[meteorite-list] OT: Listening To Fermi ELEs GRBs and lifetimes of civilizations

[MEM]

----- Original Message ----
> From: Meteorites USA <eric at meteoritesusa.com>
....However,  I've got an interesting question about perspective and  time.   If 
a  child looked out the window of a house for a mere 32/1000th of  a second and 
formed a conclusion that horses do not exist, would you say he's  correct?


Somewhere out in cyberspace is a well reasoned presentation that gamma ray burst 
(GRB) and super novae, in general, act as limiters to long-lived and 
highly-developed civilizations.  Statistically, by the time a civilization 
"matures" in technology, it has also dodged the gamma ray "bullet" in the cosmic 
"Russian Roulette" handgun so many times, it gets moved to the top of the list 
as a "target"( i.e. The longer a star region goes without a GRB, owing to star 
lifetimes etc,  the higher its statistical probability rises that it will be in 
the blast zone of a GRB: two random but codependent events).  This results in a 
reset of complex life to lower life forms.  


The study argues, that given relatively short "statistical life-spans", GRBs 
et.al.  remove "technologically-capable civilizations" from the pool of 
listeners.  The bottom line is that all intelligent/technological life will 
eventually bite the GRB bullet and SETI might be trying to sample an already 
depleted pool of participants.

I don't have the numbers they used/correlated for the study or remember the 
theoretical life spans. However couple that with all other Extinction Level 
Events(ELEs) by asteroid impacts, runaway vulcanism, and etc., the probability 
of reaching technical sophistication is further diminished. We on earth, are 
likely under the GRB gun more than our Ordovician Fish ancestors were. We know 
that eventually the trigger will be pulled and we might be the shooting arcade 
ducky that gets reset-Pling!. The question remains regarding timelines: Which of 
the two events will be be more likely to encounter first?  Experience first 
contact with another intelligent life form or GRB extinction ourselves.

Mammal-like creatures were beginning to develop in the Permian (250mybp±) yet a 
massive ELE wiped out 95% of life and reptiles kept the advantage for the next 
135± million years. Followed by another 65± million year reset /life form 
expansion. Only developments in the last 100 years brought mankind "Homo 
Technicius" into the technological level to even start looking for other 
brothers and sisters in the fraternity.  Had the Permian extinction not 
happened, would intelligent life  arose 85 my earlier only to be snuffed out 20 
mil years later?

Elton