IT’S official鈥攕unspots are damp. Physicists in Britain say their
computer calculations leave no doubt that the Sun’s dark patches contain
water鈥攁s much as 10 per cent by weight.
By comparing the spectrum of light emitted by sunspots with that of steam in
the laboratory, researchers first guessed two years ago that sunspots might
contain steam. But the results were inconclusive. In the lab, they were only
able to heat steam to about 1500 掳颁. Sunspots are much hotter, at about 3000
掳颁.
Oleg Polyansky and Jonathan Tennyson of University College London and their
colleagues say in last week’s Science (vol 277, p 346) that they have
used computers to work out what the infrared spectrum of a watery sunspot at
3000 掳C should look like. Comparing it with the real thing, they found an
almost perfect match. “This evidence is absolutely secure,” says Tennyson.
