Hello list members,
see the following link,
http://www.aanda.org/index.php?option=com_contenttask=viewid=181Itemid=42lang=en
where you can download the PDF file of the AA letter.
Katsuhito O.
Tokyo, JAPAN
- Original Message -
From: Rob McCafferty [EMAIL PROTECTED]
To: meteorite-list@meteoritecentral.com
Sent: Thursday, September 28, 2006 7:00 AM
Subject: [meteorite-list] Meteorites Used To Study Solar Activity AT LAST!!!
Hi all
This phenomena of cosmic ray alteration of isotope
concentration has been known to me for a long while.
As solar activity increases, it deflects the cosmic
rays which reduces the effect of cosmic rays.
On earth, one of it's best effects is altering the
amount of Carbon 14 (C14) prodced during periods of
high solar activity. C14 has a known half-life of
approx 5800 years and is created constantly so all
things once living have a known amount of it. Once
they die, this proportion decreases.
Less well known is that year on year, the proportion
of C12/C14 changes according to solar activity.
Correction factors have to be made in carbon dating.
Individual tree rings can be measured for actual vs
predicted C12/C14 ratios and a picture of solar
activity can be build up.
This method shows several things
Tree rings from 1640 to 1710 show a big increase in
C14 vs predicted signifying a low solar activity. This
roughly corresponds to a period of low temperature.
The Thames in London used to freeze each winter and
was so thick fairs could be held on the ice.
It suggests that in Roman times, temperatures were
even warmer than today. Grapes can only be grown in
south east England today. Back then they could be
grown North of York.
It also suggests a general increase in solar activity
over the last few hundred years, since the Maunder
minimum, in fact. We're on a rise now, apparently.
If meteorites are also showing this trend, some
credence must be give to the The Human Race is a
bunch of arrogant idiots who think they are more
influential in the Grand Scheme of Things than they
really are school of thought which I aspire to
ascribe.
Equally, I suggest that this blip in the epochs of
time should be a timely reminder not to mess with
things too much as we really have no idea how much
influence we really have.
Just my thoughts for the subject.
(DISCLAIMER: this post was not sponsored by
Shell/BP/XXon/FINA/Texaco or any other petrolium
industry, etc. The author cannot discount the
possibility that the original meteorite study may have
been. He would like to distance himself from any
suggestions to that effect
I think that puts me in the clear)
Anon (just in case)
--- Matson, Robert [EMAIL PROTECTED] wrote:
Hi All,
Who'da thunk that global warming could become an
on-topic
subject for the meteorite list?! --Rob
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
On Behalf Of Ron
Baalke
Sent: Tuesday, September 26, 2006 2:15 PM
To: Meteorite Mailing List
Subject: [meteorite-list] Meteorites Used To Study
Solar Activity
http://www.upi.com/NewsTrack/view.php?StoryID=20060926-015940-3936r
Meteorites used to study solar activity
UPI
September 26, 2006
OULU, Finland (UPI) -- A Finnish-led international
team has used
meteorites to investigate the sun's solar activity
of past centuries.
Ilya Usoskin at Finland's Sodankyla Geophysical
Observatory and
colleagues compared the amount of Titanium 44 in 19
meteorites that have
fallen to the Earth the past 240 years. They said
their findings confirm
that solar activity increased strongly during the
20th century. They
also find the sun has been particularly active
during the past few
decades.
The scientists say studying the sun's activity is
one of the oldest
astrophysical projects, as astronomers began
recording the number of
sunspots to trace the sun's magnetic activity 400
years ago.
The team examined a set of 19 meteorites whose dates
of fall are
precisely known, measuring the amount of radioactive
isotope Titanium 44
in each meteorite. Titanium 44 is produced by the
cosmic rays in the
meteorites while they are outside the Earth's
atmosphere. After the
meteorite has fallen, it stops producing the
isotope.
By measuring the Titanium 44 in the meteorites, the
scientists
determined the level of solar activity at the time
the meteorite fell.
The study appears in the journal Astronomy
Astrophysics Letters.
__
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
__
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
__
Meteorite-list mailing list
Meteorite-list
