It hasn't had much impact. Assuming that the Earth has accumulated 50,000
tons per year, every year for 4.5 billion years, the accumulated mass is
less than a billionth of the Earth's total mass.
BTW, I don't think we've lost much oxygen to outgassing. Oxygen is highly
reactive, and its concentration in the atmosphere depends on a combination
of biological and geological processes. It can be reduced (volumetrically,
not chemically!) in the atmosphere without being lost to space.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
----- Original Message -----
From: "E.P. Grondine" <epgrond...@yahoo.com>
To: <meteorite-list@meteoritecentral.com>
Sent: Tuesday, January 26, 2010 3:59 PM
Subject: [meteorite-list] Dust, and millions and millions of years
Hi all -
"...approximately 40,000-60,000 t of extraterrestrial material
lands on Earth every year, the majority of which is in the form of tiny
dust grains usually less than 1 mm (1/25 in) in size; importantly, most
of this dust is believed to originate from comets..."
So how massive was the Earth at formation, when the insects ruled, when
the reptiles ruled, when the dinosaurs ruled? What percentage of current
gravity during each period?
We know that when insects ruled, the Earth's atmosphere had far more
oxygen, apparently later out-gassed to space.
I wonder what the long term future holds? Some quick math, Sterling,
anyone?
Ed "E.P."
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