Astronomers are changing their tune and now think extraterrestrial life may be able to survive on more planets than they originally thought. In fact, there may be seven times more life bearing planets than they originally estimate.
Earth differs from most planets in that it orbits the Sun on a fairly circular orbit. Most other planets orbit their suns on much more elliptical paths. On those planets, the temperature and climate will vary widely as the planet dips into, and out of, the habitable zone now and again. Up until now, scientists have felt this would prohibit the formation of life on planets with such wide-ranging environmental conditions. However, now they are changing their tune.
Stephen Kane, of NASA’s Exoplanet Science Institute, explained:
Some organisms can basically drop their metabolism to zero to survive very long-lasting, cold conditions. We know that others can withstand very extreme heat conditions if they have a protective layer of rock or water. There have even been studies performed on Earth-based spores, bacteria and lichens, which show they can survive in both harsh environments on Earth and the extreme conditions of space.
Kane also pointed out that planets may not be the only harbinger of life. Moons and other orbiting bodies such as comets could also harbor life.
