Some say life was brought to Earth by aliens. Beyond theories that seem depicted from a SF movie, it looks like early life indeed appeared in some extraterrestrial conditions. Geologists have encountered 1.43 billion-year-old fossils of deep-sea microbes, enhancing the theory that life may have originated on the bottom of the ocean.

The old black smoker chimneys, found in a Chinese mine, are 1 billion years older than similar fossils previously detected and are nearly similar to the archaea- and bacteria-harboring structures encountered today on sea beds.

"These are remnants of the oldest living types of life forms on the planet. The fossils offer "tantalizing suggestions" that life developed near deep-sea hydrothermal vents and not in shallow seas, as other evidence hints. " said co-researcher Timothy Kusky, a geologist at Saint Louis University.

Black smoker chimneys appear around submerged openings in the Earth's crust (corresponding to volcanoes on land) that spill out minerals into water warmed at temperatures as high as 752 degrees Fahrenheit (400 degrees Celsius). Microbes that do not depend on sunlight or oxygen colonize the fragile chimneys around the vents, feeding on dissolved minerals.

"Some people like to call it life in extreme environments. These bacteria pretty much live on a different planet compared to conditions we live in," Kusky told LiveScience.

The stony chimneys can be over 50 ft (15 m) tall, but getting even a modern chimney sample is very tricky, as they're fragile and usually crumble when touched.

"This discovery offers scientists valuable on-land samples for geological and geo-biological research," Kusky added.
Some of the fossil chimneys were 1m (3 ft) long.

"The age and size of the chimneys will help scientists understand how ancient hydrothermal vent growth and the development of life on the sea floor might be interconnected." he said.

Still, the most ancient life forms known till now are 3.5 billion-year-old, dome-shaped clumps of bacteria ("stromatolites"), encountered in Western Australia and which pointed to an origin for life in shallow seas. Still, the stromatolites do not offer a final response.

"They tell us life existed that long ago, but as to where it originated remains an open question. Black smoker fossils are just as inconclusive about the origin of life , but the new finding significantly pushes back the known reign of deep-sea microbes. Personally, a deep-sea origin of life strikes me as a very good possibility," said Ed Mathez, a geologist and curator at the American Museum of Natural History in New York, not involved in this research.

"In the end, there may yet be even older black smoker chimney fossils waiting to be discovered. So far, these fossils provide oldest evidence for deep-sea life," said Kusky.