An artist's impression of Rosetta's lander Philae (front view) on the surface of comet 67P/Churyumov-Gerasimenko by the European Space Agency on December 20, 2013. (AFP PHOTO / ESA MEDIALAB)
The comet landed on by the European spacecraft Philae could be teeming with alien microbial life, according to two leading UK astronomers.
Scientists say the features of the comet, named 67P/Churyumov-Gerasimenko, such as its organic-rich black crust, are most likely explained by the presence of living organisms beneath an icy surface.
European Space Agency's Rosetta spacecraft, which is orbiting the comet, is also said to have picked up strange clusters of organic material that resemble viral particles, Guardian reported.
Astrobiologist Chandra Wickramasinghe and colleague Dr Max Wallis, from the University of Cardiff in UK, believe 67P and other comets like it could provide homes for living microbes similar to the "extremophiles" that inhabit the most inhospitable regions of the Earth.
They have carried out computer simulations that suggest microbes could inhabit watery regions of the comet.
Their findings show that organisms containing anti-freeze salts could be active at temperatures as low as minus 40 degrees Celsius.
The comet has a black hydrocarbon crust overlaying ice, smooth icy "seas" and flat-bottomed craters containing lakes of re-frozen water overlain with organic debris, researchers said.
Data from the comet points to "micro-organisms being involved in the formation of the icy structures, the preponderance of aromatic hydrocarbons, and the very dark surface," said Wickramasinghe.