We’ve all heard it before, a planet found orbiting another star, several light years from Earth that has the potential to harbor life. Later it is realized that these planets are made entirely of gas, orbits too close or too far from its star or other things that eliminate the claim for life as we know it.
Recently, however, scientists have claimed that a planet orbiting Gliese 581, a red dwarf star located about 20 light years from Earth, is the first true “Goldilocks” planet. The new planet, called Gliese 581g is just the right size and distance from its star to have liquid water on the surface. This, along with other things such as being a rocky planet, having an atmosphere and temperate regions is what makes scientists so excited about the possibility of life. The planet is about three times the size of Earth and is tidally locked to its star, meaning that one side is in perpetual daylight. The other side never faces the star and is in permanent darkness. This means that, if life exists on Gliese581g, it is likely going to be in the line between shadow and light, an area known as the “Terminator.”
The planet was first discovered in 2007 and was then said to be too far away from its star to harbor life. Recent calculations, however, put the planet just inside the habitable zone of the cool star. It orbits the red dwarf once every 66 days. Because planets so far away cannot be seen directly, scientists look for a wobble in the star which indicates that other bodies are effecting it with their gravity. By measuring the wobble’s strength and duration, the size and likely weight of the planet can be determined. Using spectrograph telescopes, composition and atmosphere can be determined. Some scientists speculate that if there is indeed life in the universe beyond Earth, we will know in the next 15 – 20 years.
I, for one, believe that life on other worlds is not only present, but plentiful in the universe. While intelligent life may be relatively rare, small organisms and other creatures are surely alive on planets around other stars. While I understand why we first look for life as we know it, that is, life that requires water, atmosphere and light, I believe there is also life out there that needs something totally different. Maybe some life lives from the sulfuric acid in the atmosphere or makes its food from liquid nitrogen present on some worlds.