Biology

UCLA findings suggest life on Earth started much earlier than we thought

UCLA findings suggest life on ...
Zircons like these were analyzed as part of the UCLA study
Zircons like these were analyzed as part of the UCLA study
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Zircons like these were analyzed as part of the UCLA study
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Zircons like these were analyzed as part of the UCLA study

New findings from a team of geochemists at the University of California, Los Angeles (UCLA) indicate that life on our home planet started hundreds of millions of years earlier than previously thought. The discovery was made when looking at ancient zircon crystals, and could change our understanding of early Earth.

The research team, lead by postdoctoral scholar Elizabeth Bell, made the new discovery when studying a large group of zircons – more than 10,000 in total. Zircons are useful tools for such study, as they harbor well-preserved material from their immediate environment, meaning they can be used as time capsules, providing a glimpse at the ancient past.

Of the thousands of zircons in the study, 79 were picked out for in-depth analysis. They were examined using a technique known as Raman spectroscopy, a method that details the chemical and molecular makeup of samples, showing the data in three dimensions.

The tests were carried out in the hope of finding carbon – a key ingredient for life on Earth. The spectroscopy analysis whittled things down, and out of the 79 zircons, two were found to contain a pure form of carbon known as graphite.

So, what's so exciting about finding graphite in two zircons? Well, the mineral time capsules in question are 4.1 billion years old, making them some 300 million years older than the previous estimate for the earliest life on Earth. The findings show evidence of life not long after the formation of the planet 4.54 billion years ago, and before the period of bombardment that occurred around 3.9 billion years ago. That bombardment would have wiped out any earlier life, but it restarted very quickly.

"Life on Earth must have started almost instantaneously," said study co-author Mark Harrison. "With the right ingredients, life seems to form very quickly."

Bell concisely summed up the significance of the findings, stating simply that, in light of the discovery, "We need to think differently about the early Earth."

The researchers published the findings of their study in the journal Proceedings of the National Academy of Sciences.

Source: UCLA

10 comments
Racqia Dvorak
Because there was graphite in crystals that means life was there? Nonsensical cry out for research funds.
Rumata
"Life on Earth must have started almost instantaneously," Yeah, it took only some hundreds of millions of years to start. I can call that really fast :-)))
Cuckoo
I'm obviously missing something important here. But how does graphite = life?
Kysa
Graphite = carbon = building lock for life. Carbon or silicon are the two elements essential for life to occur. This research shows that carbon/graphite was in existence on the earth a lot earlier than first thought equating to the possibility that life began forming a lot earlier than first thought.
pslamont
Carbon has 4 valence electrons. Therefore it can simultaneously bond with oxygen, nitrogen, and hydrogen. So, such carbon atoms allow for the building of arbitrarily long complex molecules and polymers essential for life.
Brooke
Plants use photosynthesis to convert CO2 into carbon. The ratio of C12 to C13 can be shown to indicate carbon formed by a plant. https://en.wikipedia.org/wiki/Carbon-13#Uses_in_earth_science The key problem was making sure that the carbon they were analyzing was sealed inside (no cracks)the Zircon and not on it's surface. The videos show that's the case. http://www.pnas.org/content/suppl/2015/10/15/1517557112.DCSupplemental
Christian Lassen
Am I still missing something? Carbon would've been here since the earth was formed, in various forms, including graphite. Why is it special to find graphite? We've seen in other places how even the freezing of ice crystals can polymerize substances that don't integrate into the crystal structure. Why is it so unusual to find carbon doing the same thing among other crystals?
Robert in Vancouver
But Al Gore said the science was settled. So why are we even doing any more research into anything? If climate science is settled simply because Al Gore's said it was a few years ago, science should be considered as settled in every other field where honest research and debate has been going on for hundreds of years.
Doug Selsam
This is very unscientific, nothing but disconnected dots. It does not show that life existed on Earth at that date. It just shows carbon was here. Of COURSE carbon was here. How could it not be? Carbon is well-known to exist throughout the entire universe. These people implying that previously we thought there was no carbon here at that time? As though there was a theory of how the Earth could have first formed completely devoid of carbon, and then later there was a miraculous rain of carbon onto a previously-carbon-free Earth? I'm not aware of any such theory. It seems more likely that carbon has always been on earth, just as it is seen in stars and so many meteorites. The authors of this nonsense seem to extrapolate two (2) dumb theories: 1)that the mere presence of graphite = life. (OK so I guess my pencil lead must be alive.) 2)that there was previously some reason to believe that there was no carbon on Earth before 3.9 billion years ago. (And how could Earth form with no carbon, in a universe full of carbon?) It seems to ignore the previous reasoning for the later date of 3.9 billion years. Was part of the previous reasoning that there was no carbon on Earth until 3.9 billion years ago? "Life on Earth must have started almost instantaneously," said study co-author Mark Harrison. OK I am not seeing the chain of reasoning that would support that statement. You found carbon so that proves the presence of carbon instantaneously results in life? Or how about: "With the right ingredients, life seems to form very quickly." OK great, but finding some graphite does not even begin to imply that, let alone prove it. Bell concisely summed up the significance of the findings, stating simply that, in light of the discovery, "We need to think differently about the early Earth." Why do we need to think differently? Who ever even implied that there was no carbon on Earth before 3.9 billion years ago? Either this is complete bunk, or else this article left out some critical link of the original reasoning. The only way this story could be true is if they left out the main point, otherwise it simply makes no sense.
Magrim
Robo get a life, doug lrn2read