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The Cosmic Story of Carbon-14
Starts with a Bang ^ | 6/4/12 | Ethan Siegel

Posted on 06/05/2012 12:48:06 AM PDT by LibWhacker

“Life exists in the universe only because the carbon atom possesses certain exceptional properties.” -James Jeans

Here on Earth, every living thing is based around four fundamental, elemental building blocks of life: hydrogen, oxygen, nitrogen and, perhaps most importantly, carbon.

DNA + Nanotubes

Image Credit: Robert Johnson / University of Pennsylvania.

From diamonds to nanotubes to DNA, carbon is indispensable for constructing practically all of the most intricate structures we know of. Most of the carbon in our world comes from long-dead stars, in the form of Carbon-12: carbon atoms containing six neutrons in their nucleus. About 1.1% of all carbon is Carbon-13, with one extra neutron. But there is another form of carbon that, while not at all abundant, is definitely worth talking about.

Carbon Isotopes

Image credit: Press & Silver.

Carbon-14, or carbon atoms with eight neutrons in their nuclei, is unstable, and is so rare that only one-in-a-trillion carbon atoms are carbon-14. With a half-life of just over 5,000 years, any Carbon-14 atoms that were created in stars, billions of years ago, have long since decayed away into nitrogen atoms.

Carbon-14 Decay

Image credit: Steve Gagnon at Jefferson Lab.

But there are small, but not quite negligible amounts of carbon-14 present in all the organic life that we know, including in our own bodies. The way it gets here is, literally, cosmic.

Cosmic Rays

Image credit: Simon Swordy (U. Chicago), NASA.

From across the galaxy and across the Universe, from stars (including our Sun), pulsars, black holes and more, space is flooded with high-energy particles known as cosmic rays. Most frequently, cosmic rays are protons, but a handful are heavier ions and a few are even humble electrons. But once they interact with the atmosphere, look out!

Cosmic ray shower

Image credit: University of New Hampshire.

They produce showers of subatomic particles of many different types, including — for our purposes — the all important neutron. The reason neutrons are so important is because our atmosphere is 78% nitrogen, which you may remember as the thing that carbon-14 decays into.

Well, if carbon-14 can decay into nitrogen-14 and other stuff, then we can create carbon-14 by combining nitrogen-14 with the proper stuff. In this case, that happens to be a neutron, which allows us to do this:

Carbon-14 creation

Image credit: Wikimedia Commons, users NikNaks, Spacexplosion, and Sgbeer.

Once you create carbon-14, it behaves just like any other atom of carbon, readily forming CO2 (a.k.a., carbon dioxide) and mixing throughout the atmosphere and oceans, easily making its way into living organisms into a well-understood equilibrium. As far as we can tell, the levels of carbon-14 throughout the world have remained roughly constant throughout the past few millenia, so that when an organism dies and the carbon-14 decays, we can measure how long ago it became deceased by measuring the ratio of carbon-14 to its normal carbon-12.

The only major fluctuation we know of occurred when we began detonating nuclear weapons in the open air, back in the mid-20th Century. If you ever wondered why nuclear tests are now performed underground, this is why.

Radiocarbon spike

Image credit: Wikimedia Commons, user Hokanomono.

So you can imagine it came as a shock when, just yesterday, nature released a paper showing a big, short-lived spike in carbon-14 levels way back in the 8th Century! By looking at the tree rings of ancient Japanese Cedars, you can see a rise in the concentration of carbon-14 that starts in the 770s, peaks in the 780s and then falls off.

Carbon-14 spike

Image credit: Fusa Miyake, Kentaro Nagaya, Kimiaki Masuda & Toshio Nakamura, 2012.

What does this correspond to, in terms of creating this carbon-14? Well, there were no nearby supernovae that happened at that time, so that’s out. There’s no evidence of an unusually large solar flare or any other bizarre solar activity, so that can’t be the culprit, either. What this appears to correspond to, at least at this preliminary stage, is an increase in cosmic rays during the year 774-775.

Spike in Cosmic Rays

Image credit: Fusa Miyake, Kentaro Nagaya, Kimiaki Masuda & Toshio Nakamura, 2012.

Now, since we’ve been watching the skies, we’ve never seen an increase in levels like this, but it’s only recently that our sophistication in measuring the carbon-14 levels in old tree rings like this has allowed us to test this.

The follow-up? Looks like we’re going to have to unearth more old trees that can be radiocarbon-dated back to these years, and see whether they have elevated levels of carbon-14 in them. If not, then it’s conceivable that these trees are just flukes, or that there was a mistake done in the analysis. But that doesn’t seem likely; there is data from North American and European trees that this is consistent with! If this is confirmed, then there was very likely an extremely large increase in cosmic radiation over a very short period of time, the likes of which we’ve never seen or recorded, until now.

What could’ve caused an influx of cosmic rays like this? While there are many possibilities, I wouldn’t count out a relatively nearby, flaring black hole!

Black hole flare

Image credit: NASA / Goddard Space Flight Center.

The Universe may never cease to surprise us, but we may never cease, as long as we exist, to figure out exactly why it does the things that it does. How remarkable is this!

Thanks to Sarah Kavassilis for suggesting this story; it’s a great one!



TOPICS: Astronomy; Science
KEYWORDS: carbon14; catastrophism; cosmic; decay; fusamiyake; godsgravesglyphs; rays

1 posted on 06/05/2012 12:48:12 AM PDT by LibWhacker
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To: LibWhacker

Just what do neutrons do? My theory is they are akin to atomic fat.


2 posted on 06/05/2012 1:15:13 AM PDT by outofsalt ("If History teaches us anything it's that history rarely teaches us anything")
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To: SunkenCiv

/mark


3 posted on 06/05/2012 1:22:15 AM PDT by KoRn (Department of Homeland Security, Certified - "Right Wing Extremist")
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To: outofsalt

I’m probably the wrong person to ask but, as we know, like charges repel. Therefore, protons would have a difficult time forming nuclei if neutrons weren’t present to give them something to bind with. If it weren’t for neutrons, we definitely wouldn’t be here!


4 posted on 06/05/2012 1:29:36 AM PDT by LibWhacker
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To: LibWhacker

Under proposed NYC law you will be able to buy carbon-12 and carbon-13 but not carbon-14.


5 posted on 06/05/2012 1:31:24 AM PDT by Lockbox
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To: Lockbox

Assault carbon?


6 posted on 06/05/2012 2:35:33 AM PDT by ModelBreaker
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To: LibWhacker
"...showing a big, short-lived spike in carbon-14 levels way back in the 8th Century!....a rise in the concentration of carbon-14 that starts in the 770s, peaks in the 780s...."

A nuclear exchange during the Dark Ages?

7 posted on 06/05/2012 3:53:28 AM PDT by Psalm 73 ("Gentlemen, you can't fight in here - this is the War Room".)
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To: LibWhacker
Most frequently, cosmic rays are protons, but a handful are heavier ions and a few are even humble electrons

The above are charged particles and subject to magnetic forces ("Northern Lights" are formed this way).

This may be the simplest explanation (Occam's Razor) assuming it is not just a false reading or interpretation.

8 posted on 06/05/2012 4:35:47 AM PDT by Aevery_Freeman (Typed using <FONT STYLE=SARCASM> unless otherwise noted)
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To: ModelBreaker
Assault carbon?

no, jumbo size carbon

9 posted on 06/05/2012 5:15:10 AM PDT by Lockbox
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To: LibWhacker
The Doppler Effect


10 posted on 06/05/2012 5:53:27 AM PDT by Cletus.D.Yokel (Catastrophic Anthropogenic Climate Alterations - The acronym explains the science.)
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To: outofsalt
Well there is a reason why carbon 12 is abundant - 6 protons and 6 neutrons - and why carbon 11 is rare - 6 protons and 5 neutrons.

Without neutrons the nucleus of most elements would be unstable. They act as mediators of the strong force that acts to attract protons together and the electromagnetic / weak force that causes protons to repel each other.

11 posted on 06/05/2012 7:03:09 AM PDT by allmendream (Tea Party did not send GOP to D.C. to negotiate the terms of our surrender to socialism)
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To: outofsalt
Just what do neutrons do?

For one thing they make the sum of the binding "strong interaction" between hadrons (protons and neutrons) in the nucleus larger than the repelling electromagnetic force between the protons. Which makes stable nuclei possible.

12 posted on 06/05/2012 11:19:31 AM PDT by Moltke (Always retaliate first.)
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To: Lockbox

“no, jumbo size carbon”

Both equally evil. Perhaps we should note here that carbon is a key element in Carbon Dioxide, which of course is responsible for all global warming. So it should be banned for that reason too.


13 posted on 06/05/2012 12:22:35 PM PDT by ModelBreaker
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To: KoRn; StayAt HomeMother; Ernest_at_the_Beach; decimon; 1010RD; 21twelve; 24Karet; 2ndDivisionVet; ..

 GGG managers are SunkenCiv, StayAt HomeMother & Ernest_at_the_Beach
Thanks KoRn.

To all -- please ping me to other topics which are appropriate for the GGG list.


14 posted on 06/08/2012 7:10:20 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/)
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To: LibWhacker

Fairly accurate, but the reason they stopped above-ground testing had little or nothing to do with carbon.

It was the Iodine, Strontium, and Cesium radioactive isotopes (and a bit of radioactive inert gasses) that were created that put an end to open air testing.


15 posted on 06/09/2012 2:25:38 AM PDT by djf ("There are more old drunkards than old doctors." - Benjamin Franklin)
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To: LibWhacker
We Are Star Dust, We Are Golden.
We are Billion year old Carbon

16 posted on 06/09/2012 4:36:24 AM PDT by Condor51 (Yo Hoffa, so you want to 'take out conservatives'. Well okay Jr - I'm your Huckleberry)
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To: Cletus.D.Yokel
Great episode. I just started watching BBT in reruns.

C-Men

17 posted on 06/10/2012 4:51:58 PM PDT by Sawdring
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Thanks again, KoRn, just adding to the keyword, not pinging.


18 posted on 01/21/2013 11:18:54 AM PST by SunkenCiv (Romney would have been worse, if you're a dumb ass.)
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