Thursday, September 29, 2011

The Earth from Afar


What would our planet look like from afar? Would it look the same if it was closer into the Sun or even if it was orbiting a different type of star?
A team of scientists aim to answer these questions with a model.

A network of scientists brought together by NASA form the Virtual Planetary Laboratory (VPL) and their goal is to use computer simulations to test what a habitable planet looks like over time.
The model integrates a number of factors that cause a planet to be habitable such as; geology, atmospheric parameters and its position relative to other astronomical bodies such as its star.
The task is by no means an easy one as the model will need to reflect the complexity observed of Earths system.

The current count of exoplanets is over 600, most of which are large gaseous worlds. There are, however, a number of Earth like candidates and with missions like NASA's Kepler Telescope which is hunting for exoplanets around solar-like stars or NASA's future planned Terrestrial Planet Finder (TPF) mission; the number of potentially habitable worlds is set to rapidly increase (potentially, being the operative word in that sentence).
This, however, still means that these planets will be viewed as point sources. Where dimensions are inferred and any information about atmospheres concerns the whole planet and not individual regions or clouds.

This is where computer models come in! Observational astronomers will be able to tell you what we can see, be it a signature for water or just an average temperature. Models are then used to determine the possible planetary and atmospheric structure from the data which increasingly requires more complex models with more informational parameters.

The VPL teams model is designed to be a complex model of the Earth as viewed from afar where the atmospheric, and geographical parameters are displayed over the whole planet (in essence it is an extremely pixelated view of the Earth). It also includes a number of changeable astrophysical parameters such as different wavelengths of light, if orbiting a different type of star, and the observation angle, to determine the effect of light off of oceans.
With the collaborative work of a number of teams like this and observations made around the world and from space we may be able to find another Earth.


http://www.ncbi.nlm.nih.gov/pubmed/21631250
The image was taken from the paper written by the VPL team

http://www.ncbi.nlm.nih.gov/pubmed/21631250 .