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The rise and fall of species on Earth might be driven in part by the undulating motions of our solar system as it travels through the disk of the Milky Way, scientists say.

Two years ago, scientists at the University of California, Berkeley found the marine fossil record shows that biodiversity—the number of different species alive on the planet—increases and decreases on a 62-million-year cycle. At least two of the Earths great mass extinctions—the Permian extinction 250 million years ago and the Ordovician extinction about 450 million years ago correspond with peaks of this cycle, which cant be explained by evolutionary theory.

Their idea hinges upon the fact that, appearances aside, stars are not fixed in space.

In particular, our Sun moves toward and away from the Milky Ways center, and also up and down through the galactic plane. One complete up-and-down cycle takes 64 million years— suspiciously similar to Earths biodiversity cycle.

The galactic bow shock is only present on the north side of the Milky Way’s galactic plane, because that is the side facing the Virgo Cluster as it moves through space, and it would cause superheated gas and cosmic rays to stream behind it, the researchers say. Normally, our galaxys magnetic field shields our solar system from this “galactic wind.” But every 64 million years, the solar systems cyclical travels take it above the galactic plane.

'When we emerge out of the disk, we have less protection, so we become exposed to many more cosmic rays,' Melott told SPACE.com.

The boost in cosmic ray exposure could have both a direct and indirect effect on Earths organisms, said KU paleontologist Bruce Lieberman. The radiation could lead to higher rates of genetic mutations in organisms or interfere with their ability to repair DNA damage, potentially leading to diseases like cancer.

'I think its a very nice idea,' said Philip Appleton, a Caltech astronomer. 'I think were only beginning to come to grips with these kinds of behaviors. We’re realizing that not only do galaxies interact with each other gravitationally, but also that the environment they re traveling through the 'wind' they create can actually produce noticeable effects.'

Full Article Here

http://www.space.com/scienceastronomy/070423_cosmic_evo.html

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"You will never find a real Human being - even in a mirror." .....Mike Kremer.
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"You will never find a real Human being - Even in a mirror." ....Mike Kremer.


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Well, Mike, we seem to share a common interest. I posted this in the General Science forum a few days ago: "Galaxy bow shock and biodiversity cycle"

A different link, though:

http://www.lbl.gov/Science-Articles/Archive/Phys-fossil-biodiversity.html

I think it's tremendously interesting. About 25 years ago there was a theory of mass extinctions based on this movement of the Solar System through the galactic plane. That seems to have bitten the dust, but the biodiversity correlation in very convincing.



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Mike. I read Rede's post a few days ago but, to get a different view I looked at your link. Basically a blank page. Lovely shade of green though. What's happened?

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Hmmmm, sounds as tho' you just got the green/blue background.

I dont think it uses "Quicktime"
But cut-down the URL to its basic ie. http://www.space.com/
...and go for the Science, tab first.

Mike Kremer.

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I've clicked on Mike's post and found the article in question. Maybe your browser was having a bad hair day.


If you don't care for reality, just wait a while; another will be along shortly. --A Rose

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Originally Posted By: terrytnewzealand
Mike. I read Rede's post a few days ago but, to get a different view I looked at your link. Basically a blank page. Lovely shade of green though. What's happened?

As Amaranth said...must be me having a bad hair day, my browser slipped up?
I posted a possible answer in my second posting.
Wont post here again Redwenur, has done a great job elsewhere

Mike Kremer.

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Thanks all. While flicking through I found this:

http://www.livescience.com/forcesofnature/070426_petm_volcano.html

I'll put it on climate change.

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Mike: "Wont post here again Redwenur, has done a great job elsewhere"

- you're an honourable man, as ever grin


"Time is what prevents everything from happening at once" - John Wheeler

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