Oasis on the Sun

With a surface temperature of 10,000 degrees Fahrenheit, the sun is the last place you’d expect to find water. But this past May researchers announced they’d found a solar oasis: a sunspot that during its brief existence contained enough water--albeit in scattered molecules--to fill a small lake. Chemist Peter Bernath and his colleagues at the University of Waterloo in Canada studied this 1991 sunspot, which at 5500 degrees was one of the coolest ever recorded--cooler, in fact, than the temperature at which H2O is completely dissociated into H and OH. (Sunspots are relatively cool because their intense magnetic fields keep a lid on the heat rising from inside the sun.) To see if water molecules had formed in the spot, Bernath examined its spectrum. And to know what to look for--water molecules absorb and emit different wavelengths of light when they’re superhot and furiously jiggling--Bernath heated a tube of water in his lab to 2800 degrees. You’d want to get the same temperature as the sunspot, he says, but our tube cracked and our furnace wasn’t going to get much hotter. Nevertheless, the lab and sunspot spectra were similar enough to reveal a thin smattering of water molecules in the 12,000-mile-wide sunspot. In liquid form the water would have filled a lake four square miles in area and 300 feet deep.