SA key to finding life out there

South Africa is uniquely placed to help lead global advances in humanity's search for extraterrestrial life, a renowned Nasa scientist said at a gathering of fossil hunters in Johannesburg at the weekend.

"Life on Earth serves as a guide to find potentially habitable environments beyond Earth, and it's really just South Africa, and a little of Canada, Australia and Greenland, where you can find the earliest geological evidence of the origin of life," said Dr Kevin Hand, deputy chief scientist for solar-system exploration at Nasa's Jet Propulsion Laboratory, in California.

Speaking at the Palaeontological Society of Southern Africa's 18th biennial conference at the Wits Great Hall, Hand in a special public lecture looked at how Earth's past and present can help the search for life on other planets. The event, which ends today, is hosted by Wits University's Evolutionary Studies Institute.

"South Africa's geological record is evidence of the important transition from microbial to multicellular life, of which we still understand very little," said Hand.

A planetary scientist and astrobiologist, 39-year-old Hand specialises in studying some of Earth's most extreme environments. He has visited South Africa on several occasions since 1999 for research on meteorite impact sites, such as the 2-billion-year-old Vredefort Dome."The dome is a time capsule through which we can understand our own planet's history and the evolution of our solar system.

"The impact of the Vredefort meteor could well have ejected Earth rocks to Mars. During that time microbes were already photosynthesising - and it might have been a period when Mars was wet and warm."

That would mean that conditions on Mars might have been right to harbour the life transported from Earth.

Hand's career is dedicated to exploring the possibilities of life on other planets - but the extraterrestrial life he hopes to find is not necessarily intelligent. Yet.

"Finding even the simplest single-cell microbe beyond Earth would be revolutionary," he said. "But who knows, if the global ocean on Europa, one of Jupiter's moons, gave rise to life billions of years ago, and the chemistry is sufficient, that life might have become more complex."

As for finding highly evolved life, Hand said: "We're only just discovering potentially Earth-like planets around stars. Maybe they are home to intelligent communicating civilisations."

Our universe holds billions of galaxies in which technologically advanced communities might be hidden. But for now the limits of interplanetary logistics force us to focus on our own solar system, in which Europa is "prime real estate" for finding life.

"Its sub-glacial ocean holds three times the volume of all Earth's water, and where we find water we generally find life. Microbes can thrive in the most bizarre conditions."

Finding life beyond Earth would redefine everything we think we know about life.

"It would initiate a revolution in biology - especially if we can find life in a world like Europa and look at what makes it tick. Is it based on the conventional tree of life - DNA, RNA and proteins . or is there some other game in town?"