Martian Water - Huge If True
 

"Scientists Discover Giant Reservoir Of ‘Hidden Water’ Just Three Feet Below Mars’ Grand Canyon"

and:

"The water in Valles Marineris may be mineralized, but the scientists believe it is more likely to be in the form of ice. This raises the issue of how the water ice is retained in a region of Mars where it would normally evaporate. "This suggests that some special, as-yet-unclear mix of conditions must be present in Valles Marineris to preserve the water — or that it is somehow being replenished," ESA said." https://blog.physics-astronomy.com/2...ervoir-of.html

that sounds good :)

i just hope its not contaminated with something (chemical/biological) substance.

Tastes like well water if you ask me.

I idly wonder if water actually would "evaporate," if there is no atmosphere out there for the water to "evaporate into."

And – "where the hell did Mars's atmosphere go?" I don't remember about Mercury, but "planets" usually have a very thick one, of some composition or another.

Sundial, I'm old and quite retired now, but I used to teach astronomy and physics. There's lots (and lots and lots...) of misconceptions in your one sentence. Let me explain:
The atmosphere provides pressure to keep the molecules liquid. Reduce the gas pressure and you reduce the temperate at which the liquid will change to gas. Raise the pressure, you raise the temp. at which it changes. Water changes to gas at 212 deg. F when the pressure is what the earth's atmosphere provides - commonly referred to as "1 atmosphere pressure", btw.

As for Mars' atmosphere, that planet is significantly smaller and has about 1/3 the gravity of the earth. It still has an atmosphere, but much less than the earth has (about 0.01 the density and pressure: see https://mars.nasa.gov/all-about-mars/facts/ ). So any liquid water there evaporates at a much lower temp. than on earth.

Once it does that, however, Mars doesn't have the gravity to hang on to that evaporated water forever, so eventually those molecules float off into space.

Now the water underground (on Mars, I mean) is a much different story.

Thank you for the "physics explanation." Nevertheless, it has always struck me as a bit odd that this planet among all the others has virtually no atmosphere. Was this always the case? (Obviously, "poor Mercury can be excused ...") This planet is located beyond our own, farther from the Sun, yet it seems to have no dense gaseous envelope. In fact, "it is entirely noticeable by its absence." What happened here?

Hi sundialsvcs. Allow me to expand on atmospheric considerations a little. Most of the planets are Gas Giants, sort of ALL atmosphere but Jupiter is so massive with so much garvity that it is a possibility that the core is so compressed and cold that it became metallic hydrogen, as hard as that is to imagine. There are rocky moons, some even slightly larger than the planet Mars, but let's focus on the planets for now even though there are similarities with some moons just because of sheer mass.

There are only four rocky planets, the four innermost. Mercury is so small, so gravitationally bound and so hot (on one side anyway) from the extreme proximity to our Sun, that for any practical purpose it essentially has no atmosphere that has ever been detected. Venus has a thick atmosphere but not by dimension, just by viscosity. It's sort of "soupy" and really nasty. Most people think of the Earth as having a vast atmosphere but that's only in surface area not in depth or volume, well... except relative to common human dimensions. If we could view the Earth as the size of the common schoolroom globe, you know, maybe 18-22 inches in diameter, the atmosphere would be no thicker than the thickness of a dime. No atmosphere on rocky worlds to date has been found that is thick in dimensions, just some in density.

Huge If True?
 

What's with the "if"?

But if anyone wants ice "out of this world", there's no need to go further than the Moon...

So far, there seems to be water most everywhere.


My all-time favorite cosmic find is of course sugar! :D

Water is intriguing of course because animals and plants must have it and also as a source of oxygen and hydrogen. Scaled up, a device called MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment), may open the door to plentiful supplies of O2:
"MOXIE was able to produce 12 grams of oxygen an hour – twice as much as NASA’s original goals for the instrument – at 98% purity or better. On its 16th run, on Aug. 7, the instrument made 9.8 grams of oxygen. MOXIE successfully completed all of its technical requirements and was operated at a variety of conditions throughout a full Mars year, allowing the instrument’s developers to learn a great deal about the technology." https://www.jpl.nasa.gov/news/nasas-...s-mars-mission

Fascinating! The clear evidence of water suggests the likelihood of past life on Mars.

For me the most exciting thing about life on Mars is the thought of finding a single cell, just a bacterium or the Martian equivalent, and studying its chemistry. We would finally find out what bits of living things are really essential and what bits are just accidents of life on earth. For example, would Martian life use DNA/RNA for its internal coding? or something similar but with a different sugar or a different set of bases? or perhaps something completely different. Would Martian proteins be made of the same 20-odd amino acids that we use? I would love to know.

Not Mars, but...

NASA's James Webb Space Telescope has spotted an early yet tantalizing piece of evidence that an exoplanet some 120 light years away could be covered in a massive ocean — that's possibly harboring life.

The telescope detected a molecule called dimethyl sulfide (DMS) — which only living organisms can produce, at least here on Earth — on the planet, which is dubbed K2-18 b.

And...

K2-18 b orbits its host star, a cool dwarf in the Leo constellation some 120 light years away, in the system's habitable zone, meaning that it technically receives enough radiation from the star for liquid water to exist on its surface.

It was first discovered by NASA's K2 mission back in 2015, but only thanks to the James Webb's detailed observations have researchers been able to reveal the presence of these molecules — and the excitement surrounding the discovery is palpable.

More here with great links... https://futurism.com/the-byte/james-...distant-planet

Apparently dimethyl sulphide (CH3-S-CH3) is the compound that gives overcooked cabbage its smell. But I'm always a bit dubious about compounds that on earth are "only made by life". Earth has an oxygenated atmosphere created by life so it's already not a typical planet any more.

Some time ago they found a phosphorus compound in the atmosphere of Venus that on earth is only made by life, and there was feverish speculation for a few days that there could perhaps be some form of airborne life up there; there's obviously none at the surface because it's much too hot. But it all turned out to be a red herring.