Tuesday, 29 May 2012
OK so I have been hearing and reading a lot about Earthshine this week. http://www.newscientist.com/article/mg21328546.000-earthshine-holds-clues-to-exoplanet-aliens.html
Easthshine is basically the light reflected off the Moon from the Earth. http://science.nasa.gov/science-news/science-at-nasa/2002/12apr_earthshine/ .
Current research is using Earthshine to determine the atmosphere of the Earth. The idea is that light interacts with the chemicals in the atmosphere and this causes the light to be interpreted differently. By looking at the light reflected back from the Moon we can view the light as if it was from an exoplanet - for example Kepler 22b.
This in short means that by looking at the light spectra we get from Earthshine we can use this as a benchmark for the spectra we'd expect from a planet with life. Or at least the composition of the atmosphere of a planet with life. The thinking is that the Earth has life, so if we know what the atmosphere of the Earth looks like from the spectra - the % amount of carbon dioxide, oxygen etc - then we can compare this to planets in different galaxies. If these planets have similar compositions then that increases the chance of those planets being able to support life.
Whether it means we are closer to finding life out there or not I do not know. However it does mean that we will be able to narrow down our search a bit.
Which when you are searching in the infinite Universe is a good way to start!