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-Short Attention Span Theater-
Mass extinction comes every 62 million years, UC physicists discover
2005-03-11
With surprising and mysterious regularity, life on Earth has flourished and vanished in cycles of mass extinction every 62 million years, say two UC Berkeley scientists who discovered the pattern after a painstaking computer study of fossil records going back for more than 500 million years.

Their findings are certain to generate a renewed burst of speculation among scientists who study the history and evolution of life. Each period of abundant life and each mass extinction has itself covered at least a few million years -- and the trend of biodiversity has been rising steadily ever since the last mass extinction, when dinosaurs and millions of other life forms went extinct about 65 million years ago.

The Berkeley researchers are physicists, not biologists or geologists or paleontologists, but they have analyzed the most exhaustive compendium of fossil records that exists -- data that cover the first and last known appearances of no fewer than 36,380 separate marine genera, including millions of species that once thrived in the world's seas, later virtually disappeared, and in many cases returned.
Posted by:Sobiesky

#20  TW, contrary to preconceived notions about Eastern Europeans, I just can't stand the Little Water.
It wuz him 3dc, I swear! ;-)
Posted by: Sobiesky   2005-03-11 11:53:58 PM  

#19  Sobiesky, you've mixed them up again: drinking the Little Water causes the headache. Drinking a little water to wash down the aspirin is what makes the headache go away ;-D
Posted by: trailing wife   2005-03-11 11:34:57 PM  

#18  3dc, I have a feeling that your 2 questions are inherently ... flawed. Could you please rephrase?

For instance, I have a hard time to accept that we invented multicellular life. If you can prove that one, then "using up all the frozen natural gas deposits just before" may have some merit.

"And this came out just now to save us from using those huge deposits that might be posible to mine"

What on earth you are trying to say?

Darn! You caused me a serious splitting headache now!

Going to take some aspirin... and get horizontal... breath in, breath out...
Posted by: Sobiesky   2005-03-11 8:03:57 PM  

#17  Ice Age, gromgorru? It still is, last 2my. But then there are more icey ages within Ice Age. The last icey age (glacial) kicked in about 70k BCE and ended about 12.5K BCE. Since then we have interglacial (less icey age).
Posted by: Sobiesky   2005-03-11 7:51:51 PM  

#16  When we last used up all the frozen natural gas deposits on the seafloor just before inventing multicellular life?

And this came out just now to save us from using those huge deposits that might be posible to mine in Alaska, Canada and the Golf of Mexico?
Posted by: 3dc   2005-03-11 7:49:14 PM  

#15  3 skunks talking: Poppa Skunk, "My instinct tells me it's gonna rain". Momma Skunk, "My instinct tells me it's gonna snow". Baby Skunk, "My end stinks too, but it doesn't tell me anything."
Posted by: Deacon Blues   2005-03-11 7:47:35 PM  

#14  When was the last one? Exactly.
Posted by: gromgorru   2005-03-11 7:42:30 PM  

#13  Phil, yea so its kinda hard to prove.. I can imagine that as the whole earth clima got colder that there were some seasonal/nocturnal ice formations in current tropical regions. But that doesn't mean the earth was a frozen icicle in toto.
Posted by: Sobiesky   2005-03-11 5:45:49 PM  

#12  One thing the article doesn't go into but is key is that once the oceans are covered in ice, precipitation stops and hence no sedimentary rocks where we look for fossils are formed. There will be a discontinuity in the geological record but no evidence of what happened, so its kinda hard to prove.
Posted by: phil_b   2005-03-11 5:39:07 PM  

#11  The discovery of this theory is a classic scientific detective story. For decades there had been a growing 'X-File' of geological anomalies haunting the scientific community. Telltale signs of past glaciation have been found in places that should have been much too hot - very near the equator. Even during the most severe ice age, scientists believed that the ice only reached as far down as Northern Europe and the middle of the USA. So what could these tropical deposits mean? Snowball earth
Posted by: phil_b   2005-03-11 5:17:17 PM  

#10  Phil, There is evidence...

Where?
Posted by: Sobiesky   2005-03-11 4:40:27 PM  

#9  There is evidence that ice ages rather than covering the earth up to the midlattitudes, cover the whole earth. Runaway cooling results in earth completely covered in ice and a mass extinction. This is stable until large scale volcanic activity breaks us out of the cold phase. Something similar may happen on Mars.
Posted by: phil_b   2005-03-11 4:05:56 PM  

#8  One last thing, I believe the current state of "conventional wisdom" is that there isn't enough dark matter to make the rubber band theory work - and the universe will continue expanding infinitely with the distance between the galaxies increasing infinitely. So someday, we will only have the Milky Way to play with, sniff, sniff. Of course, if the string theory guys are right, and I get the gist correctly, someday our "plane" will collide with another "plane" in the 11th dimension and we'll see some serious Big Bang style fireworks. Again.
Posted by: .com   2005-03-11 12:09:53 PM  

#7  Heh, I think all the details you require are contained in the Universe Song from Python's Meaning of Life... Enjoy!
Posted by: .com   2005-03-11 12:02:28 PM  

#6  Well. That's it then. It was nice knowing you all. Catch you on the flip side...
Posted by: Seafarious   2005-03-11 12:02:15 PM  

#5  or about every 62 million years on our ride around the galaxy, the Oort cloud is disrupted and sends greetings towards the inner orbital ring of the solar system.

JD:... Even at this blazing speed, it takes the sun about 200 million years to complete one journey around the galaxy's core.

DB: The orbital speed of a star around the center of our galaxy depends on its distance from the center. A star's orbital speed can be predicted from the galaxy's mass, and the star's location. But something mysterious is taking place at distances in the galaxy beyond the orbit of our sun. The speed of these outermost objects doesn't decrease as much as expected.

JB: So astronomers think there may be a large amount of undetected mass around our galaxy -- part of the unseen, dark matter of the universe.

Yep, just fine, like driving in bad weather conditions, even with your lights on, you can't see too far ahead of you. So we have speed bumps about every 62 million years. Or are we the deer in the headlights?
Posted by: Angash Spinelet3775   2005-03-11 11:53:31 AM  

#4  If you're really serious about doom and gloom.
Posted by: Shipman   2005-03-11 11:49:23 AM  

#3  So....eating lots of fiber, maintaining a veggy diet, working 3 hours a day at the gym is for naught? They promised me immortality, the damn con artists!
Posted by: Glereper Thigum7229   2005-03-11 9:42:35 AM  

#2  62 million years is the time limit on the demo version of SimEarth. I'm not springing for the commercial version.
Posted by: Gawd   2005-03-11 9:12:38 AM  

#1  I read a different version on these two guys at:
http://news.nationalgeographic.com/news/2005/03/0309_050309_extinctions.html

Here are a few choice excerpts that are left out of the version above:

"The pattern includes a rise and fall of marine animal diversity every 62 million years and a weaker cycle of rising and falling marine diversity, which repeats every 140 million years. The researchers think that expanding and retreating glaciers may explain the 140-million-year cycle..."

"Muller went so far as to purchase a lava lamp, plug it in, and studiously gaze at how often the blobs rose to the surface. He thought perhaps magma bubbles from the Earth's core rise in a cyclical pattern."

"We took all the best data and put it with the best timescale..."

"Perhaps the periodicity did not strike my eye because so many previous analyses on regularities in extinctions and diversity have proved erroneous in the past."

"Kiessling said the pattern most likely stems from fluctuations in the fossil record caused by fluctuations in sea level. The number and abundance of fossils preserved on the seafloor is less when sea levels are low, he explained."

"Alroy added that the observed cyclical patterns could simply be the result of an error in the statistical analysis."
Posted by: Tom   2005-03-11 8:34:10 AM  

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