Comet Hartley 2 contains water?

Water is everywhere.

Not too long ago, astronomers were surprised to find water elsewhere. Now, it seems that whenever we search for water... there it is. The stuff is everywhere. Even on Mercury (underground, near the poles).

Water was already present in the gas and dust nebula that collapsed to form our solar system. Beyond a certain distance from the proto-sun, beyond what we now call the "frost line", the molecules were cold enough to form ice crystals. These acted just like Velcro, explaining why the planets that formed beyond the frost line became so big (the gas giants).

When the Sun finally turned on, all the remaining water (and other volatiles) were pushed back to the Kuyper belt and the Oort cloud, where the comets were formed.

So now, we would be surprised if a comet did NOT have water.

Yes comets are mostly frozen water and carbon dioxide. Something with so little mass? A cup will hold water, it has much less mass than a comet.

there is water on Mars, besides the shown fact that it is not liquid. there is evidence of ice in Mars' polar areas, kinda like on earth. i will't remember for useful yet i think of it would desire to be underground. there is likewise evidence that Mars used to have liquid water (there are what seems lots like dendritic drainage varieties). as a ways because of the fact the moon, any water on the products that hit it gets vaporized in the time of the end result. i stumble on it very a ways fetched to have self assurance that the water on earth have been given right here from comets and such. there's a great style of water interior the oceans... i might somewhat ought to droop my disbelief to think of any important volume got here from area and survived being vaporized interior the end result. perhaps something else rode down on a comet and started out a chain reaction that created the water... something alongside those traces sounds lots greater reasonable.

Because the temperature is so cold - below freezing.^

Because it's cold. very cold.