Freethought & Rationalism Archive

Dr.GH · 06-06-2003, 08:11 PM

There are a number of critical responces to the research on the 3.8 to 3.9 Ga life. Examples:

Pro:

Mojzsis, Stephen J., T. Mark Harrison,
2000 �Vestiges of a Beginning: Clues to the Emergent Biosphere Recorded in the Oldest Known Sedimentary Rocks� GSA Today, April

Con:

VAN ZUILEN, MARK A., AIVO LEPLAND & GUSTAF ARRHENIUS
2002 Reassessing the evidence for the earliest traces of life Nature Vol 418: 6898 627-630

Kerr, Richard A.
2002 �Reversal Reveal Pitfalls in Spotting Ancient and E.T. Life� Science (Perspectives) 296:1384-1385

Joe Meert · 06-06-2003, 08:44 PM

Quote:

Originally posted by Coragyps
From the Science article itself:
Stein B. Jacobsen
Science vol 300, Jun 6 2003: 1513-1514.

W means tungsten - tungsten 182, the isotope used for the studies reported here, in this context. So yes, he has strongly suggestive evidence, but Jacobsen himself doesn't think that the last word is said yet on exactly when and how our planet accreted.

JM: I must say that my own opinion is that the errors associated with the method are wider than the assertion made by Jacobsen. Nevertheless (as others have pointed out), it still does not come close to 6000 years. In addition, it depends somewhat on how one defines 'earth'. Is 60% enough? If we consider solely the initial clumping of matter to constitute the proto-earth, then we can push back the formation closer to 5 billion. I hate to trivialize the article, but to me this was no big deal.

Cheers

Joe Meert

thebeave · 06-06-2003, 09:41 PM

Isn't the earth 4.6 billion and 23 years old? When I took geology in college 23 years ago, my prof said the earth was 4.6 billion years old.

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06-06-2003, 08:11 PM	#11
Dr.GH Veteran Member Join Date: Jul 2001 Location: Dana Point, Ca, USA Posts: 2,115	There are a number of critical responces to the research on the 3.8 to 3.9 Ga life. Examples: Pro: Mojzsis, Stephen J., T. Mark Harrison, 2000 �Vestiges of a Beginning: Clues to the Emergent Biosphere Recorded in the Oldest Known Sedimentary Rocks� GSA Today, April Con: VAN ZUILEN, MARK A., AIVO LEPLAND & GUSTAF ARRHENIUS 2002 Reassessing the evidence for the earliest traces of life Nature Vol 418: 6898 627-630 Kerr, Richard A. 2002 �Reversal Reveal Pitfalls in Spotting Ancient and E.T. Life� Science (Perspectives) 296:1384-1385

06-06-2003, 09:41 PM	#13
thebeave Veteran Member Join Date: Dec 2001 Location: Silicon Valley, CA Posts: 4,183	Isn't the earth 4.6 billion and 23 years old? When I took geology in college 23 years ago, my prof said the earth was 4.6 billion years old.

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