Stardust sounds magical enough as it is. But now scientists have observed for the first time that it contains water — which, in turn, could suggest that life is universal.
The water forms within dust grains when they're bombarded with charged winds from the sun. The chemical reaction set up by the winds was hypothesised by scientists in the past, but this is the first time anyone's actually found H2O trapped inside real stardust.
The finding saw John Bradley, from the Lawrence Livermore National Laboratory in California, take a very close look indeed at the outer layers of interplanetary dust particles that were found in the Earth's stratosphere. Incredibly high-resolution microscopy revealed tiny pockets of water in the already-tiny specks of dust — each of which themselves measured less than 25 micrometres, half the width of a human hair. New Scientist explains how the water forms:
The dust is mostly made of silicates, which contains oxygen. As it travels through space, it encounters the solar wind. This stream of charged particles including high-energy hydrogen ions is ejected from the sun's atmosphere. When the two collide, hydrogen and oxygen combine to make water.
Roll the new finding together with the fact that there are plenty of organic compounds in interplanetary dust, and the suggestion is, as New Scientist points out, that stardust contains all the basic ingredients needed for life like that on our planet. Because it's believed that similar stardust grains exists in solar systems throughout the universe, the finding bodes well for the existence of life elsewhere. In other words, we're almost certainly not alone. [PNAS via New Scientist]