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Gamma-Ray Burst Caused Mass Extinction?
National Geographic News ^ | 03 Apr 2009 | Anne Minard

Posted on 04/07/2009 10:17:42 AM PDT by BGHater

A brilliant burst of gamma rays may have caused a mass extinction event on Earth 440 million years ago—and a similar celestial catastrophe could happen again, according to a new study.

Most gamma-ray bursts are thought to be streams of high-energy radiation produced when the core of a very massive star collapses.

Such a disaster may have been responsible for the mass die-off of 70 percent of the marine creatures that thrived during the Ordovician period (488 to 443 million years ago), suggests study leader Brian Thomas, an astrophysicist at Washburn University in Kansas.

The simulation also shows that a significant gamma-ray burst is likely to go off within range of Earth every billion years or so, although the stream of radiation would have to be lined up just right to affect the planet.

Currently WR104, a massive star 8,000 light-years away in the constellation Sagittarius, is in position to be a potential threat, Thomas noted.

But the study, which has been submitted to the International Journal of Astrobiology, isn't necessarily sending other astrophysicists into a panic.

"There is certainly no harm in looking at what a gamma-ray burst might do if it were close enough to us, as this author has done. That's the way science works," said David Thompson, a NASA astrophysicist and deputy project director on the Fermi Gamma-ray Space Telescope.

But Thompson compares the risk to Earth from a future gamma-ray burst to "the danger I might face if I found a polar bear in my closet in Bowie, Maryland.

"It could happen, but it is so unlikely that it is not worth worrying about."

Lingering Damage

Study author Thomas' former graduate advisor, Adrian Melott, first proposed in 2004 that a gamma-ray burst near Earth wiped out Ordovician life. Since then, both researchers have been tackling pieces of the puzzle.

According to their newest models, gamma radiation from a nearby burst would quickly deplete much of Earth's protective ozone layer, allowing increased ultraviolet radiation (UV) from the sun to reach the surface.

In the longer term, chemical reactions in the atmosphere would produce dark, nitrogen-based gases that would block the sun's heat and trigger global cooling, even as the gamma rays continued to deplete ozone and let in UV rays, the authors suggest.

Some of the pollution would fall as damaging acid rain, which can severely disrupt ecosystems.

The atmosphere might be able to recover within a decade, and a rise in DNA damage caused by increased UV exposure might pass after a few months or years, the researchers note.

But other biological impacts—such as reduced ocean productivity—could linger for an unknown length of time, Thomas said.

The Trouble With Trilobites

Bruce Lieberman, a paleontologist at the University of Kansas, helped develop the initial theory about the Ordovician die-off but did not co-author the recent papers.

The prevailing idea is that an ice age caused the extinction event, he said, but he questions the completeness of that hypothesis.

"At other times there have been ice ages without mass extinctions," he said.

Furthermore, the ice age during the Ordovician was comparatively short, lasting only about 500,000 years before the climate cycled back to a warm spell—almost as if something unusual set the icy period in motion.

So far Thomas and Melott have uncovered a pattern of higher UV radiation during the Ordovician extinction that would match cosmic bombardment over the South Pole.

And Lieberman believes the disappearance of trilobites, extinct arthropods related to horseshoe crabs, could be tied to the Ordovician event.

Although most trilobites are mud-scurrying bottom dwellers, the juveniles of some species have a life stage that sends them floating in the shallow water column, making them vulnerable to higher UV radiation.

But like NASA's Thompson, Lieberman adds that worry over a future gamma-ray burst is "not the thing that's keeping me up at night."

Instead he appreciates the new work for pointing out that Earth is a vulnerable part of the cosmos.

"It gives us a new perspective on things like natural selection and adaptation.

Gamma-ray bursts are thought to be streams of high-energy radiation produced when the core of a very massive star collapses, as seen in the above artist's rendering.

An April 2009 paper suggests that a gamma-ray burst aimed at Earth may have caused a mass extinction event 440 million years ago, and that a similar celestial catastrophe could happen again.


TOPICS: Astronomy; Science
KEYWORDS: catastrophism; crevo; extinction; gamma; grb; intelligentdesign; junkscience; oldearthspeculation; radiation

1 posted on 04/07/2009 10:17:43 AM PDT by BGHater
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To: SunkenCiv

‘mass extinction event 440 million years ago, and that a similar celestial catastrophe could happen again’

catastrophism/Incredible Hulk/Don’t worry about your credit card bill ping.


2 posted on 04/07/2009 10:18:34 AM PDT by BGHater (Tyranny is always better organised than freedom)
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To: BGHater

Well that tears it.

We will need to enclose the solar system in a large sphere made of lead.

We can’t just do the planet, we need to do the whole solar system.

Lets get started now. We need to implement a lead credit program.


3 posted on 04/07/2009 10:21:26 AM PDT by montomike (Politics should be about service and not a lucrative, money-making opportunity!)
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To: BGHater
Wrong-O!

It was Dinosaur farts! I read it in a newspaper article.

4 posted on 04/07/2009 10:24:47 AM PDT by TexGuy (If it has the slimmest of chances of being considered sarcasm ... IT IS!)
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To: BGHater
Photobucket
5 posted on 04/07/2009 10:24:47 AM PDT by dragonblustar ("... and if you disagree with me, then you sir, are worse than Hitler!")
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To: GodGunsGuts

How do you explain this?


6 posted on 04/07/2009 10:25:29 AM PDT by DevNet (What's past is prologue)
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To: BGHater

“Mr. McGee, don’t make me angry. You wouldn’t like me when I’m angry.”

—The late great Bill Bixby.


7 posted on 04/07/2009 10:26:01 AM PDT by olivia3boys
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To: BGHater

Hmmm....guess I won’t worry about making the bed or doing the dishes.

(we’re doomed!)


8 posted on 04/07/2009 10:26:09 AM PDT by EggsAckley ("There's an Ethiopian in the fuel supply." W.C Fields)
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To: BGHater
A brilliant burst of gamma rays may have caused a mass extinction event on Earth 440 million years ago—and a similar celestial catastrophe could happen again, according to a new study.

It wasn't the gamma rays themselves - it was what they created....


9 posted on 04/07/2009 10:26:38 AM PDT by Alex Murphy (Presbyterians often forget that John Knox had been a Sunday bowler.)
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To: BGHater

“A brilliant burst of gamma rays may have caused a mass extinction event on Earth 440 million years ago—and a similar celestial catastrophe could happen again, according to a new study.”.....

Right now, I’m more worried about the earthly catastrophe of socialism in America causing a mass extinction!......


10 posted on 04/07/2009 10:29:18 AM PDT by AngelesCrestHighway
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To: BGHater; tx_eggman
"At other times there have been ice ages without mass extinctions," he said.

What is he saying? That the earth has cooled and warmed and cooled and warmed in the past? Is this not Goresphemy?
11 posted on 04/07/2009 10:29:45 AM PDT by SpinnerWebb (mankind are more disposed to suffer, while evils are sufferable, than to right themselves)
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To: BGHater

I’ve never heard such a line of bullsh** in my whole life.
These people just thrive on “what-if” doomsday sensationalism.


12 posted on 04/07/2009 10:29:55 AM PDT by BuffaloJack (To stand up for Capitalism is to hope Teleprompter Boy fails.)
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To: BGHater

GRB haPPens.


13 posted on 04/07/2009 10:32:55 AM PDT by NormsRevenge (Semper Fi ... Godspeed.)
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To: BGHater
and a similar celestial catastrophe could happen again, according to a new study.

Good.

14 posted on 04/07/2009 10:37:15 AM PDT by mbarker12474 (If thine enemy offend thee, give his childe a drum.)
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To: BGHater

Somebody phone Al Gore let him know mankind isn’t is as powerful as he thinks.


15 posted on 04/07/2009 10:39:06 AM PDT by Vaduz
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To: BGHater
Just ain't possible cause all right thin’ folks know the world is only 6000 years old. /sarcoff
16 posted on 04/07/2009 10:50:49 AM PDT by starlifter (Sapor Amo Pullus)
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To: montomike

I see a possible engineering problem.

Assuming you wanted to enclose the solar system out to 40 astronomical units, just beyond the semi-major axis of the former planet Pluto, that that would be a sphere with a radius of about 6,000,000,000 kilometers.

The area of the necessary lead sphere would be 4.52 x 10^18 square killometers.

A two meter thick lead shell of this radius would weigh about 2.13 x 10^24 tons.

While substantially less than the sun’s mass of 2 x 10^27 tons it is about equal to the combined mass of Jupiter and Saturn. The problem is, they’re not made out of lead and it could take some time to develop the technology to transmute their current elements into lead. The energy cost for this could also be prohibitive.

There is also the problem in that lead doesn’t have the strength to support a hollow spiracle shape of that radius at that thickness.

You might want to consider something like neutronium. In fact, I’d like to propose an alternative solution. Why not build a ring of neutronium, or some similar material, with walls high enough to contain an atmosphere and rotate it with the sun at the center? At least that way part of the population would always be shielded in the event of a GRB at any given time and you could avoid mass extinctions. Has anyone thought of this?

:o)


17 posted on 04/07/2009 11:03:51 AM PDT by InABunkerUnderSF (Be There >>> http://www.secondamendmentmarch.com)
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To: BGHater

“mud-scurrying bottom dwellers”...Obama et al


18 posted on 04/07/2009 11:10:45 AM PDT by Stormdog (A rifle transforms one from subject to Citizen)
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To: InABunkerUnderSF

“If we can put a man on the moon, we can encase the solar system in lead!”

“Yes we can!” “Yes we can!”


19 posted on 04/07/2009 11:18:15 AM PDT by LRS (Just contracts; just laws; just a constitution...)
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To: BuffaloJack

Actually, the sensationalism is about what was rather than wht might be. The dooms day actually happened.


20 posted on 04/07/2009 3:28:14 PM PDT by bert (K.E. N.P. +12 . John Galt hell !...... where is Francisco dÂ’Anconia)
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To: InABunkerUnderSF

Sounds like you have spent way, way too much time in the bunker with a copy of Excel.

I was just thinking of the Dyson Sphere episode of Star Trek Next Generation where they pull Scotty out of the transporter infinite loop and he rescues them by figuring out the Dyson Sphere around a solar system.


21 posted on 04/07/2009 5:56:43 PM PDT by montomike (Politics should be about service and not a lucrative, money-making opportunity!)
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The Cycle of Cosmic Catastrophes: Flood, Fire, and Famine in the History of Civilization The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization

by Richard Firestone,
Allen West, and
Simon Warwick-Smith


22 posted on 04/07/2009 6:59:19 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/____________________ Profile updated Monday, January 12, 2009)
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To: BGHater; 75thOVI; aimhigh; Alice in Wonderland; AndrewC; aragorn; aristotleman; Avoiding_Sulla; ...
Thanks BGHater.
 
Catastrophism
 
· join · view topics · view or post blog · bookmark · post new topic ·

23 posted on 04/07/2009 6:59:35 PM PDT by SunkenCiv (https://secure.freerepublic.com/donate/____________________ Profile updated Monday, January 12, 2009)
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To: montomike

Actually, I just used the Windows scientific calculator.

This is the sort of thing happens when business gets so slow that I have time to freep in the middle of the day. I wish Obama would stop trying to “save” the economy. My clients are afraid to spend money.


24 posted on 04/07/2009 7:02:11 PM PDT by InABunkerUnderSF (Be There >>> http://www.secondamendmentmarch.com)
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To: SunkenCiv
As I remember the guesses now are that this was the second worst mass extinction, not as bad as the Permian/Triassic extinction which led to the age of the Dinosaurs, but worse than the most famous mass extinction, the Cretaceous/Tertiary one that wiped out the Dinosaurs. Harder to prove, since there were no land animals to speak of in the Ordovician.

There was a later mass extinction in the Tertiary in which the dominant primitive mammals and giant birds lost out to the more modern types of mammals (except in South America and Australia where they held out much longer, even to the modern period.

25 posted on 04/08/2009 6:02:09 AM PDT by Lucius Cornelius Sulla ("men of intemperate minds cannot be free. Their passions forge their fetters." -- Edmund Burke)
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