Philae's Comet could possibly be covered in primitive alien life, according to a pair of astronomers studying data from the icy body. The theory was announced July 6.
The Rosetta spacecraft, which launched to the comet from Earth in 2004, has recorded strange readings from the surface of the icy body, which could be consistent with life. Black crusts are seen over ice lakes on the comet, along with peculiar boulders and craters with smooth bottoms. Boulders appear to have moved over the surface of the comet, and cracks seem to have filled in over time. Each of these features could be explained by the presence of an alien form of microscopic life, these researchers are claiming.
Comet 67/P is racing toward the sun at a velocity of over 20 miles per second, but sublimation (material turning directly from solid into gas) was seen before temperatures should have been hot enough to drive the change. Gas ejections were seen taking place on the comet, mainly from sinkholes and basins. Microscopic life could be driving this process through the formation of high-pressure pockets of gas beneath the cometary surface. This could break apart the material above the deposits, driving material into space.
As the comet approaches the sun, heating could cause the ice trapped in cracks to melt. This could, theoretically, allow any microscopic beings to colonize the slush, where the lifeforms would be trapped once the comet heads once again into the depths of space.
"Organisms containing anti-freeze salts are particularly good at adapting to these conditions and some could be active at temperatures as low as minus 40 degrees Celsius (minus 40 degrees Fahrenheit)," Max Wallis of the University of Cardiff and Chandra Wickramasinghe of the Buckingham Center for Astrobiology stated.
The comet reached this temperature in September 2014, when the icy body was still 310 million miles away from the sun. At that time, astronomers were already starting to see gas sublimating from the surface of the body.
Conditions for life on Comet 67/P could, in fact, be better than those seen in some regions of the Earth, the pair of researchers speculate.
"Rosetta has already shown that the comet is not to be seen as a deep-frozen inactive body, but supports geological processes and could be more hospitable to micro-life than our Arctic and Antarctic regions," the pair reports.
Sublimation of material from comets drives material into space, which is later pushed backwards by pressure from the sun. This is what drives the distinctive tails for which comets are best known.
Comet 67/P, along with Rosetta and Philae, will make their closest approach to the sun on Aug. 13.
The idea of how alien life could explain unusual features of Comet 67/P was presented to a meeting of the Royal Astronomical Society (RAS), held in Wales on July 6.