Alien Life: Top Bets in our Solar System
Written on Nov 14, 2009 // .Mars
The planet most similar in temperature and size to Earth is Mars. There is evidence of frozen water on its polar caps and geological features indicate there may have once been flowing water. It does not have much atmosphere, so whatever life there may be would most likely be found underground, shielded from lethal radiation that exists at ground level.
A four and a half billion year old meteorite provides more evidence of life on Mars. The rock, found in Antarctica is believed to be the result of a large asteroid impact on Mars that dislodged it and sent it into orbit around the sun. It eventually fell out of orbit some 13k years ago and landed in Antarctica. A high resolution image reveals ovoid shapes that could be fossil signs of bacteria.
Other evidence of life on Mars is regular plumes of methane being released into the Martian atmosphere. This may indicate biological activity beneath the ground.
Finally, Hungarian scientists believe that seasonal appearance of “gray fuzzy spots” on Mars may indicate life. The spots grow during the Martian spring, shrink during the colder periods and reappear in a similar configuration the next year. Others however, believe that these seasonal spots may be the result of huge geysers spewing particles into the atmosphere.
Future missions to Mars plan to drill down into the planet and bring back samples.
Enceladus
Of Saturn’s wide array of moons, the sixth-largest, Enceladus, is the most likely candidate for alien life.
The flyby of Cassini probe indicated its surface is almost entirely made of ice, with a good chance of liquid water below the surface. There was evidence of basic organic molecules that make up life.
The core of Enceladus appears to be molten rock which would result in temperatures below the surface that would be ideal for life as we know it.
Enceladus regularly spews plumes of liquid water. An analysis of these plumes indicated that it was salt water, i.e., similar to where life began on Earth.
Europa & Io
Galileo discovered four of Jupiter’s moons in 1610: Callisto, Ganymede, Io and Europa. The latter two are good candidates for alien life forms. Europa has a frozen surface, but probably has liquid water below its surface. Volcanic activity would provide heat and a chemical environment similar to that of Earth’s hydrothermal vents, where giant tube worms, shrimp, and clams thrive.
Io is one of the few moons that has an atmosphere. Its volcanic activity makes it warmer and it has complex chemicals necessary for life.
