Philae Proves There’s More to Comets Than Dust and Ice

The idea that comets are just dusty cosmic snowballs may finally be laid to rest with new findings from the European Space Agency's Philae robot. When the lander crashed onto comet 67P last November, it ended up getting a good look at the surface, as Mike Lemonick reports for National Geographic — uncovering information about the comet's innards and even finding organic material.

Here's how the crash landing went down: Philae hit the surface about a half a mile up from its target, nicked a crater, did a flip, bounced again and landed on its side in a ditch. Though the bounces were hardly planned, they allowed the robot to collect data from two different areas of the comet, writes Chris Crocket for Science News. For 60 hours, Philae busily collected data before it lost power and went to sleep. Researchers have analyzed the data and their results appear in this week’s Science.

Radar scans revealed that ice and dust evenly comprise the comet’s innards, writes Crockett. The lander snapped images of 67P’s surface, which ranges from grainy sand to a more asphalt-like material and is strongly shaped by erosion.

Coincidentally, the robot kicked up dust when it landed, allowing researchers to analyze compounds in the dust using the robot’s mass spectrometer, explains Lemonick. The sample turned up evidence of 16 organic compounds in dust on the comet’s surface, four of which have never been detected from far-off telescopes. The presence of organic material, an essential part of life, points to the theory that comet impacts jumpstarted life here on Earth.

And that's just the beginning for Philae, which awoke on July 14 and began powering back up. ESA scientists hope to use the robot to drill into the surface of 67P — perhaps revealing new secrets about the inner lives of comets. Regardless of what the next phase of Philae's observations reveal, it’s clear that comets are hardly the loosely packed, rocky snowballs that scientists suspected them to be.

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Helen Thompson writes about science and culture for Smithsonian. She's previously written for NPR, National Geographic News, Nature and others.