Planets around distant stars, and the search for life on them
The laws of physics and mathematics are valid in space as well as on the Earth. But what about biology? Do there exist any general “laws” of biology? Do the properties of carbon atoms inevitably lead to organic and biological processes? And if life exists somewhere else, does its evolution follow similar patterns as on Earth?
In recent decades, many planets have been found around stars other than our Sun, and some of them appear similar to Earth. The closest among these exoplanets can be observed well enough to search for biological markers, chemical substances in their atmospheres, which could indicate the presence of life. In the current terrestrial atmosphere, both oxygen and methane are present, indicating that something maintains their balance, without which methane would have burnt out long ago. Using large telescopes, traces of such and other molecules are searched for in the spectra of exoplanets, trying to deduce about possible biological processes many light years away.
Dainis Dravins (Lund Observatory, Sweden)