Nemesis - the death star - possibly revealed.

[Jura <pristichampsus@yahoo.com>]

For the most part the old hypothesis about a possible
sister sun (white dwarf, whatever), with a huge orbit,
has since been shown to be likely false. Now new
evidence on the near cyclical nature of Earth's
extinctions has come to light.

Nemesis has been found!

Nemesis is ...

OUR SUN! (*Bum* *Bum* *Bum*)

Bad Astronomer Phil Plait goes into detail on new
findings which suggest that the sun's wobbly orbit
through the Milky Way may have been a possible trigger
for extinction events on Earth.

Full story can be read here:

http://www.badastronomy.com/bablog/2008/05/06/bobbing-for-extinctions/

Some highlights:

________________________________

In my research, I came across the idea that when the
Sun is at the apex of its bobbing, towards galactic
north, it?s about 100 light years above the galactic
plane. That?s far enough up that the magnetic fields
of the galaxy are weaker, and it?s these fields that
protect the Sun (and the planets, meaning us) from
intergalactic cosmic rays, subatomic particles that
zip around space between galaxies. When the Sun is up
high, these cosmic rays can strike us, and we have to
endure this particulate rain for millions of years.
The radiation can do bad things, like damage the ozone
layer or induce genetic mutations.

...

A new result has just been announced that says that
when the Sun is in the thick of the Milky Way?s plane,
tides from the galaxy can induce comets from the outer
solar system to plunge down toward the Sun, meaning
many will hit the Earth and potentially cause mass
extinctions.

...

According to the new study, this happens every 35 - 40
million years, which is not too far off from the
calculations in the older study. Since the Sun moves
up and down in the plane, it actually plunges through
the mid-plane twice each cycle. If it reaches its apex
every 64 million years, then it should pass through
the mid-plane every 32 million years, which is
reasonably close to what the second study says.

_________________________________________


Jason


"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer


      
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