Credit: SOHO (ESA & NASA)
No sooner had smoke from Independence Day fireworks cleared last summer than sun-watching satellites spotted some pyrotechnics of their own. On 6 July 2011, a soccer-field-size comet plunged into the searing solar atmosphere (main image), broke into a dozen or so pieces, and then evaporated over the course of 20 minutes. Solar and Heliospheric Observatory, a joint mission of NASA and the European Space Agency, has observed more than 2100 such sun-grazing comets, and scientists have inferred the scorching deaths of those that didn't emerge from behind the disk that blocks direct sunlight from blinding the probe's sensors. But the comet that disappeared last summer suffered its death throes in full view of NASA's Solar Dynamics Observatory (SDO), which typically can't discern the dim glow of comets against the bright background of the sun's face. By stringing together SDO images, however, which are taken once every 12 seconds, scientists for the first time directly witnessed the death of a comet as it unfolded. (You can watch the blink-and-you'll-miss-it video here.) In today's issue of Science, the researchers estimate that the ultra-bright comet, which probably weighed about as much as an aircraft carrier, blazed to within 62,000 miles of the sun's surface before evaporating.
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