Water from space ?

[Getragdogleg]

I recall reading somewhere an idea that water arrives on Earth from space, presumably vii lumps of ice/meteorites/comet remains.

Is this rubbish or is there a bit of truth that water does indeed come here from space ?

[Getragdogleg]

I am sat here now wondering how much water (and other stuff) arrives here from space each year, is it measurable ?

I bet if it is it is one of those surprising figures that is larger than you think.

[Getragdogleg]

With regard to the Helium, Presumably the US have stocks because they condensed it down and stored it in the first place.

It's not a case of the US having all the Helium in the world and when it is gone it is gone, it's more a case of the US having stock that is cheap and when it's gone then everyone else must condense it so it becomes an expensive gas again.

[Getragdogleg]

Right, I see, but where did the US get it from and why ?