If comets are, largely, water (ice) why is this water coalescing in space?

Question

Where does all this water originate?

Answer 1

Both hydrogen and oxygen are very abundant atoms in space.

Any environment where there is enough dust to absorb a lot of the UV and higher energy photons, you should get a lot of gaseous water, because there are lots of the constituents and no high energy phtons to destroy the molecules. Once you have vapor phase water, youjust need it to get cool enough to condense. Water vapor is seen in the circumstellar shels of many red giant stars; and water ice is seen in the one with lots of dust.

Its not at all surprising that water ice condenses.

In the case of the solar system - there would have been lots of water vapor which could condense into ice far from the sun - which is why we seen water ice in comets and on moons beyond the asteroid belt.

Answer 2

At low pressures, water can only have two phases: Solid and vapor. When it cools down, it becomes solid, when heated it becomes vapor.

As space is actually a pretty cold place, water is usually in it's solid form, unless the sun shines on it and heats it.

Water is one of the more stable molecules, because it has a very low energy state. This means, radiation also needs a lot of energy to split it again into hydrogen and oxygen, while other molecules are more sensible. Also, many chemical reactions result in water being formed, because of it's lower energy state.

Answer 3

This is just me thinking, but I feel like most comets have pieces of rock or whatever in the middle, and as they fly through space, ice gravitates to them as they get close to ice rings of planets or just random ice in space. I mean, the comet had to originate somewhere, and it wasn't always going as fast as it was, so maybe while it was moving slowly it attracted these random bits of ice to it. Really interesting question though, thanks for making me think!

Answer 4

That's a good question. I'm giving you a star so I can read what others say, I hope someone knows.  Take Care.

Answer 5

well comets are some pieces of planets tat have been destroyed for some unknown reason so the comet may have come from a planet that had water on it