Water is the most abundant solid material in space. Astronomers see it on various planets, on moons, in comets and in interstellar clouds. But how did it get there? Nobody really knows how water could possibly form in the freezing darkness of interstellar space.

At least they didn’t until now. Today, Akira Kouchi and buddies at the Institute of Low Temperature Science at Hokkaido University in Japan say that have created water for the first in conditions similar to those found in interstellar space.

Water forms quite easily when oxygen and atomic hydrogen meet. The problem is that there is not enough of it floating around as gas in interstellar dust clouds. So instead, the thinking is that water must form when atomic hydrogen interacts with frozen solid oxygen on the surface of dust grains in these clouds.

Kouchi and co recreated this process by creating a layer of solid oxygen on an aluminum substrate at 10K and then bombarding it with hydrogen. Sure enough, infrared spectroscopy confirmed the presence of water and hydrogen peroxide, and in the right quantities to explain the abundance of water seen in interstellar clouds.

That’s cool and in more ways than one. All the water in the solar system–in comets, on Mars and in the oceans on Earth–must have formed in exactly this way in the interstellar dustcloud which pre-dated Sol and the planets.

So that’s not just any old water you’re sipping, that’s interstellar star juice.

Ref: arxiv.org/abs/0805.0055: Formation of Hydrogen Peroxide and Water from the Reaction of Cold Hydrogen Atoms with Solid Oxygen at 10 K