[ RadSafe ] Astrophysicists Report Radioactive Cobalt in Supernova Explosion

[KARAM, PHILIP]

Neat stuff! There were two great papers right around 1999-2001 (can't remember the specifics). One, by Ellis, Fields, and Schramm calculated the amount of radioactive supernova debris that would be swept up by the Earth in the aftermath of a nearby supernova. Just a year or two later a second paper (by Knie et al. if I remember correctly) reported finding live Fe-60 (half-life about 1.5 million years) in deep sea sediments. They felt that the Fe-60 was correlated with the Local Bubble. Since that time I seem to recall that others have found more Fe-60 in other sediments, and that even some Pu-244 (60 million year half-life) has been found that is also most likely supernova debris.

Andy


P. Andrew Karam, PhD, CHP
NYPD Counterterrorism
One Police Plaza, Room 1109
New York, NY 10038
(718) 615-7055 (desk)
(646) 879-5268 (mobile)


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Jaro Franta
Sent: Tuesday, September 23, 2014 11:03 AM
To: 'The International Radiation Protection (Health Physics) Mailing List'
Subject: Re: [ RadSafe ] Astrophysicists Report Radioactive Cobalt in Supernova Explosion

Andy et-al, FYI.....

http://science.nasa.gov/science-news/science-at-nasa/2014/26aug_localbubble/

Evidence for Supernovas Near Earth
August 26, 2014


 Jaro
^^^^^^^^^^^^^^^^^^^^^^^^^



-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of KARAM, PHILIP
Sent: September-09-14 10:13 AM
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] Astrophysicists Report Radioactive Cobalt in Supernova Explosion

I remember looking at this as well - a high-energy gamma ray burst in the Andromeda galaxy (about 3 million light-years away) could actually expose an astronaut here to about a rad (10 mGy). 

There was some speculation in the late 1990s that periodic gamma ray bursts might explain why we haven't been contacted by alien civilizations yet - wondering if they periodically cause galaxy-wide mass extinctions. That seems dubious, given that even a "long" gamma ray burst only lasts a few seconds - enough to sterilize half a planet, but not the whole thing. Plus, the thick dust and gas clouds in the galactic core would help to shield the opposite side of the galaxy from the worst effects (although normal dust and gas clouds in the disk are so scanty as to offer very little in the way of attenuation).

There was also some speculation that neutrinos from supernovae might cause mass extinctions - there are about 10^57 neutrinos produced during the collapse of a giant star into a neutron star. But the interaction cross-section of SN-spectrum neutrinos is too small and, even with one very nearby, the dose would be too small to cause health problems. Interestingly, the biggest concern from a nearby supernova will likely be ozone depletion and the formation of opaque chemicals in the atmosphere. Some astronomers in Texas (Scalo an Wheeler) suggested that a climate-altering supernova might occur close enough to have a measurable impact every 10,000-100,000 years.

Andy 


P. Andrew Karam, PhD, CHP
NYPD Counterterrorism
One Police Plaza, Room 1109
New York, NY 10038
(718) 615-7055 (desk)
(646) 879-5268 (mobile)



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