NASA, ESA, J. Hester, A. Loll (ASU) Posted on 11/16/2020 7:22:17 AM PST by Red Badger
NASA, ESA, J. Hester, A. Loll (ASU)
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Supernovas may have affected the Earth’s climate in the last 40,000 years.
Tree-ring data suggests supernovas caused spikes in radiocarbon.
Could the next nearby supernova cause a collapse of civilization?
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Dendrochronology is a fancy word for tree-ring dating, where the age of a tree can be determined by the number of growth rings across its trunk. But there’s a lot more to learn from looking at a tree’s rings than simply its age.
Like fingerprints, tree rings give scientists clues to what the world was like when a tree was alive. By studying tree rings, we can determine when the tree lived, the climatic conditions through which it lived, and possibly, what was happening in the universe at the time.
In a new study published in the International Journal of Astrobiology, geoscientist Robert Brakenridge, of the University of Colorado, suggests a number of supernovas may have left their mark on life on Earth over the last 40,000 years. By poring through countless tree ring records and matching them to known supernova events, Brakenridge discovered that of the eight recent supernovas he studied, each one seemed to leave their mark on trees.
The alarming part? Four of those supernovas may have significantly disrupted Earth’s climate, leading scientists to wonder what the next supernova event might mean for civilization.
Supernovas are brilliant explosions caused by the deaths of massive stars. They’re the most massive and energetic explosions known to science, sometimes shining brighter than the combined light of their galaxies. The overwhelming energy released in such an explosion has caused scientists to worry that a nearby supernova could wipe away life on Earth. But even distant supernovas could pose a risk by damaging Earth’s protective ozone layer, Brakenridge said in a press release.
“These are extreme events, and their potential effects seem to match tree ring records," he said.
Brakenridge’s research relies on the scientific art of radiocarbon dating. When carbon atoms in Earth’s atmosphere get struck by cosmic rays from space, they can form a radioactive isotope called carbon-14, or radiocarbon. Some of those carbon isotopes get taken in by plants and animals, leaving a lasting fingerprint that scientists use to date their remains.
When dendrochronologists look at the amount of radiocarbon in tree rings, they expect a steady decline in the isotope as they look at older rings. To their surprise, scientists have discovered a number of cases where the concentration of radiocarbon in tree rings spike. Without any earthly explanations, scientists have looked toward the cosmos for answers.
Many scientists believe these spikes may be caused by solar activity. Violent solar flares can cause the ejection of plasmas and solar particles that bombard Earth’s upper atmosphere and may explain the spikes in radiocarbon. But a handful of scientists believe the answer lives farther out, beyond the comforts of our solar system.
“We’re seeing terrestrial events that are begging for an explanation,” Brakenridge said. “There are really only two possibilities: A solar flare or a supernova. I think the supernova hypothesis has been dismissed too quickly.”
To dig deeper, Brakenridge created a list of recorded supernovas that occurred near Earth over the last 40,000 years. When he compared these records to the carbon fingerprints left in tree rings, eight of the closest matching supernova events coincided with spikes in radiocarbon.
The last time scientists observed a supernova with the naked eye was in 1604, when Johannes Kepler described SN 1604 (Kepler’s Supernova) in De Stella Nova. And the earliest account of a supernova, some believe, is a stone carving in Burzaham, India. The artwork, estimated to be between 4,000 and 6,000 years old, depicts a hunting scene where two people hunt under a sky with two suggestively bright celestial objects. Some researchers think this may represent a supernova estimated to be as bright as the moon that occurred during the same time period.
VIDEO AT LINK.........................
Astronomers are able to record these past explosions by observing the colorful nebulas they leave behind and estimate when they occurred. However, this method of dating supernovas isn’t an exact science, and estimates can be off by as much as 1,500 years.
This goes to show that when looking at some historical records, scientists rarely can be certain. We may not know the real danger a nearby supernova poses to civilization until it happens. Let’s just hope that doesn’t take place for a very, very long time.
I was very clear in my reply
No such thing.......................
I was very clear in my original post.
Michael G. L. Baillie is Professor Emeritus of Palaeoecology at Queen's University of Belfast, in Northern Ireland. Baillie is a leading expert in dendrochronology, or dating by means of tree-rings. In the 1980s, he was instrumental in building a year-by-year chronology of tree-ring growth reaching 7,400 years into the past.
Upon examining the tree-ring record, Baillie noticed indications of severe environmental downturns around 2354 BC, 1628 BC, 1159 BC, 208 BC, and AD 540. The evidence suggests that these environmental downturns were wide-ranging catastrophic events; the AD 540 event in particular is attested in tree-ring chronologies from Siberia through Europe and North and South America
Petrified? But then would the rings still be distinguishable for chemical analysis as they are literally transformed into stone?
You can see the rings in well preserved petrified wood.
Yes, you can see them. I’m just wondering about the distribution of radioactive material when minerals start replacing cellulose during the process of petrifying. Can you still rely on readings that would normally concentrate in an annual growth band?
Whether warming is caused by supernovae or sunspot activity, it's evident we go through phases of warming and cooling.
The Medieval Warming Period occurred for a few centuries, crops yielded more, people flourished, sea levels rose, all of that is fact.
Then there was a cooling period over centuries sometimes referred to as The Little Ice Age. Crops yielded less, there were famines, sea levels receded (the ancient city Ephesus of the New Testament used to be a port city, now it's a few miles from the sea), all of that is fact.
Absolutely nobody should be surprised at the warming that's occurred for the past two centuries as we've come out of the Little Ice Age and begin another warming period. In fact, we should embrace it.
Correction: “man-made supernovas, and the only answer is less freedom”
If you know each ring corresponds to one years growth, and you can match wide-narrow 'bar codes' from an early portion a tree growing today to a late portion of a tree long dead (say, roof beams in an Anasazi dwelling), and the 'bar code' close to the heart of that to a deep water preserved keel from a Roman era ship, and so on, you know exactly how old a piece of wood large enough to have enough rings really is. If it still has the bark, you can even tell the season, it died, whether it fell in spring or fall!
and higher taxes..................
Thanks Red Badger.
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The rest of the Iron-60 keyword, chrono:
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When I went to college For physics I got this question from my college professor...
I believe that empty space is not so empty. I suspect there are many clumps of matter that never formed stars, that may even have planets.
Especially with supernovas sending out chunks of matter all over the place formed of heavy elements .
Olber’s Paradox, the Big Bang, and the expanding universe.
Because there are not that many stars as we think?
You go big and it is mostly space.
You go little and it is mostly space.
No matter which way you go matter is scarce.
Life is even more scarce.
And sentient life is the rarest thing in the universe.
One little nitpick on this article. Carbon-12 is not turned into Carbon-14. There is no neutron capture involved. Nitrogen-14, the most common isotope, is turned into Carbon-14, which in turn beta decays back to Nitrogen-14.
I wonder just how many copies of the “International Journal of Astrobiology” gets mailed each month or is it just an on-line subscription now.
Astrobiology probably doesn’t have a lot of specimens to study.......................yet............
In addition to volcano caused cold weather and shadow, there are also layers of volcanic ash and lava. Those layers can be tested for age and things under or above them are older or younger. Where there are multiple layers separated by centuries, one can find and date old trees approximately and see the between eruption conditions recorded.
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