Question: is there water in space?

Kevin Motherway answered on 12 Nov 2014:

Yes there’s lots of water in space particularly in comets and in fact that’s what delivered most of the water we have on earth (as it does to any modest sized planet) its just that we are just the right distance from the sun to have liquid water and the planet is big enough and has enough gravity to hold onto its the water in its atmosphere too. We have categorically found water ice on mars and you may get liquid water in deep valley gorges where the pressure from the thin Martian atmosphere is high enough to allow liquid water to exist.

Most water on Mars behaves like CO2 ice on earth which is also known as “dry ice” because it melts or sublimates straight to gas (without leaving a puddle of CO2 liquid hence the name “dry”). So water on Mars exists as a solid ice and vapour that falls as snow but its rarely present as liquid water. Where pressure is high enough it can be present as water so inside in rock formations where the pressure is higher we probably get liquid water.

Europa one of the moons of Jupiter is completely covered in water ice, with lots of cracks on the surface hinting it may have liquid water beneath.

Enceladus a moon of Saturn actually has water volcano that feeds the outer ring of Saturn and keeps it topped up with material!