landers and rovers were only decontaminated to a “pretty clean” standard (assembled in a clean room and wiped down with alcohol), but they’re definitely not sterile.
I’m not sure the absorption-freezing-melting-evaporating cycle is such a problem by itself. If the same kind of water existed on Earth, you can bet there’d be soil microbes, algae, wind-borne bacteria, something, taking advantage of it. When it got dry, they might go into some kind of dormant cyst form until they got wet again. A long dormant phase is probably necessary for any life that would be living on today’s Mars, anywhere.
Of course, there’s no such guarantee on Mars. It’s a pretty inhospitable environment for life to originate in and there’s a lot of other negatives (thin atmosphere, low temperatures, etc). Still, if life originated at some point in the past, or if Earth life was ever transplanted from meteorites, then it might be hanging on in a place like this.
Here’s my question: haven’t we been through this with Mars already?
They found damp streaks in the dirt. Didn’t we already find damp streaks in the dirt? Or is it a case that the previous streaks were possibly damp, or maybe just shadows, but these were are sure are damp?
Seems like a huge kerfluffle over what I thought we already knew.
Maybe, maybe not. If we did find life on Mars, we’d want to know whether it originated independently of the life we know, or if life was carried from one world to another.
It would be damned confusing.
One of the Apollo missions recovered the arm from a lunar lander. It had microbes on it. It is not known it they survived on the moon from Earth, or if the arm was contaminated upon recovery. They want to be careful about this sort of thing.
The same microbes are on Earth and Mars!
Etc., etc., etc.
:smack:
This is just further information. It’s moved the idea from “a likely explanation” to “confirmed observation.”
As I understand it, the streaks were first observed in 2010 thanks to higher-resolution imagery that made the visible for the first time. Water was suspected from the start, but it’s only recently that further analysis confirms hydrated salts in the soil and proves that water is the explanation.
Its my impression that at one time Mars was pretty darn nice. Plenty of water, a nice atmosphere, and reasonable temps.
This phase lasted a few hundred million years at least.
Then things slowly got worse.
Given that the simplest life on Earth seems to have appeared about a soon as things cooled down enough, which implies that simple life will arise when given half a chance, basic life arising on Mars doesn’t seem particularly far fetched.
The real question, at least in my mind, is did early Mars life manage to continue evolving enough to keep up with the ever worsening conditions on Mars and is it still alive today? And how complex did it manage to get if it did survive?
Yeah, I was thinking of it in terms of life being unlikely to originate there in today’s circumstances, but that the current conditions could theoretically support some kind of life that originated elsewhere/elsewhen.
And hopefully, discoveries like this will help us refine our image of ancient Mars.
