Martian sweat stains. Is there to be no privacy in the universe? 
djm
But doesn’t that just mean “something, likely a liquid” moved? Why does it have to be water?
Water’s not my favourite either, i like beer better 
“…O!Water cold we may pour at need
down a thirsty throat and be glad indeed;
but better is Beer, if drink we lack,
and Water Hot poured down the back…”
Boy, I’m really behind the times. I read the little article that goes with the photo and it said that it has been known for years that there is frozen water on Mars. That was news to me! 
All day I face the barren waste
Without the taste of water
Cool water
Old Dan and I with throats burned dry
And souls that cry for water
Cool, clear, water …
djm
Just some food for thought: the three elements needed for life (as we know it) are oxygen, liquid water, and energy (not neccessarily solar.) There is no place on Earth where, if these three criteria are met, you will not find life.
Now in this case: if that is indeed evidence of liquid water, and that water has oxygen in it, and there is sufficient energy from solar radiation or other some other source, there is a possibility for life. And even if there is no life present, it could serve as an indicator of where to start terraformation of Mars.
ACK!!!
too serious!
necessity is a mother
Same thing happened on my windshield the day after I bought my new car.
I sure hope that bird was on the way out of the gallaxy.
Sorry. Being silly 24/7 is difficult and I’m bound to slip up on occassion.
If necessity was a mother we would have to invent her.
If invertion was a necessity we would have to moth her.
If mother was an invention we would have to ressucitate her.
djm
Silly me I forgot that plants breath CO2 rather than O2. Also, I neglected to mention organic compounds (food).
THere are “aquifers” of highly concentrated brines in the subsoils of Mars, and the do occasionally “leak”. The thing about liquid water on mars is that it is not stable on the surface, so you while you can get brief flows of liquid water, they don’t remain in that state very long. The problem for life on mars is finding permanent areas of liquid water, which there are none, as far as anyone knows.
Because we know that the surface temperature on Mars can be high enough to support liquid water, and we know that there is water ice on Mars. There is no such thing as liquid carbon dioxide, the other candidate for “ice” formation on Mars, so it can’t be that. The deposits don’t have the attributes of lava, the only other realistic candidate for a fluid on the surface.
Oxygen is certainly not required for life. There was no free oxygen in the Earth’s early atmosphere: all the oxygen in the atmosphere has been put there by photosynthetic organisms. So life first got going on Earth without oxygen. Even today there are facultative and even obligate anaerobes in the form of specialised bacteria and fungi. That is, organisms that can do very well without oxygen. By far the most important of these is yeast, without whose oxygen-free activities I would not have this glass of superb Chilean red in front of me.
Not so. Plants require oxygen for aerobic respiration as do animals, but green plants by day obtain carbon dioxide by diffusion and make more than enough oxygen for their modest respiratory needs, sedentary as they are (good thing too, as we need their excess). By night they are like us: they need to obtain oxygen from their environment, which they obtain by diffusion through their stomata or their outer layers. You could call this “breathing.” So, to summarise, green plants need oxygen 24/7, as do animals, but during the day they provide for their needs by photosynthesis, for which they require carbon dioxide. At night, they are just like us, only slower, and they produce carbon dioxide.
“Food” we’ll leave for later.
Doesn’t look like water to me - just a long drawn-out avalanche.
And this discussion of life as we know it.
Well, that says it all.
I imagine there may be things “out there” that “scientists” can’t even imagine imagining yet.
I feel a Rumsfeldt soundbite coming on…
To boldly go where no one has known what they don’t know before.