Ferromagnetic materials retain a net magnetic moment after exposure to a
magnetic field. Paramagnetic materials do not, even though they are
similarly attracted to magnets. Both iron and nickel, the primary
constituents in magnetic meteorites, are highly ferromagnetic. However,
unless they have been exposed to a very strong field, the crystalline
nature of the material means that the magnetism is confined to many
small domains, which cancel each other out. So you don't see much
magnetism in meteorites at a macro scale. Not because the magnetism has
been lost, but because it probably never existed.
The interior of a meteorite never comes close to the curie temperature
of iron or nickel during entry. An meteorite will have the same magnetic
properties on the ground that it had in space (other than the outer
millimeter or so).
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
----- Original Message -----
From: "Peter A Shugar" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, December 03, 2007 9:59 AM
Subject: [meteorite-list] more data
Mike,
Consider this. When the meteorite or iron comes into the magnetic
field of
the magnet, it is attracted
to the magnet. This could be construed as the first stroke of the
piece on
the magnet. The piece needs to be stroked in the same direction a
number of
times to become a magnet, so with only the "one" stroke,
it would leave the piece very slightly magnetic !!
Magnetite is a naturally occurring mineral that is already magnetic.
It's
attracted to the magnet,and the orientation of the magnetite will be
such
that its polarity is the opposite of the pole on the magnet.
As to the 'slightly magnetic" meteorite, remember the above, it's the
first
"stroke".
Also, the heat of the entry into the atmosphere will kill any
magnetism of
the meteorite.
Lastly, the shock of the material being ejected from the parent body
will
also kill the magnetism.
This can be demonstrated by simply taking a magnet and bashing it very
,
very hard with a sledge hammer.
The one blow may not kill all the magnetism, but it surely will be a
weaker
magnet.
This causes the aligned molecules of the magnet to be scrambled, thus
destroying the magnet.
Naturally occurring magnetic meteorite----No.
Pete
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