Quote:
Originally Posted by renormalised
The problem with detecting water on any giant planet is its density. It's a lot denser than the normal atmospheric constituents, even when they're in their liquid forms or solid forms. So, it gradually sinks down into their atmospheres to the bodies of these worlds. You will have some in the lower atmospheres though. But it's usually too deep to detect spectroscopically. That's why, when Galileo sent its atmospheric probe into Jupiter, they found a relatively dry atmosphere (at least in that area where it went in). In any case, the probe never got low enough down in the atmosphere to get to the water layers. It was crushed beforehand by the pressure.
But they can tell it's present through lightning. Water is a polar molecule, so it can carry a charge. You need water molecules/ice to create the charge separation in clouds to generate lightning.
|
So other molecules could also create the charge separation ?
Mars is another one. I've tried to find hard evidence of 'big' H2O on the Northern pole, everywhere. Mostly they say 'is believed to exist'. However, recent orbiting surveys have detected 'trace' amounts of H2O in the atmosphere above the pole. However from the same measurements, they also say that it is 'mostly' frozen CO2.
More evidence they commonly cite for Mars is geological features that resemble features on Earth where we know H2O has flown. However, can they differentiate what happens when massive amounts of CO2 sublimates and flows through soil like that on Mars, from H2O doing the same ?
If so, how do they do these tests, here on Earth ?
(I'm probably on my own on this one I guess I'll continue my search, quietly).
Cheers