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Earth Science

Scientists May Have Found the Earliest Evidence of Life On Earth (sciencemag.org) 71

Posted by samzenpus from the in-the-beginning dept.
sciencehabit writes with news that UCLA scientists have found evidence that life likely existed on Earth at least 4.1 billion years ago, 300 million years earlier than previously thought. Science reports: "When did life on Earth begin? Scientists have dug down through the geologic record, and the deeper they look, the more it seems that biology appeared early in our planet's 4.5-billion-year history. So far, geologists have uncovered possible traces of life as far back as 3.8 billion years. Now, a controversial new study presents potential evidence that life arose 300 million years before that, during the mysterious period following Earth's formation. The clues lie hidden in microscopic flecks of graphite—a carbon mineral—trapped inside a single large crystal of zircon. Zircons grow in magmas, often incorporating other minerals into their crystal structures of silicon, oxygen, and zirconium. And although they barely span the width of a human hair, zircons are nearly indestructible. They can outlast the rocks in which they initially formed, enduring multiple cycles of erosion and deposition."
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Scientists May Have Found the Earliest Evidence of Life On Earth More

Scientists May Have Found the Earliest Evidence of Life On Earth

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  • Here. It's right here.

    • Re:Where's the evidence!? (Score:5, Interesting)

      by The Real Dr John ( 716876 ) on Tuesday October 20, 2015 @08:25AM (#50764625) Homepage

      It's tough to get a good discussion on biology going here at /. This is a really interesting find if it holds up. The structures they found are interesting, and have characteristic features that don't seem like they could have been produced by geological means. But still, I think they have their work cut out for themselves to find more samples, and confirm that these aren't just some very odd geological artifacts.

    • Re: (Score:2)

      by msauve ( 701917 )
      Yeah. No link, just a claim. And an odd one at that - although Life As We Know It requires carbon, carbon certainly doesn't require life to form.

      Also see this [nature.com].

  • No one reads the article so... (Score:5, Insightful)

    by burtosis ( 1124179 ) on Tuesday October 20, 2015 @08:34AM (#50764685)
    Let's not even include a link to it!

  • Actual article link (Score:5, Informative)

    by burtosis ( 1124179 ) on Tuesday October 20, 2015 @08:38AM (#50764699)
    link to article [ucla.edu]

  • UCLA News (Score:4, Informative)

    by ath1901 ( 1570281 ) on Tuesday October 20, 2015 @08:48AM (#50764749)

    Haven't found any scientific article yet but here is the news page from UCLA:
    http://newsroom.ucla.edu/relea... [ucla.edu]

    In short, they found graphite in a crystal and the graphite has a carbon 12 to carbon 13 ratio which indicates biological origin.

    So, the current status is "plausible" but if someone comes up with another explanation it is "busted".

  • Right in the middle of the Hadean period. (Score:5, Insightful)

    by dotancohen ( 1015143 ) on Tuesday October 20, 2015 @08:51AM (#50764769) Homepage
    Note that 4.1 Ga is right in the middle of the Hadean period, when the Earth was still settling into layers and the crust and oceans were just forming. No distinct core or mantle yet, and the moon was a ring of rock encircling the Earth. This is half a million years before plate tectonics, before even prokaryota (micros without cell nuclei) developed.

    These clues might just tell _how_ cellular reproduction and upwards energy gradients (i.e. life) began, not just _when_.

    • Re: (Score:2)

      by martas ( 1439879 )
      I presume you mean "half a billion"

      • I presume you mean "half a billion"

        Yes, half a billion. Thank you. I was trying to put the discovery into perspective, and this correction shows just how hard it is to grasp the vast time periods involved.

    • Re: (Score:1)

      by Anonymous Coward

      No. Given its size and temperature, the earth would have been differentiated almost immediately, with oceans present at 4.4Gy. The moon would have been completely formed, though very hot and active. A ring moon would have been very short lived. Tectonics, of some form, in the presence of water would have started almost immediately, and been very vigorous.

      • Thank you for commenting. I understand that oceans were significant only at the end of the Hadean, 3.8 Ga. The moon I'm not sure about other than the fact that it was also formed during the Hadean. Plate tectonics though, from what I understand, only started after 3.8 Ga along with the oceans.

        If the oceans and plate tectonics, along with the differentiated interior, did in fact develop 4.4 Ga, then why is the period that we call Hadean said to have ended only at 3.8 Ga?

        Thank you for your clarifications!

  • Using "mysterious" in a scientific publication. Ever.

  • Somewhere in Kentucky.... (Score:1)

    by Anonymous Coward

    Ken Ham is curling up in a ball chanting "6000 years, 6000 years, 6000 years!"

  • Panspermia (Score:3)

    by PopeRatzo ( 965947 ) on Tuesday October 20, 2015 @09:46AM (#50765099) Journal

    I'm not saying it was aliens, but...

  • Ok aside from the fact that it took me a few minutes to figure out where the article link was (I nearly posted some critique on the editor for not including it), how do you think this is going to work Dice? I mean it's one thing to turn Slashdot into a typical trashy blog, but even they follow conventions of inline links.

    What happens when you suddenly include multiple articles or multiple sources in your posts? Who gets to go in the title, the one who paid the most?

    I can't believe how hard to use this site

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