HOW DOES THE SUN'S CORONA, at a temperature of millions of K, draw energy from the sun, whose surface is a much cooler 6000 K? New measurements by the SOHO satellite reveal the presence of tens of thousands of magnetic dipoles at work in the sun's surface layer. The SOHO researchers surmise that the magnetic-field loops rising up from the surface are so dense that they clash, creating "short circuits" in which powerful electrical currents can flow, delivering energy to the corona above. (Science News, 8 November.)