Panspermia, or the idea that life could be spread between planets throughout the galaxy by travelling through space, has been generally discounted in the serious scientific community for a long time.  The reason for this is this is that it has been generally believed that no organism could survive the harsh environment of space.

Recent experiments by the European Space Agency might have recently forced a rethink on this belief however.

http://www.esa.int/esaCP/SEM72XRJR4G_index_0.html

Not only can some lichens survive long exposures to the vacuum of space, but also some simple animals and plants can too.  The key appears to be that the organism must have a low water content.  In addition to these findings experiments are currently underway to look at the survivability of micro-organisms in space like environments, although the experiments are currently being conducted on Earth.

Now don’t let these findings disturb you too much and make you start reaching for your copy of “Day of the Triffids” or “War of the Worlds”.  The current problem preventing general acceptance of the Panspermia theory is the extreme heat generated by the friction of re-entry through atmosphere.  No organism has yet been found that can survive that – although experiments to investigate this are due next year.

There just has to be some good SF stories in this…