[meteorite-list] Look on the Moon for the first evidence of life on Earth?

From: Aubrey Whymark <tinbider_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:10 2004
Message-ID: <20040128193021.15561.qmail_at_web25205.mail.ukl.yahoo.com>

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>From a previous email:
"Our research shows the structures found in the NASA meteorite were more than likely made by bacteria present on Mars four billion years ago - before life even started on Earth."

Discussion:

We don't have the rocks on Earth to accurately say when life started because of recycling due to plate tectonics. The oldest rock is 4.03 Ga old. The ancient rocks we are left with have been through a lot and are often highly metamorphosed. See the following link for ages of the oldest Earth rock: http://pubs.usgs.gov/gip/geotime/age.html

The oldest bacterial fossils on Earth are 3.5 billion years old but probably originated before that. The rocks are often so metamorphosed that any fossil traces will be destroyed. The isotope ratios between Carbon-12 and Carbon-13, however, indicate life was present as much as 3.85Ga ago (although this has been questioned). Then, tiny zircon crystals reworked into younger rocks, but dating back to 4.3Ga to 4.4Ga, suggest possibilities life may be even older. They indicate the possibility of oceans and environments in which microbial life could emerge - 4.3 billion to 4.4 billion years ago.

As the ancient rocks on Earth are either not available due to plate tectonics or highly metamorphosed it has been suggested that the best place to look for life on Earth may be on the moon. Ancient terrestrial rock would have made it to the moon relatively unaltered. See the following very interesting article.

http://www.nature.com/nsu/021028/021028-13.html

Aubrey





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<DIV>
<DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">
<P>From a previous email:<BR>"Our research shows the structures found in the NASA meteorite were more than likely made by bacteria present on Mars four billion years ago - before life even started on Earth."</P>
<P>Discussion:</P>
<P>We don't have the rocks on Earth to accurately say when life started because of recycling due to plate tectonics.&nbsp; The oldest rock is 4.03 Ga old.&nbsp; The ancient rocks we are left with have been through a lot and are often highly metamorphosed.&nbsp; See the following link for ages of the oldest Earth rock: <A href="http://pubs.usgs.gov/gip/geotime/age.html">http://pubs.usgs.gov/gip/geotime/age.html</A></P>
<P>The oldest&nbsp;bacterial fossils on Earth&nbsp;are 3.5 billion years old but probably originated before that.&nbsp; The rocks are often so metamorphosed that any fossil traces will be destroyed.&nbsp; The isotope ratios between Carbon-12 and Carbon-13, however,&nbsp;indicate life was present as much as 3.85Ga ago (although this has been questioned).&nbsp; Then, tiny zircon crystals&nbsp;reworked into younger rocks, but dating back to 4.3Ga to 4.4Ga, suggest possibilities life may be even older.&nbsp; They indicate the possibility of oceans and environments in which microbial life could emerge - 4.3 billion to 4.4 billion years ago.</P>
<P>As the ancient rocks on Earth&nbsp;are either not available due to plate tectonics or highly metamorphosed it has been suggested that the best place to look for life on Earth may be on the moon.&nbsp; Ancient terrestrial rock would have made it to the moon relatively unaltered.&nbsp; See the following very interesting article.</P>
<P><A href="http://www.nature.com/nsu/021028/021028-13.html">http://www.nature.com/nsu/021028/021028-13.html</A></P>
<P>Aubrey<BR></P></BLOCKQUOTE></DIV></DIV><p><hr size=1><font face="Arial" size="2"><font size="2" face="Arial, Helvetica, sans-serif">BT
Yahoo! Broadband - Free modem offer, <a href="http://uk.rd.yahoo.com/evt=21064/*http://btyahoo.yahoo.co.uk">sign up online</a> today and save £80</font>
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Received on Wed 28 Jan 2004 02:30:21 PM PST