In Search For Extra-Terrestrial Life, Scientists Find A Clue For Building Blocks

Scientists looking for how life started on Earth have said comets may have played a major role in it. They also said that celestial objects are doing the same on other planets. In a research published in Proceedings of the Royal Society, scientists have explained how comets delivered organic material, necessary for life to start, to exoplanets. For a planet to sustain life, it must have organic material built from the elements like carbon, hydrogen, nitrogen, oxygen, phosphorus and sulphur.

Researchers from University of Cambridge said comets travelling at slow speed delivered these materials to planets outside our solar system. High speed would destroy these essential molecules, they said in the study.

"We're learning more about the atmospheres of exoplanets all the time, so we wanted to see if there are planets where complex molecules could also be delivered by comets," one of the authors of the study, Richard Anslow, from the Institute of Astronomy at Cambridge University in the UK, said in a release detailing the findings.

"It's possible that the molecules that led to life on Earth came from comets, so the same could be true for planets elsewhere in the galaxy," he added.

But how did scientists arrive at this conclusion? According to the study, they used mathematical modelling techniques to analyse the likelihood of such a scenario taking place.

The researchers deduced that for such a thing to happen for a planet the size of our Sun, the planet needs to be low mass and it is helpful for the planet to be in close orbit to others in the system.

In such a scenario, a comet could be pulled in by the gravitational pull of one planet, then passed to another planet before impact. If this 'comet-passing' happened enough times, the celestial object would slow down enough so that some prebiotic molecules could survive atmospheric entry.

Prebiotic molecules contain the chemical elements needed for life.

The scientists also said that these findings could eventually help scientists in their search for extra-terrestrial life. Though such a discovery is yet to happen, each new find on the possibility of life-giving molecules leads them a step closer.