When humanity broke the barrier of earth’s gravity and ventured into space, the most glorious purpose we could think of was finding life. At some point, scientists also realised that you do not necessarily need to go on a planet to make a really good guess of whether life exists there or not. As it turns out, the light that is coming from a far planet, even outside our solar system, can tell you about what gases exist in its atmosphere. Now that we know, or at least we think we know, the chemical composition of a faraway planet, how can we make a good guess if life exists there or not, or can we at all?
In a video uploaded by the American Chemical Society on its science communication YouTube channel Reactions, scientist Samantha Jones explains where we are in the path of finding life on other planets.
Jones starts with the question of what life is. According to NASA, life is a chemical system that has two basic features — it is self-sustaining and capable of Darwinian evolution. So how does a self-sustaining chemical system come into existence? Using scientific research, scientists have made a fair guess of how the conditions on earth were when life came into existence. In 1953, chemists Stanley Miller and Harold Urey conducted an experiment in which they tried to replicate those conditions and they were successful in creating Amino acids. Amino acids — structural units of proteins — are the first organic compound which later somehow gave birth to life. Scientists found that the only essential elements for life to originate were Carbon, nitrogen, hydrogen, oxygen, sulfur, and phosphorus. Now scientists know what elements to look for in the atmosphere of other planets.
Nicholas Hud, a scientist at Georgia Institute of Technology, who is working with environments that were possibly present on early earth says in the video, “I feel very confident that human beings will eventually have the knowledge and the tools that will result in the detection of life on another planet in our galaxy.”