These ecosystems contained various types of fish, worms, crabs, bacteria and other organisms which had found a way to survive in a cold, hostile environment without energy input from sunlight. Because life had been found to exist where it previously was thought unable to, many scientists began to ask questions as to whether or not this was where life may have originated on the earth. On the molecular level, the chances of life originating at deep sea thermal vents is not likely. It is known that organic molecules are unstable at high temperatures, and are destroyed as quickly as they are produced. The temperatures at this gradient would be suitable for organic chemistry to occur.
Debates still remain, however, as to the gradient's effectiveness in producing organic compounds.
In the early twentieth century, a Swedish chemist named Svente Arrhenius developed a theory called panspermia. Arrhenius' theory accounted for life's origins by simply stating that life did not originate on the Earth, but originated elsewhere in the universe. He believed that cellular life reached the Earth hiding inside a meteor which hit the Earth long ago. The odds of an organism surving inside a meteor for thousands of years, however, are not high. It is even less likely that organisms would be able to withstand the high energy impacts of bolides into the Earth or other planetary objects.