These are not aliens, but a newly recognized type of bacteria found in the deepest regions of earth.
In class, we divide bacteria into categories depending on their growth and energy requirements. One such division depends on where the bacteria derive their energy. Some bacteria obtain energy from sunlight, and are known as phototrophs (photo: light, troph: obtaining nutrition/energy). Bacteria that utilize organic materials are known as chemotrophs. And we thought that was it…until a recent discovery found bacteria that derive their energy from the radioactivity produced from uranium!
The name of the organism is Desulforudis audaxviator, and it was found in a gold mine. The bacteria harvest molecules that have been energized by being split by radioactivity. The bacteria take in the energized molecules, extract the energy and eject the spent molecule back out. So, would this then make this organism a radiotroph?
The scientists in this article are also hypothesizing that life like this could grow on planets without much of an atmosphere where these bacteria could grow on galactic cosmic rays (GCRs). They used Mars as a possible place for these organisms to exist. Some people are calling these alien organisms, but I like to think of them as an example of just how amazing life on earth can get.
Maybe our next search should be for silicon based life forms that grow on radiation? At this point, I think anything is possible!