The iconic comet upon which the spacecraft Philae dramatically landed last year, 67P/C-G, has been host to a wealth of surprises for astronomers on Earth. Its unusual shape, its varying mineral composition, and the crumbling craters over its surface, which imply the existence of ice water, to name a few. But more recently, there have been buzzworthy claims that there could be microbial life on the comet.
There are two main reasons for this sensational assertion. Firstly, the comet has some regions of organic-rich, coal-black crust. One possible explanation for this substance could be the presence of microorganisms below the icy surface of the comet. The second reason is that the spacecraft orbiting the comet, Rosetta, could have picked up particles from the comet that resemble viral particles. Both of these justifications could point to life on the comet. However, there are a lot of other much more likely explanations.
For microbes to be responsible for the dark material found on the comet, they would need to be able to survive in some extremely harsh conditions. All of the water on the comet is solid ice or vapor, and the average surface temperature is –70oC (–94oF). It would take some very hardy microbes to survive on this freezing space rock.
Vexingly, Philae actually has no way of directly detecting the presence of life on the comet. When Philae was being built, it was considered unlikely that life would ever exist on the comet. As a result, no equipment was included to detect the symptoms of life.
There are plenty of scientists who are skeptical about the presence of alien microbes on the comet. Rosetta researcher Dennis Bodewits, from the University of Maryland, told IFLScience that there was no chance that life could be found on the comet. However, he noted that that building blocks for life may be present on the comet.
"Comets do have complex molecules, and it's been suggested that comets may have either brought water or complex molecules to Earth.
"Also, in the cloud of gas around it you have a lot of interesting chemistry going on." This could explain the presence of virus-like particles detected by Rosetta in the dust around the comet.
So, there's no hard evidence of living microbes on the comet, and what's more, Philae's equipment is incapable of confirming any tenuous signs of such life anyway. The possibility of life on the comet will be presented and discussed at the Royal Astronomical Society's National Astronomy Meeting this week. There can be no conclusive evidence anytime soon, so until then scientists can only speculate.
[H/T: The Guardian]