'Goldilocks' zone of life in space far bigger than originally thought

Washington, December 31 (ANI): Scientists have determined that the "Goldilocks" zone, a region in space where conditions are not too hot and not too cold for life to exist, is far bigger than originally thought, and extends into our solar system as well.

"When people talk about 'habitable zones', they mean where there's liquid water on the surface. But there's liquid water elsewhere in the solar system; it's buried under thick sheets of ice on moons," Francis Nimmo, a planetary scientist with the University of California at Santa Cruz, told Discovery News.

Nimmo is among a growing cadre of scientists who believe the search for life beyond Earth should be focused on selected moons of Jupiter and Saturn, where liquid oceans or lakes are believed to exist beneath the frozen ground.

In addition to water, organic molecules, which could have been deposited on the surface by crashing comets, somehow would have to get through the thick shells of ice for life to form, a situation that puts Saturn's geyser-spewing moon Enceladus at the top of Nimmo's list of potential spots for life.

"It looks like the geysers are coming from an ocean, which means that it's in contact with the surface," Nimmo said.

It also would be far easier to get a water sample from Enceladus, which has plumes of water vapor, ice and particles shooting more than 300 miles off its surface, than from other moons, such as Jupiter's Europa, where a massive ocean is believed to be buried beneath a thick icy crust.

"If we go to Enceladus, we essentially get a free sample," said Nimmo, who presented a paper at the American Geophysical Union conference earlier this month about how the properties of ice impact the habitability of moons in the outer solar system.

"There aren't any bad choices," said John Spencer with the Southwest Research Institute in Boulder, Colorado.

"These places look habitable, but we don't know if there's some fatal flaw. Maybe there's not enough energy in the Europa ocean, or maybe the hotspots of Enceladus freeze over," he said.

"Or maybe, you can have perfect conditions, but life requires molecules coming together at all the right moments," Spencer told Discovery News. (ANI)