[meteorite-list] Party for the oldest piece of earth?

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Sun Apr 10 12:23:37 2005
Message-ID: <42595282.7E092AFF_at_bhil.com>

Hi,

    Martin's right, of course. Technically, it's the oldest piece of the Earth yet discovered that was formed on the Earth, so it's the "oldest thing ever" only in the context of terrestrial geology. Every scientist sees everything only in their own context, you know.
    The Dawn Zircon demonstrates that 4.4 billion years ago, the Earth was not a raging inferno of molten rock that makes the Venus of today seem mild by comparison. Terrestrial geology has always believed that there was this initial prolonged and really nasty stage, which they have
dubbed the Hadean Era. Doesn't seem to be so.
    There had to be liquid water in great abundance, with reasonable temperatures, not boiling away, and continents with the usual geologic processes taking place for this zircon to form. Maybe not ready to build shopping plazas on, but surprisingly "earth-like."
    Meteorites are a trivial 4.56 billion years old. When compared to the 13.5 billion years the Universe has been around, hey! what's the big deal? Recent trash rocks, that's what. We love'em anyway.
    Someday (if we're real lucky) we'll find a meteorite that has an odd inclusion in it that, when we date it, turns out to 6.73 billion years old (or whatever), a piece of the pre-solar formation Universe. Maybe. As the comedienne Judy Tenuta says, "It could happen..."
    Wonderful as zeroing in closer and closer to the formation of the solar system is, it is only one more strictly local event, one of countless billions, and important to us only because we happen to be in it.
    The wonderful thing about Time is -- there's so much of it. The sad thing about Time is -- we get so little of it.

Sterling K. Webb
-------------------------------------------
martinh_at_isu.edu wrote:

> Hi All,
>
> If the museum director think this is the oldest thing ever, then he has missed most of the meteorites, and almost all of the universe.
>
> Hmmm, maybe someone could crash their party with a nice piece of Allende?
>
> -Martin
>
> http://www.cnn.com/2005/TECH/science/04/09/oldest.object.ap/index.html
>
> Earth's 'oldest thing ever' gets viewing
>
> Zircon crystal sample believed to date back 4.4 billion years
>
> Saturday, April 9, 2005 Posted: 9:58 PM EDT (0158 GMT)
>
> Discovered in Australia in 1984, this speck of zircon crystal is believed to be the oldest known piece of Earth.
>
> MADISON, Wisconsin (AP) -- Call it much ado about almost nothing.
>
> To create buzz about an otherwise arcane subject, the University of Wisconsin-Madison showed off a tiny speck of zircon crystal believed to be the oldest known piece of Earth at about 4.4 billion years old.

> "This is it -- the oldest thing ever. One day only," said Joe Skulan, director of the UW-Madison Geology Museum, where the object was displayed under police guard. "The idea of having a big celebration of something that's so tiny -- we're playing with the obvious absurdity of it."
>
> snip----------
Received on Sun 10 Apr 2005 12:21:22 PM PDT


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