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Gamma-ray bursts are a threat to life

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Re: Gamma-ray bursts are a threat to life

#81

Post by HCIdivision17 »

jchrisa wrote: post #68

How far along the Kardashev scale do we need to before we can build a shield?

At least Type I, but easily at Type II [0].

Here the trick is that a planet-scale barrier is needed, since we need to defend against tipping our ecosystem into chaos. If we're Type II, then we could theoretically just let the earth get whacked and restart using nearby systems to seed it. Kinda funny how a disaster stops being as terrible once you have backups:

Type 0: extinction

Type 1: mega-scale engineering effort to block GRB

Type 2: start over from scratch easily

[0] http://en.wikipedia.org/wiki/Kardashev_scale#Theoretical_exa...

Re: Gamma-ray bursts are a threat to life

#82

Post by Udo »

saiya-jin wrote: post #76
Udo wrote: post #71

Earlier quoted context omitted.

Neutrino detection in correlation with GRBs is problematic at best, because the events tend to be so far away and neutrino emissions are not expected to be focused into cones the same way EM and charged particles are, by virtue of not interacting with electromagnetic processes they'll be emitted in all directions. (There is some hypothetical neutrino/antineutrino emission within the GRB cone, but it's likely a weak s…

now, nothing. In future, possibly raise some sort of (EM) shield? Of course nothing to for us/our kids, but I am sure within few millenia this would be perfectly feasible (at least my imagination wishing so :)

We already have one of those and it's pretty darn powerful :) of course, if we're talking millennia of technological development, all bets are off - but by then we and the planet will look very different.

However, I think this needs to be stretched once more: there will most likely be no advance detection through neutrinos.

Re: Gamma-ray bursts are a threat to life

#83

Post by hanoz »

Udo wrote: post #71
neaanopri wrote: post #70

Does anybody know if a gamma-ray burst is preceded by an increased neutrino flux? I've heard that neutrinos will actually arrive at earth several hours before the light from a supernova. When the core of a star collapses, the light is physically prevented from coming outwards until the collapse is complete. Since the neutrinos move right through the gas, they are emitted as soon as the explosion occurs. Would detecti…

Neutrino detection in correlation with GRBs is problematic at best, because the events tend to be so far away and neutrino emissions are not expected to be focused into cones the same way EM and charged particles are, by virtue of not interacting with electromagnetic processes they'll be emitted in all directions. (There is some hypothetical neutrino/antineutrino emission within the GRB cone, but it's likely a weak s…

How useful a barrier is the earth itself for the initial burst? Would there be any benefit in arranging to be on the opposite side of it for the duration?

Re: Gamma-ray bursts are a threat to life

#84

Post by Udo »

hanoz wrote: post #83
Udo wrote: post #71

Earlier quoted context omitted.

Neutrino detection in correlation with GRBs is problematic at best, because the events tend to be so far away and neutrino emissions are not expected to be focused into cones the same way EM and charged particles are, by virtue of not interacting with electromagnetic processes they'll be emitted in all directions. (There is some hypothetical neutrino/antineutrino emission within the GRB cone, but it's likely a weak s…

How useful a barrier is the earth itself for the initial burst? Would there be any benefit in arranging to be on the opposite side of it for the duration?

If it's an exceptionally strong burst, yes. If it's not (which is very likely), there is no need.

Re: Gamma-ray bursts are a threat to life

#85

Post by atlantic »

Udo wrote: post #64
JonnieCache wrote: post #62

Earlier quoted context omitted.

Admittedly I did make a typo there but the diaspora is motivated/necessitated by the disaster.

It's an interesting typo, also because disaster literally means "bad star".

And the etymology of dis-aster is astrological: a negative event caused by an unfavourable planetary configuration, by "bad stars".

Re: Gamma-ray bursts are a threat to life

#86

Post by knodi123 »

Sophistifunk wrote: post #55
adrianN wrote: post #50

Earlier quoted context omitted.

A subterranean city won't protect your from a GRB.

Why not, if the extinction mechanism is disruption of the ozone layer?

Well, my understanding could be wrong, but it seemed like the risk is to the ecosystem, not to human bodies directly. We personally don't need to be protected from the burst itself.

Re: Gamma-ray bursts are a threat to life

#88

Post by sshumaker »

lucaspiller wrote: post #5

Let's assume this happened tomorrow, and it took another 500 million for life to evolve to what we would consider intelligent. Would anything of our civilisation be left? What would be the best way to leave a record that we existed?

I think we might be earth's last chance at an advanced civilization. We've depleted all of the readily available energy sources necessary for an emerging civilization (easily-accessible fossil fuels). It will take at least 500 million years for them to be replenished. And in one billion years, the increased luminosity from the sun will wipe out most advanced life due to runaway greenhouse effects. So there's a pretty narrow window in-between.

Re: Gamma-ray bursts are a threat to life

#90

Post by edgarvm »

crystaln wrote: post #29

Is this really an explanation for the Fermi paradox? Would a factor of 0.1 or even 0.01 really change the import of the Fermi paradox?

It's just an idea but I think any advanced civilization aware of threats of GRB would try to transmute from its organic form to avoid extinction.
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