“Comets are loaded with all the raw materials like water, CO2, methane, ammonia, needed to assemble more complex organic molecules, perhaps sparked by UV-photons from the Sun or cosmic rays, or in the shock that occurs when a comet hits the surface of a planet like the young Earth”, said Mark McCaughrean, a senior scientific adviser at the European Space Agency. The depth and shape of the holes Philae’s legs left at the site of the first bounce, for example, along with the force measured by the lander, let scientists calculate that the surface was granular, but more solid a foot or two down.
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Philae’s on-again, off-again relationship with its scientists back on Earth has proved a soap drama in its storyline, with an explosive start seeing its whizz out of Rosetta and down onto 67P/Churyumov-Gerasimenko.
It took a couple of jerks to land on the comet. As Philae approached 67P, far-field sequence and the near-field sequence images revealed a clearer picture of the comet’s geography; an analysis of Rosetta Lander Imaging System (ROLIS) descent images by Stefano Mottola et al. suggests that 67P’s landscape is shaped by erosion.
The Rosetta orbiter is still periodically listening for signals from Philae, but it’s appearing less likely that the lander will be able to collect the extended amounts of data originally planned. In one of those papers, a team of scientists led by Jens Biele of the German Aerospace Center (DLR) detailed the events shortly after Philae’s harrowing landing.
Philae’s final resting place, by contrast, has a surface more like asphalt in texture.
What’s more, the scenic route Philae took lead to a vast array of images from parts of the comet we otherwise would have missed. The drilling mission failed.
The authors conclude that the complexity of the comet’s chemical makeup, and the presence of organics containing nitrogen, “imply that early solar system chemistry fosters the formation of prebiotic material in noticeable concentrations”.
When Philae landed, it bounced off of the intended landing surface – which was soft – and onto the edge of a crater, where the surface was significantly harder.
They detected 16 organic compounds, four of which – methyl isocyanate, acetone, propionaldehyde and acetamide – were previously unknown to exist on comets.
A rain of comets may have brought life’s building blocks to Earth, kickstarting the process that eventually led to humans smart enough to visit a comet.
They now believe the comet has a thin, crusty layer beneath its dusty surface. It’s because nobody has ever taken a chemical sample from a comet before.
The MUPUS thermal sensor, on Philae’s balcony, revealed a variation in the local temperature between about -180ºC and -145ºC in sync with the comet’s 12.4 hour day.
Around 85 percent of the comet’s interior is empty, according to the electromagnetic data, indicating that the comet is incredibly porous.
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They were thrilled, therefore, when the lander abruptly woke up and phoned home in June, presumably thanks to changes in the comet’s orientation that allowed the solar panels to work after seven months in darkness. But at the time, no one was sure if this was actually a big deal or not, since these molecules might have just been from simple gases like methane (which wouldn’t be very unexpected). These molecules, Bibring said, formed in the cold of space, possibly even before the grains clumped together to become the comet.
