For the first time ethyl alcohol, the same type found in beverages, and a type of sugar have been found in the alcohol of a comet. According to researchers at the Paris Observatory, the presence of the elements on the Lovejoy comet (formerly C/2014 Q2) supports the theory that the building blocks of life on Earth were deposited by comets.
“We found that comet Lovejoy was releasing as much alcohol as in at least 500 bottles of wine every second during its peak activity,” said Nicolas Biver of the Paris Observatory in a statement.
Biver is the lead author of a paper appearing in Science Advances on October 23.
Scientists think the comets formed out of the same cloud of gas and dust that formed the solar system. It is hoped that by studying the composition of comets, we can learn more about the creation of the sun and planets.
Presently, most comets reside on the outer edges of the solar system, however occasionally a gravitational disturbance will send one into an orbit that brings it closer to the sun. This gives scientists an opportunity to get a look at what they are made of.
As comets approach the sun, their surface warms and surface layers melt. Researchers can then get a look at the chemicals left behind in their vapour trails. The molecules in the comets tail glow at a specific microwave frequency. Special filters on the telescopes allow researchers to study those microwave signatures.
In the early days of the solar systems, comets colliding with one another formed the masses that would become the planets. Long after that period, collisions between planets and comets were much more frequent than they are now. Many scientists think that the compounds which form the basic building blocks of life were deposited by comets, after the early molten Earth had sufficient time to cool.
This discovery lends support to that theory according to Stefanie Milam of NASA’s Goddard Space Flight Center, a co-author of the paper.
“The result definitely promotes the idea the comets carry very complex chemistry,” said Milam. “During the Late Heavy Bombardment about 3.8 billion years ago, when many comets and asteroids were blasting into Earth and we were getting our first oceans, life didn’t have to start with just simple molecules like water, carbon monoxide, and nitrogen. Instead, life had something that was much more sophisticated on a molecular level. We’re finding molecules with multiple carbon atoms. So now you can see where sugars start forming, as well as more complex organics such as amino acids — the building blocks of proteins — or nucleobases, the building blocks of DNA. These can start forming much easier than beginning with molecules with only two or three atoms.”
There is still a good deal of evidence to gather before researchers can have a great deal of confidence in the theory of life-from-comets.
“The next step is to see if the organic material being found in comets came from the primordial cloud that formed the solar system or if it was created later on, inside the protoplanetary disk that surrounded the young sun,” said Dominique Bockelée-Morvan from Paris Observatory, another of the paper’s co-authors.