There is a prevailing belief that comets delivered the ingredients for life on Earth. But could they have done the same in other star systems? Scientists investigated this prospect and concluded that indeed, under a crucial condition, it is entirely possible.
The Role of Comets in Sustaining Life
Our existence today, according to some researchers, is thanks to comets. It is hypothesized that these cosmic bodies have delivered the building blocks for life, such as amino acids, to Earth billions of years ago. This remains a hypothesis, yet the discovery of life’s building blocks on comets over the years lends credibility to this theory.
The Comet Bounce Hypothesis
Researchers at the University of Cambridge explored this concept further. If indeed comets brought life’s building blocks to Earth, could they do something similar in other stellar systems, nurturing the genesis of life as we know it? The researchers, in their article published in the Proceedings of the Royal Society A Mathematical Physical and Engineering Sciences, suggest so. However, there’s a catch: the comets must bounce a bit.
Conditions for the Delivery of Life
To deliver life’s building blocks to a planet, comets must collide with it. Yet, the impact needs to be moderated – preferably at speeds lower than 15 kilometers per second. If a comet travels any faster, life’s building blocks would not survive the impact; the resulting force or the high temperatures during the crash would disintegrate them.
Applying the Brakes
To transport these building blocks safely to a planet, the comet’s speed must be decelerated. The researchers discovered that this is most feasible in star systems where planets are relatively closely packed. In such a system, the comet would ‘bounce’ from planet to planet, slowing down incrementally with each encounter. Moreover, every planet has the chance to interact with the comet and capture it, as the researcher Richard Anslow puts it, potentially enabling prebiotic molecules to land on planets.
Understanding the Role of Comets
The researchers stress that they do not seek to assert that impacting comets were essential for life on Earth or the existence of life on other planets as this is far from proven. However, they aim to investigate if comets could have delivered life’s building blocks to planets in other star systems. “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,” says Anslow.
Implications for Future Study
The researchers’ findings could aid the ongoing search for life. On the basis of these, scientists could commence searching for life in star systems where planets are closely packed. Moreover, if life is found in such star systems and not in systems where planets revolve at a significant distance from a dwarf star, this could endorse the idea that comets play a role in the origin of life. “It’s exciting that we can now identify types of systems that we can use to test different scenarios about the origin of life on Earth,” says Anslow.
Conclusion
As we edge close to determining whether the same molecular processes that led to the myriad of life forms around us are at play on other planets, it’s indeed an exciting time, as Anslow remarks. Armed with powerful space telescopes and acquisitions gained over the previous decades in both chemistry and astronomy, we seem to be at a point where we can start answering profound questions about life and its origins.
