How did life on Earth start? And could something similar happen on another planet (or moon)? It is not an easy question, nor is it one we have a satisfactory answer to – yet. A Rutgers University-led team of scientists called ENIGMA have been given an (approximately) $6 million grant by NASA to investigate the matter further over the next five years.
There is one hypothesis that comes down to something called a "protein nanomachine". These are specific enzymes formed by interactions between amino acids, which play a role in many crucial biological processes, even using the oxygen we breathe to power our cells – a process we can all agree is crucial to life. Before you go all Scientologist and picture little alien spaceships bringing these life-forming compounds to Earth, these protein nanomachines were not planted by some advanced exo-civilization but delivered naturally by meteorite.
Paul G Falkowski is the principal investigator of the project and a professor at Rutgers University, New Brunswick. In an interview with Rutgers Today, he explained exactly what it is ENIGMA (Evolution of Nanomachines in Geospheres and Microbial Ancestors) is trying to achieve.
"Life literally is electric," said Falkowski. "We breathe in oxygen and breathe out water vapor and carbon dioxide, and in that process we transfer hydrogen atoms, which contain a proton and an electron, to oxygen to make water (H20). We move electrons from the food we eat to the oxygen in the air to derive energy. Every organism on Earth moves electrons to generate energy."
Therefore, life itself relies on this movement of electrons. Scientists don't yet know how these processes first evolved. What they do know, explained Falkowski, is that in the planet's very early history, amino acids traveled to Earth on meteorites. The ENIGMA team suspect that some of these combined to form nanomachines before life began.
"Each time we take a breath, an enzyme [a nanomachine] in every cell allows you to transfer electrons to oxygen," he added. "Enzymes, like all proteins, are made up of amino acids, of which there are 20 that are used in life."
Now, they are attempting to recreate the process with the tens of thousands of protein structures held in Rutgers' Protein Data Bank.
If proven correct, this would explain not just how life developed here on Earth but how it has in the past, does in the present, or could in the future on other planets. In the last decade, astronomers have discovered more than 3,700 planets outside our Solar System, some of which could – potentially – harbor life.
"Many of these are potentially rocky planets that are close enough to their star that they may have liquid water, and we want to try and understand if the gases on those planets are created by life, such as the oxygen on Earth," Falkowski explained.
However, he thinks it is unlikely we will find evidence to prove the existence of life on Mars anytime soon.