The Beauty and the Burst

There are 4 comments on the AccuWeather.com story from Dec 8, 2013, titled The Beauty and the Burst. In it, AccuWeather.com reports that:

Gamma-ray bursts are the most energetic and luminous explosions in the known universe.

Join the discussion below, or Read more at AccuWeather.com.

“Geologist [I'm Climate Change]”

Since: Mar 07

formerly Nuneaton

#1 Dec 9, 2013
Nice article.

Problem with the theory of gamma ray bursts causing a mass extinction lies in its short duration. An average gamma ray burst would last about 10 seconds (the longest from disc/jet effects in a massive star & core black hole accretion would last 5 minutes). As the Earth rotates once in 24 hours (a little less time in the Ordovician), a gamma ray burst would irradiate a hemisphere. Even with maximum ozone depletion taken into account the result would be a total of 1/2 of the ozone layer lost which would rapidly be regenerated before mix time. As the Ordovician mass extinction was global rather than local, the cause would not be a GRB.

One other note is that the classic GRB types would typically be globular clusters @ extreme distance (usually a result of core collapse and accretion of stars onto a core supergiant which grows in mass with each collision until the evolving iron core finally goes down (stars could be anywhere from 15 to 500 solar masses @ that point), following the GRB the black hole then gets the munchies & ends up as an intermediate mass black hole in a core condensed globular cluster (like M15).

For close GRB types the best candidate is a massive supergiant in the galactic disc with a gamma cassiopieae signature & LBV luminosity such as eta carinae, AG Carinae, P cygni etc. The GRB erupts out of both poles of the star once the iron core becomes a black hole with (as with distant stars the GRB being a circularly polarised gamma ray laser. The problem is that a close GRB will have a diameter approaching that of Jupiter (more miss than hit). If a close one DID hit the result is likely to be wholesale evaporation of the surface hemisphere of the planet & likely gamma ray induced beta decay of susceptible elements (ouch).

That would however be a mass extinction scenario.

Have a nice day: Ag

“'QUANDARY'”

Since: Oct 12

Cheshire UK

#2 Dec 10, 2013
Adrian Godsafe MSc wrote:
Nice article.
Problem with the theory of gamma ray bursts causing a mass extinction lies in its short duration. An average gamma ray burst would last about 10 seconds (the longest from disc/jet effects in a massive star & core black hole accretion would last 5 minutes). As the Earth rotates once in 24 hours (a little less time in the Ordovician), a gamma ray burst would irradiate a hemisphere. Even with maximum ozone depletion taken into account the result would be a total of 1/2 of the ozone layer lost which would rapidly be regenerated before mix time. As the Ordovician mass extinction was global rather than local, the cause would not be a GRB.
One other note is that the classic GRB types would typically be globular clusters @ extreme distance (usually a result of core collapse and accretion of stars onto a core supergiant which grows in mass with each collision until the evolving iron core finally goes down (stars could be anywhere from 15 to 500 solar masses @ that point), following the GRB the black hole then gets the munchies & ends up as an intermediate mass black hole in a core condensed globular cluster (like M15).
For close GRB types the best candidate is a massive supergiant in the galactic disc with a gamma cassiopieae signature & LBV luminosity such as eta carinae, AG Carinae, P cygni etc. The GRB erupts out of both poles of the star once the iron core becomes a black hole with (as with distant stars the GRB being a circularly polarised gamma ray laser. The problem is that a close GRB will have a diameter approaching that of Jupiter (more miss than hit). If a close one DID hit the result is likely to be wholesale evaporation of the surface hemisphere of the planet & likely gamma ray induced beta decay of susceptible elements (ouch).
That would however be a mass extinction scenario.
Have a nice day: Ag
Nahh! we had some of that a few years ago and it didn't even ruffle the grass!!

Since: Aug 11

Location hidden

#3 Dec 10, 2013
Coprolite1 wrote:
<quoted text>Nahh! we had some of that a few years ago and it didn't even ruffle the grass!!
I knew a guy that got bombarded with gamma radiation. You didn't want to make him angry!

“Geologist [I'm Climate Change]”

Since: Mar 07

formerly Nuneaton

#4 Dec 11, 2013
normal Aussie wrote:
<quoted text>
I knew a guy that got bombarded with gamma radiation. You didn't want to make him angry!
Lots of people like him though, seems to be the ultimate in going green.

Have a nice day: Ag

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