[Taxacom] Supernovae supposedly causing evolutionary effects (the Fe-60 fallacy?)

Kenneth Kinman kinman at hotmail.com
Thu May 30 08:55:25 CDT 2019


Dear All,
       The more arid and cooler conditions in Africa (and bipedalism in our ancestors) and the extinction of that gigantic shark do seem to be connected.  But instead of radiation-induced mutations, global climate cooling during the Pliocene makes far more sense (that shark was overly dependent on warm seas).  The question is what caused this cooling globally.
        As far back as 2004, physicists began speculating that these supernovae perhaps caused the cooling by increasing global cloud cover.   But note that such research comes from radioactive Fe-60 studies, and its half-life just happens to be 2.6 million years.  So supernovae could have easily been showering Earth with particles, radiation, and Fe-60 for billions of years and the Fe-60 would be undetectable before the late Cenozoic.  So that doesn't make much sense either (probably lots of such supernovae back in the very warm Eocene).
        So I would advise physicists to stop trying to connect supernovae explosions (especially based on Fe-60) to biological events.  The gradual cooling of climate during the late Cenozoic was most likely due to factors like continental drift and changing ocean currents (perhaps including the final closure of the Isthmus of Panama).  That giant shark couldn't take the cooling and the sea-level drop shrinking its habitat.  On the other hand, although our ancestors in Africa saw their forest habitat shrinking as well, it turned out to be a blessing in disguise for us (causing increased bipedalism and all that followed from that).
                        ------------Ken Kinman

2004 article that may have started all of this:  https://pdfs.semanticscholar.org/2be3/d584041a87604a4d2def5f2329de23934af5.pdf

________________________________
From: Kenneth Kinman <kinman at hotmail.com>
Sent: Tuesday, May 28, 2019 6:12 PM
To: taxacom; John Grehan
Subject: Re: [Taxacom] More fairy tales from evolution

Hi John,
       Some press coverage seems to love the hypotheses of Dr. Melott and colleagues.  A couple of years ago it was about such bursts of cosmic radiation (muons in particular) causing an extinction of marine megafauna at the end of the Pliocene.  And another hypothesis that the increase in mutation rates caused disparities between molecular clocks and the fossil record.  Here are just three examples (in the first one he suggests "due to the importance of highly penetrating muon irradiation, the disparity should be magnified for megafauna"):

     (1)  "A Possible Role for Stochastic Astrophysical Ionizing Radiation Events in the Systematic Disparity between Molecular and Fossil Dates."         https://www.liebertpub.com/doi/10.1089/ast.2016.1527

    (2)  "Muon Radiation Dose and Marine Megafaunal Extinction at the end-Pliocene Supernova":    https://www.biorxiv.org/content/10.1101/240093v1.full

    (3)  "Researchers consider whether supernovae killed off large ocean animals at dawn of Pleistocene":  https://phys.org/news/2018-12-supernovae-large-ocean-animals-dawn.html

________________________________
From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> on behalf of John Grehan via Taxacom <taxacom at mailman.nhm.ku.edu>
Sent: Tuesday, May 28, 2019 1:52 PM
To: taxacom
Subject: [Taxacom] More fairy tales from evolution

Evolution is definitely not a science. Its all about fairy tails (pun
intended). Here's the latest. The sooner we get honest to good fairy tails
(Creationism) in our schools the better. At least they are honest about
miracles. Good grief.

https://www.msn.com/en-us/news/technology/exploding-stars-led-to-humans-walking-on-two-legs-radical-study-suggests/ar-AAC25BS?li=BBnbcA1


According to the researchers, a series of stars in our corner of the Milky
Way exploded in a cosmic riot that began about 7m years ago and continued
for millions of years more. The supernovae blasted powerful cosmic rays in
all directions. On Earth, the radiation arriving from the cataclysmic
explosions peaked about 2.6m years ago.

The surge of radiation triggered a chain of events, the scientists argue.
As cosmic rays battered the planet, they ionised the atmosphere and made it
more conductive. This could have ramped up the frequency of lightning
strikes, sending wildfires raging through African forests, and making way
for grasslands, they write in the Journal of Geology. With fewer trees at
hand in the aftermath, our ancient ancestors adapted, and those who walked
upright thrived.

That, at least, is the thinking. In the history of human evolution, walking
upright dates back at least 6m years to Sahelanthropus, an ancient species
with both ape and human features discovered from fossil remains found in
Chad. One prominent theory is that climate change transformed the
landscape, leaving savannah where trees once stood.

One of the study’s authors, Adrian Melott of the University of Kansas, said
ancient human relatives were already dabbling with standing upright before
the effects of any supernovae took hold. But he believes the violent
explosions still played a role. “Bipedalism had already gotten started, but
we think this may have given it a strong shot in the arm,” he said.

“Lightning has long been thought to be the primary cause of fires before
humans had a role, and with a lot of fires you get the destruction of a lot
of habitat,” Melott said. “When the forests are replaced with grasslands,
it then becomes an advantage to stand upright, so you can walk from tree to
tree, and see over the tall grass for predators.”

The cosmic rays from one star known to have exploded about 164 light years
from Earth would have increased the ionisation of the atmosphere 50-fold,
the scientists calculate. Cosmic rays ionise the atmosphere when they knock
electrons out of the atoms and molecules they slam into in the air. Cosmic
rays normally only ionise the upper reaches of the atmosphere, but powerful
ones from nearby supernovae can penetrate the entire depth of the
atmosphere, ionising it all the way to the ground. “We are sure this would
have increased lightning strikes, but lightning initiation is not well
understood, so we cannot put a number on it,” Melott said.
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