Washington: A hail of meteorites from space could have sparked life on Earth, say scientists. Although it's widely accepted that a meteor strike about 65 million years ago killed off the dinosaurs, the scientists say a hail of the massive rocks far earlier in Earth's history may have created ideal conditions for primordial life forms.

"When people think of impact events and life, probably 99 per cent think of the extinction of dinosaurs. There're always destructive effects but afterward, particularly if you are a microbe, these impacts can be beneficial," Gordon Osinski at the University of Western Ontario, the lead scientist, said.

During a time known as the Early Bombardment, when the Earth was a half-billion years into its 4.5 billion-year history, a barrage of meteorites smashed into the young planet, which could have provided the necessary materials for a hydrothermal system, similar to today's deep-sea vents.

"All you need for hydrothermal activity is a heat source, plus water," Osinski was quoted by the 'Space.com' as saying.
The colossal meteor and the energy of its impact would have melted rocks for many hundreds of miles, providing the heat and water, whether as precipitation, ice or contained in small amounts in Earth's surface, would have been plentiful.

"It would cool slowly over time, but the time scale varies tremendously. The bigger the crater, the bigger the heat source, the more slowly it cools. How long they last is one of the big unknowns, but for smaller craters, it's tens of
thousands of years," Osinski said. And it turns out that hydrothermal systems are a big suspect in the hunt for the birthplace of life on Earth, say the scientists.

"The reason hydrothermal systems are thought to be so interesting is you come to the base of the tree of life, and all of those organisms are thermophiles," he said.

Osinski explained heat-loving organisms that thrive in the scalding temperatures of 140 to 176 degrees Fahrenheit found in hydrothermal systems such as Yellowstone's volcano- heated lakes or hydrothermal vents along the seafloor.

"Basically, we don't know where life originated. It's a big open question on Earth. But hydrothermal systems have been suggested as places. You have energy, food and water – all the key ingredients of life," he said.

(Agencies)