Science fiction novels and movies have been depicting asteroids as harbinger of death and destruction and that’s primary because these celestial bodies have been linked with destruction and mass annihilation of species through previous studies.
However, at least one scientist believes that these asteroids could serve as time capsules that could reveal to us how life started on Earth. Nicholas Hud is the Director of the NSF-NASA Center for Chemical Evolution at the Georgia Institute of Technology and he says that finding molecules in asteroids provides the strongest evidence that such compounds were present on the Earth before life formed.
If we find out what molecules were present before life was present on Earth, we would then be able to find out what led to the formation of amino acids and related compounds that, in turn, came together to form peptides, small protein-like molecules that may have kicked off life on this planet.
Study of compounds present in asteroids and meteorites isn’t a new field. NASA scientists have been at it for decades and over the years have gained solid understanding for what might have been present when the Earth itself was formed. One such experiment was the Miller-Urey experiment carried out in 1952. Through this experiment scientists tried to simulate conditions believed to have existed on the early Earth and ended up producing more than 20 different amino acids, organic compounds that are the building blocks for peptides.
The experiment was kicked off by sparks inside a flask containing water, methane, ammonia and hydrogen, all materials believed to have existed in the atmosphere when the Earth was very young. From that experiment till now, scientists have garnered immense knowledge of conditions on Earth that may have existed before life spawned on Earth.
Hud believes there are many possible ways that the molecules of life could have formed. Life could have gotten started with molecules that are less sophisticated and less efficient than what we see today. Like life itself, these molecules could have evolved over time.
Geologists believe the Earth was very different billions of years ago. Instead of continents, there were islands protruding from the oceans. Even the sun was different, producing less light but more cosmic rays – which could have helped power the protein-forming chemical reactions.
Rather than a single spark of life, the molecules could have evolved slowly over time in gradual progression that may have taken place at different rates in different locations, perhaps simultaneously. Different components of cells, for example, may have developed separately where conditions favored them before they ultimately came together.
Knowing what conditions were like on the early Earth therefore gives scientists a stronger foundation for hypothesizing what could have taken place, and could offer hints to other pathways that may not have been considered yet.