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Earth was like Mars? Experts find fossils in Greenland dating back to 3.7 Billion Years

Greenland stromatolites find can make Mars look even more promising than before as a potential abode for past life

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Allen Nutman (L) of the University of Woollongong and Vickie Bennet of the Australian National University hold a specimen of 3.7 billion-year-old fossils found in Greenland in Canberra, Australia, August 23, 2016. Picture taken August 23, 2016. Image source: Reuters
  • Stromatolites-fossilized communities of bacteria were supposedly found in south-west Greenland, these pre date fossils by 220 million years
  • There can be staggering implications of this find, one of them being a higher probability of life in Mars
  • The Earth was probably similar to Mars when stromalites started growing

September 1,2016– Fossils as defined in a dictionary are the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form. In simpler terms, fossils help us understand the existence of life that dates back to some billion years.

In recent news, the earliest fossil evidence of life on Earth has been found in rocks 3.7 billion years old in Greenland. This in way raises the chances of life on Mars aeons ago when both planets were similarly desolate, scientists said on Wednesday.

The experts found tiny humps, between one and 4 cm (0.4 and 1.6 inches) tall, in rocks at Isua in south-west Greenland that they said were fossilized groups of microbes similar to ones now found in seas from Bermuda to Australia.

If confirmed as fossilized communities of bacteria known as stromatolites – rather than a freak natural formation – the lumps would pre-date fossils found in Australia as the earliest evidence of life on Earth by 220 million years.

“This indicates the Earth was no longer some sort of hell 3.7 billion years ago,” lead author Allen Nutman, of the University of Wollongong, told Reuters of the findings that were published in the journal Nature.

“It was a place where life could flourish.”

Earth formed about 4.6 billion years ago and the relative sophistication of stromatolites indicated that life had evolved quickly after a bombardment by asteroids ended about 4 billion years ago.

“Stromatolites contain billions of bacteria … they’re making the equivalent of apartment complexes,” said Martin Van Kranendonk, a co-author at the University of New South Wales who identified the previously oldest fossils, dating from 3.48 billion years ago.

At the time stromatolites started growing in gooey masses on a forgotten seabed, the Earth was probably similar to Mars with liquid water at the surface, orbiting a sun that was 30 percent dimmer than today, the scientists said.

Those parallels could be a new spur to study whether Mars once had life, the authors said.

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“Suddenly, Mars may look even more promising than before as a potential abode for past life,” Abigail Allwood, of the California Institute of Technology, wrote in a commentary in Nature.

The Greenland find was made after a retreat of snow and ice exposed long-hidden rocks. Greenland’s government hopes that a thaw linked to global warming will have positive spin-offs, such as exposing more minerals.

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Nutman said the main controversy was likely to be that the fossils were in metamorphic rocks, reckoned to have formed under huge stress with temperatures up to 550 degrees Celsius (1,022°F) – usually too high to preserve any trace of life.

Still, Van Kranendonk told Reuters that dried-out biological material could sometimes survive such a baking, adding he was “absolutely convinced” by the Greenland fossils. (Reuters)

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    Why are we always talking about Mars? Why don’t we show interest towards other planets?

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Earth’s Mantle May Have Generated its Early Magnetic Field: Research

Magnetic fields form on Earth and other planets that have liquid, metallic cores, rotate rapidly, and experience conditions that make the convection of heat possible

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In a study appearing in the journal Earth and Planetary Science Letters, Scripps Oceanography researchers Dave Stegman, Leah Ziegler and Nicolas Blanc provide new estimates for the thermodynamics of magnetic field generation within the liquid portion of the early Earth's mantle. Pixabay

Where did our planet’s magnetic field come from? According to new research, Earth’s mantle, not its core, may have generated planet’s early magnetic field.

The Earth’s mantle is made of silicate material that is normally a very poor electrical conductor.

Therefore, even if the lowermost mantle were liquid for billions of years, rapid fluid motions inside it wouldn’t produce large electrical currents needed for magnetic field generation, similar to how Earth’s dynamo currently works in the core.

In a study appearing in the journal Earth and Planetary Science Letters, Scripps Oceanography researchers Dave Stegman, Leah Ziegler and Nicolas Blanc provide new estimates for the thermodynamics of magnetic field generation within the liquid portion of the early Earth’s mantle.

Stegman’s team asserted the liquid silicate might actually be more electrically conductive than what was generally believed. “Currently we have no grand unifying theory for how Earth has evolved thermally,” Stegman said.

“We don’t have this conceptual framework for understanding the planet’s evolution. This is one viable hypothesis.” New research lends credence to an unorthodox retelling of the story of early Earth first proposed by a geophysicist at Scripps Institution of Oceanography at University of California San Diego.

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The Earth’s mantle is made of silicate material that is normally a very poor electrical conductor. Pixabay

It has been a bedrock tenet of geophysics that Earth’s liquid outer core has always been the source of the dynamo that generates its magnetic field. In another paper, Arizona State geophysicist Joseph O’Rourke applied Stegman’s concept to consider whether it’s possible that Venus might have at one point generated a magnetic field within a molten mantle.

Magnetic fields form on Earth and other planets that have liquid, metallic cores, rotate rapidly, and experience conditions that make the convection of heat possible.

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If Stegman’s premise is correct, it would mean the mantle could have provided the young planet’s first magnetic shield against cosmic radiation. It could also underpin studies of how tectonics evolved on the planet later in history.

“If the magnetic field was generated in the molten lower mantle above the core, then Earth had protection from the very beginning and that might have made life on Earth possible sooner,” Stegman said. (IANS)