Posted on 12/30/2003 2:29:48 PM PST by EUPHORIC
Scientists have new theory on ice age
KU researchers believe gamma-ray burst caused extinctions, cooling
By Alea Smith - Special to the Journal-World
Monday, December 29, 2003
Researchers now believe a cosmic explosion 440 million years ago may have decimated life on Earth.
Kansas University scientists are attracting international attention with their research into the possibility a massive gamma ray explosion caused an ice age that wiped out much of the life on Earth.
"It appears that the (gamma ray) bursts are a serious danger, although not something you would expect to hit us very often, maybe every few hundred million years," said Adrian Melott, a professor of physics and astronomy.
Melott and Bruce Lieberman, an associate professor of geology, are studying whether gamma ray bursts were responsible for high extinction rates in shallow-water marine species -- amoebas, sponges and coral-like creatures and some marine species with hard shells -- while other species survived.
The effects were worse on shallow-water species, the scientists believe, because deeper water protected other species.
"There is a variety of evidence for this particular time period," Lieberman said. "There is chemical evidence as well as the animals that made it through and those that go extinct."
Two international science magazines, New Scientist and Nature, have recently reported the KU researchers' hypothesis.
Others working on the theory since last spring have included Claude Laird, associate professor of physics and astronomy at KU; Mikhail Medvedev, assistant professor of physics and astronomy at KU; and officials from the NASA Goddard Space Flight Center in Greenbelt, Md.
Previous theories have attributed the extinction to the start of an ice age but offer no explanation as to what triggered the ice age during a relatively warm climate.
Gamma-ray bursts occur when a giant star explodes, creating a burst of nuclear energy in the form of gamma-rays, which have the smallest wavelength and most energy of all radiation.
The Earth's atmosphere would absorb the energy, which would separate nitrogen and oxygen molecules in the atmosphere, creating nitrogen oxides, including nitrogen dioxide, which plays a major role in the atmospheric reactions that produce ground-level ozone or smog.
The scientists' research has led them to believe the long-term effects of gamma-ray bursts would deplete the ozone and cause global cooling and acid rain. It would also increase the amount of direct ultraviolet rays from the sun, which only reach a depth of 10 meters in water. This explains why only shallow marine species were involved in the extinction.
The trilobite, an extinct hard-shelled marine creature, has been the focus of research so far. Its extinction pattern in the fossil record is similar to what scientists would expect to find with gamma-ray bursts. They are now looking further into other species that survived and died out during this time to find more connections.
Astronomers have observed and recorded many recent gamma-ray bursts from distant galaxies that have been harmless to the Earth.
"These bursts occurred more often when the solar system first formed," Lieberman said. "Ones like we think caused this extinction occur once every billion years or so, but that's just an estimate."
Melott said if a gamma-ray burst occurred within 10,000 light years on this side of the galaxy, the effects on Earth would be devastating.
"Anyone outside when this occurred would be blinded," Melott said. "The effects would be noticed right away."
Let me know if you wish to be added or removed from this list.
I don't get offended if you want to be removed.
The New York Times reports that women and minorities were severely impacted, while Tom Dascle was very concerned and deeply troubled,
Hear, hear.
I'd like to second that sentiment. When science looks stupid to an audience of layman, more often than not it's because the public reporting of it is garbled to the point of nonsense.
The second most common reason is because anyone with a lab coat can call himself a "scientist" and call a press conference to hear and report whatever wild notion he has, whether it's poorly grounded or not. Then the press dutifully reports, "Scientists say (or have found) that..."
It's important to remember that there's no "central science board" clearing and issuing such statements. Anyone can issue a press release about their latest "study", even if they've never managed to get any respected science journal to accept it for publication (or never even tried).
So how does "Science" with a capital "S" come about if there's no "central committee"? By the peer-review process -- people who have done new studies or come up with new hypotheses publish their work in one of the science journals, and after everyone else in the field has had a chance to check it out and critique it (ripping apart any that have obvious flaws, some of the review an be quite brutal), the work that survives the initial inspection and subsequent independent testing/verification gain acceptance by enough of the scientific community that it becomes part of the "body of knowledge" of science (even if there are always a few cranks who will inevitably dissent).
So in short, "Science" is that body of work which has gained widespread acceptance by the scientific community because it has been found to be solid. It's a matter of consensus.
So feel free to laugh at what any particular self-described "scientist" may say, but remember that it's often not the same as what "Science" as an institution holds or has accepted, and should be taken as no reflection on the institution's reliability.
Now back to your regular programing...
Best candidate for an Earth-fryer:
Eta Carinae is an *extremely* unstable supermassive star 8,000 light years from Earth. 150 years ago it flared up so strongly it reached energy outputs usually only seen in star-destroying supernova explosions (it became one of the brightest stars in the Earthly skies), producing the gigantic "barbell" shaped nebula seen in the photo above.
The cloud is so gigantic (4 *trillion* miles across) that one *pixel* in that image is about the size of our entire solar system. The cloud is expanding at 1.5 million miles per hour. The star itself is that white glow in the middle.
Eta Carinae is one of the most massive stars in our galaxy, and when it eventually lets loose and explodes it it is expected to temporarily outshine the rest of our galaxy combined, and may release enough gamma-ray energy to cause serious (or fatal) problems here on Earth.
And it's so unstable that astronomers have no way of knowing when it might finally "go off" -- every year it undergoes unpredictable fluctuations that might be precursors to the "big one". Note how much it has fluctuated in just this past year:
Radio emissions movie over the past 10 years:
Its final explosion could come at any time. It's always on the edge of going critical.
Sleep well.
Right next to the moose that bit my sister . . . . . .
That will certainly ruin my day!
Actually you are just not a comprehensive reader.
Article FULLY explains how this could cause an ice age.
Straight up.
INDEED! What we are seeing is probably the "cracker blast" and the front of radiation is most likely on the way right now.
Takes longer for most gamma and other fun things to travel then photons.
Interesting take on EMR.
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