Two top scientists believe that there are microorganisms trapped underneath the icy surface of Comet 67P, the comet being probed by the Rosetta spacecraft and its lander module, Philae.

The scientists drew their claims based on the comet's very distinctive features, as shown by the probes. Its "organic-rich black crust" could indicate that there are living organisms below the ice, they wrote in a press release. 

But neither Rosetta nor Philae are equipped with features that can confirm the assumptions by professors Chandra Wickramasinghe and Max Wallis. However, the two reiterated alien life in the comet is possible.

"Five hundred years ago it was a struggle to have people accept that the Earth was not the centre of the universe. After that revolution, our thinking has remained Earth-centered in relation to life and biology. It's deeply ingrained in our scientific culture and it will take a lot of evidence to kick it over," said Wickramasinghe, according to the Guardian.

The two scientists have apparently came up with computer simulations to test their claim with data that suggests, "micro-organisms being involved in the formation of the icy structures, the preponderance of aromatic hydrocarbons, and the very dark surface."

"These are not easily explained in terms of prebiotic chemistry. The dark material is being constantly replenished as it is boiled off by heat from the sun. Something must be doing that at a fairly prolific rate," the scientists further said.

As they presented their case at the Royal Astronomical Society's National Astronomy Meeting in Wales, however, other scientists have reacted to the assumptions.

Rosetta's project head Matt Taylor said that these claims are just "pure speculation," while Monica Grady, who is a chemical analyst looking into Philae's data, said that alien life was "highly unlikely" in the comet, according to the Telegraph.

Another scientist, Jillian Scrudder, who was in the audience when Wickramasinghe and Wallis did their presentation Monday, tweeted that there was "no extraordinary evidence" to the claims.

Finally, Sarah M. Hörst, an expert on complex organic molecules from the Johns Hopkins University said, "The press release basically just says the comet has water and organics."

"We're trying to understand the origins of complex organic materials in the solar system. Where are they created, where are they transported to? What does that mean for the origin of life on Earth, what could it mean for life elsewhere," she added.

"But to say that life must be responsible for the complex organics they are seeing is fundamentally false," she said via io9.