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RE: " we're evolved for radiation " - geophysicist on pole revers als
Jaro,
Thanks for putting a "date" on the last magnetic field reversal. I always
assumed that the atmosphere was the source of shielding for life on earth..
That is why any life on Mars would be primitive at best, and why single cell
creatures were the only life form on Earth for so long..
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
E-mail: jenday1@email.msn.com (H)
-----Original Message-----
From: Franta, Jaroslav [mailto:frantaj@AECL.CA]
Sent: Monday, November 04, 2002 10:11 AM
To: 'John Jacobus'; RADSAFE
Subject: RE: " we're evolved for radiation " - geophysicist on pole revers
als
-----Original Message-----
From: John Jacobus [mailto:jenday1@MSN.COM]
Sent: Sunday November 03, 2002 9:00 PM
To: RADSAFE
Subject: Re: " we're evolved for radiation " - geophysicist on pole
reversals
Jaro,
What is meant by "we're evolved for radiation?" Had humans evolved the last
time it occurred, or was life more primitive?
-- John
Yes, humans were around the last time we had a polarity flip, 780,000 years
ago.
But that's besides the point.
Many human environmental adaptations seem to go way back to our primitive
ancestral forms, possibly as far back as single-celled organisms (that
appears to be the gist of the papers I've read, such as those by Andrew
Karam).
All in all, there have been about 1,000 polarity reversals, which are
recorded in the earth's crust like magnetic tape (earliest ones in the old
crust near subduction zones, latest ones at the mid-oceanic rift zones).
During the vast majority of those, only single-celled life existed on the
earth.
Jaro
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