Life On Other Planets Essays - Planetary Science, Astrobiology

Life On Other Planets Life On Other Planets Life exists on other planets. Out of the billions of solar systems, there has to be a chance that a least a couple planets have the ability to support life. Life may have developed on the planets like life developed here, but it may have developed differently also. Are they more intelligent than we are or are they single-celled organisms? Do they have broadcast capabilities, so they can contact us? It goes back to how life on Earth started. In the early days of Earth, the atmosphere was just carbon monoxide, but algae developed into plants which produced oxygen (Rather and Bowen 2). That brings us to the question of how the algae got here. The answer to that question may lay right beneath us, at the bottom of the earth. There are scientists in Antarctica digging in the snow hoping to find some answers. Some of earth's fossil records indicate that within a billion year period of it's formation as a planet, as soon as heavy bombardment by asteroids ceased, primitive organisms such as bacteria and algae evolved and spread around the globe very quickly. Those organisms illustrated the totality of life here for the next two billion years or so. Therefore, if life exists on other planets, it might well be in this highly uncommunicative form. Consequently it might be a while until it would finally evolve into a slightly intelligent form of life. As algae became more extensive, they began adding large amounts of oxygen to Earth's atmosphere. The manufacturing of oxygen, fed by energy derived from sunlight, is fundamental to carbon-based life. Oxygen is a chemically reactive gas; without continued replenishment by algae and, later in Earth's evolution, by plants, its concentration would fall. Consequently, the presence of large amounts of oxygen in a planet's atmosphere is a good indicator that some form of carbon-based life may exist there. But there is still a problem as to how the initial jump from non-alive to alive came about. We know a lot of details, and have a pretty good idea of how life got from algae to cat to man, but how we ended up with algae is the big question here. This mystery makes it hard for us to figure out how life would arise on other planets. Life is not all that mysterious, it is a property of a collection of extremely complex molecules (Britt 1). In order to help people figure out what planets out there could support life and may have life on them, we have to look at what life needs to survive. If other planets had carbon-based life they would likely have the same or close to the same chemistry that earth has. Water is an excellent solvent for life's biological reactions and serves as a source of needed hydrogen. Carbon is a particularly suitable building block of life. Carbon is abundant 'in this universe, and no other known element can form the myriad of complex but stable molecules necessary for life as we know it. It is believed that if a planet looks like Earth and has liquid water and oxygen, then this would present strong evidence for its having life. There could be some other non-biological source on a lifeless planet. Life could also develop from some other type of chemistry that does not generate oxygen. We should still be able to detect all stirring from chemical residues. There is a theory that maybe life came from outer space, or the comets and meteorites in it. Like giant interstellar sperm, comets might transport the seeds of life from collapsed space clouds to fledgling and otherwise barren planets, depositing their life-giving substances in a colossal impact (Britt 1). A new computer shows that at least one building block of DNA could develop in space when giant clouds of molecular matter collapse under their own gravity, squeezing and forcing chemical reactions. If the controversial theory gains support, it would be a shot in the arm for an idea more than 20 years old: that life on Earth originated in space (Britt 1). This theory could explain how life got started on our planet so soon after this planet was formed.