Posted on 05/02/2008 8:53:50 AM PDT by blam
Sun's Movement Through Milky Way Regularly Sends Comets Hurtling, Coinciding With Mass Life Extinctions
A large body of scientific evidence now exists that support the hypothesis that a major asteroid or comet impact occurred in the Caribbean region at the boundary of the Cretaceous and Tertiary periods in Earth's geologic history. Such an impact is suspected to be responsible for the mass extinction of many floral and faunal species, including the large dinosaurs, that marked the end of the Cretaceous period. (Credit: Art by Don Davis / Courtesy of NASA)
ScienceDaily (May 2, 2008) — The sun's movement through the Milky Way regularly sends comets hurtling into the inner solar system -- coinciding with mass life extinctions on earth, a new study claims. The study suggests a link between comet bombardment and the movement through the galaxy.
Scientists at the Cardiff Centre for Astrobiology built a computer model of our solar system's movement and found that it "bounces" up and down through the plane of the galaxy. As we pass through the densest part of the plane, gravitational forces from the surrounding giant gas and dust clouds dislodge comets from their paths. The comets plunge into the solar system, some of them colliding with the earth.
The Cardiff team found that we pass through the galactic plane every 35 to 40 million years, increasing the chances of a comet collision tenfold. Evidence from craters on Earth also suggests we suffer more collisions approximately 36 million years. Professor William Napier, of the Cardiff Centre for Astrobiology, said: "It's a beautiful match between what we see on the ground and what is expected from the galactic record."
The periods of comet bombardment also coincide with mass extinctions, such as that of the dinosaurs 65 million years ago. Our present position in the galaxy suggests we are now very close to another such period.
While the "bounce" effect may have been bad news for dinosaurs, it may also have helped life to spread. The scientists suggest the impact may have thrown debris containing micro-organisms out into space and across the universe.
Centre director Professor Chandra Wickramasinghe said: "This is a seminal paper which places the comet-life interaction on a firm basis, and shows a mechanism by which life can be dispersed on a galactic scale."
The paper, by Professor Napier and Dr Janaki Wickramasinghe, is to be published in the Monthly Notices of the Royal Astronomical Society.
Adapted from materials provided by Cardiff University, via EurekAlert!, a service of AAAS.
Comet/Asteroid Impacts
and Human Society
ed by Peter T. Bobrowsky
and Hans Rickman
intro (PDF)
due to links here
“And how is a rotating earth simpler?”
It requires no special explanation for all the other rotating bodies that we observe, in other words a difference between them and the Earth. Obviously the Universe can’t be rotating around all of them, they spin on different axes. ;-)
I’ve been in a mass bombardment and I can tell you it’s no fun.
That’s nice. Science is an illusion.
Everything is illusion.
OK, so how is assuming that there is no difference between the earth and rotating bodies we observe less an assumption than assuming that there is a difference between the earth and the rotating bodies we observe and therefore an argument for Occam's Razor?
What about objects that aren't observed to rotate, like the moon. You assume they do rotate even though they appear not to? Where is Occam's Razor now?
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Thanks Blam. To all -- this topic is getting a little ugly, but I have posted a droll joke, so... |
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It's a wonder that we aren't thrown into outer space....
I prefer that old proverb (or perhaps ko’an) from India, “the universe is the dream of the Gods, and the Gods are the dream of man.” ;’)
Who knew Bill even *had* a cell phone? :’)
Heh - party like it’s 2011 - pretty funny!
I’m disappointed. 32 posts and Laz has not declared we are all going to die.
I knew it. I juuuuust knew it... sigh
Scientists at the Cardiff Centre for Astrobiology built a computer model of our solar system's movement and found that it "bounces" up and down through the plane of the galaxy. As we pass through the densest part of the plane, gravitational forces from the surrounding giant gas and dust clouds dislodge comets from their paths. The comets plunge into the solar system, some of them colliding with the earth. The Cardiff team found that we pass through the galactic plane every 35 to 40 million years, increasing the chances of a comet collision tenfold.[note: this is the same idea advocated by the late Gene Shoemaker; also, this stands as an alternative to the Nemesis model for periodicity in the impact record]
Breathe deep the gathering gloom,
Watch lights fade from every room.
Bedsitter people look back and lament,
Another day’s useless energy spent.
Impassioned lovers wrestle as one,
Lonely man cries for love and has none.
New mother picks up and suckles her son,
Senior citizens wish they were young.
Cold hearted orb that rules the night,
Removes the colours from our sight.
Red is gray and yellow white,
But we decide which is right.
And which is an illusion?
Nemesis: Does the Sun Have a ‘Companion’?
SPACE dot COM | 03 April 2001 | By Robert Roy Britt
Posted on 02/10/2003 11:03:23 AM PST by vannrox
http://www.freerepublic.com/focus/f-news/839980/posts
Could An Asteroid Hit Planet Earth, Again?
Science Daily | 1-20-2008 | Planetary Society
Posted on 01/30/2008 3:46:10 PM PST by blam
http://www.freerepublic.com/focus/f-news/1962278/posts
Earth-sized planet predicted beyond Pluto
Cosmos Magazine | Friday, February 29, 2008 | Agence France-Presse
Posted on 03/20/2008 11:43:43 PM PDT by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1989253/posts
But the moon does rotate. It’s that it’s rotation is geosynchronous with the earth. If it didn’t we’d see its other side.
“sit on it and rotate, Potsie” ?
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