Latest
 
  • All Share : 50899.66
    DOWN -1.13%
    Top40 - (Tradeable) : 44397.13
    DOWN -1.26%
    Financial 15 : 14529.29
    DOWN -1.16%
    Industrial 25 : 67308.62
    DOWN -1.04%
    Resource 10 : 30764.74
    DOWN -1.94%

  • ZAR/USD : 13.4643
    UP 0.06%
    ZAR/GBP : 17.4736
    DOWN -0.07%
    ZAR/EUR : 15.0907
    UNCHANGED0.00%
    ZAR/JPY : 0.1335
    UNCHANGED0.00%
    ZAR/AUD : 10.3093
    UNCHANGED0.00%

  • Gold US$/oz : 1325.8
    DOWN -0.09%
    Platinum US$/oz : 1024
    UNCHANGED0.00%
    Silver US$/oz : 19.04
    DOWN -0.42%
    Palladium US$/oz : 697
    DOWN -0.14%
    Brent Crude : 46.08
    DOWN -0.35%

  • All data is delayed by 15 min. Data supplied by Profile Data
    Hover cursor over this ticker to pause.

Wed Sep 28 03:46:49 CAT 2016

Old rocks, new ideas

Shaun Smillie | 02 March, 2016 06:26
It looks like a cool place to live - but will our grandchildren still think so? Picture: REUTERS/NASA
"Earth and Mars would have been similar then," De Wit said. 'What we have in South Africa is a unique record that the environment for life was already there.' File photo
Image by: REUTERS/NASA

Once it was thought that Earth's earliest oceans were piping hot but new evidence suggests that they were cold - and this could change our understanding of how life began.

The evidence for these cold seas comes from a study of rocks in the Barberton Greenstone Belt, in Mpumalanga.

Scientists previously thought that 3.5billion years ago the planet's oceans were very hot - at between 30C and 80C - and that it was from them that early life sprang.

But through oxygen-isotope analysis of hundreds of rock samples, some believed to have been formed in glaciers, researchers now believe the opposite is true.

"These Barberton rocks formed near the equator - but there were glaciers. This is not at the poles, so this was a cold earth," said Maarten de Wit, a geologist at Nelson Mandela Metropolitan University, who was a co-author of the paper published in the Journal of Science Advances.

He said the probability of a cold Earth made sense because the sun then radiated less heat than today.

It was in the same rock formations that scientists found the earliest known evidence of life. These were microscopic tubular structures that also date back to 3.5billion years. Scientists suggested then that they evolved next to hot thermal vents.

"My best estimate is that these seas would have been at close to 0C, maybe -1C or -2C," said De Wit.

He said that with life possibly emerging from a very cold environment scientists might have to rethink evolution, and a frigid start to life on Earth bettered the odds that life sprang up elsewhere in the solar system.

"Earth and Mars would have been similar then," De Wit said. "What we have in South Africa is a unique record that the environment for life was already there."

SHARE YOUR OPINION

If you have an opinion you would like to share on this article, please send us an e-mail to the Times LIVE iLIVE team. In the mean time, click here to view the Times LIVE iLIVE section.