In Physics, it would be 496. -----Original Message----- From: math-fun-bounces@mailman.xmission.com [mailto:math-fun-bounces@mailman.xmission.com] On Behalf Of Fred lunnon Sent: Tuesday, May 21, 2013 4:03 PM To: math-fun Subject: [EXTERNAL] Re: [math-fun] Younger Dryas Impact Hypothesis 28 authors --- is this the perfect number? WFL On 5/21/13, Hans Havermann <gladhobo@teksavvy.com> wrote:
The on-again, off-again Younger Dryas impact hypothesis is on again:
http://www.pnas.org/content/early/2013/05/17/1301760110
On Dec 5, 2012, I wrote:
Henry Baker:
It was my impression that most, if not all, iridium comes from outer space; there is very little indigenous iridium on the Earth's surface. There may be a lot in the Earth's core, but it's going to be a little difficult to mine it from there.
Volcanos are an adequate mechanism for having increased levels of iridium on the Earth's surface. There is sufficient iridium here that at least one recent paper argued that elevated concentrations of iridium in some desert wetlands "arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event". The argument was meant to counter a Younger Dryas impact hypothesis and thus may not adequately address the origin of the underlying, unconcentrated iridium.
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