whatsamatter guys? it's not so improbable. I think it is an accepted possibility that life on earth was originally seeded from space..
if it could have happened 3 or 4 billion years ago, why not tonight, or last year?
from:
http://www.sciencemag.org/cgi/content/full/309/5731/89
"...other scientists have focused their efforts on figuring out how the lifeless chemistry of a prebiotic Earth could have given rise to an RNA world. In 1953, working at the University of Chicago, Stanley Miller and Harold Urey demonstrated that experiments could shed light on this question. They ran an electric current through a mix of ammonia, methane, and other gases believed at the time to have been present on early Earth. They found that they could produce amino acids and other important building blocks of life.
Today, many scientists argue that the early atmosphere was dominated by other gases, such as carbon dioxide. But experiments in recent years have shown that under these conditions, many building blocks of life can be formed. In addition, comets and meteorites may have delivered organic compounds from space.
Just where on Earth these building blocks came together as primitive life forms is a subject of debate. Starting in the 1980s, many scientists argued that life got its start in the scalding, mineral-rich waters streaming out of deep-sea hydrothermal vents. Evidence for a hot start included studies on the tree of life, which suggested that the most primitive species of microbes alive today thrive in hot water. But the hot-start hypothesis has cooled off a bit. Recent studies suggest that heat-loving microbes are not living fossils. Instead, they may have descended from less hardy species and evolved new defenses against heat. Some skeptics also wonder how delicate RNA molecules could have survived in boiling water. No single strong hypothesis has taken the hot start's place, however, although suggestions include tidal pools or oceans covered by glaciers.
Research projects now under way may shed more light on how life began. Scientists are running experiments in which RNA-based cells may be able to reproduce and evolve. NASA and the European Space Agency have launched probes that will visit comets, narrowing down the possible ingredients that might have been showered on early Earth.
Most exciting of all is the possibility of finding signs of life on Mars. Recent missions to Mars have provided strong evidence that shallow seas of liquid water once existed on the Red Planet--suggesting that Mars might once have been hospitable to life. Future Mars missions will look for signs of life hiding in under-ground refuges, or fossils of extinct creatures. If life does turn up, the discovery could mean that life arose independently on both planets--suggesting that it is common in the universe--or that it arose on one planet and spread to the other. Perhaps martian microbes were carried to Earth on a meteorite 4 billion years ago, infecting our sterile planet..."
oo:
