Do nearby gamma ray busts/supernova damage *more* than just the ozone layer?

[Simfish]

http://en.wikipedia.org/wiki/Near-Earth_supernova

So we know that many people are putting hard constraints on the galactic habitability zone based on the presence of nearby supernova/gamma ray bursts. But if they *only* affect the ozone layer, then I doubt that it's as hard of a constraint as many people think it is.

For one thing - there is practically no ozone layer around the planets of red dwarfs (and possibly even low-mass K-stars like Epsilon Eridani and Alpha Centauri B - IMHO, K-stars offer the best prospects for life on other planets). Would a nearby supernova really do so much damage to planets around those stars?

For another thing, would a supernova really cause more damage than, say, the K/T extinction event 65 million years ago?

And then for a third point - is it really going to cause significant amounts of damage to marine life? Much of it is shielded from UV rays by layers of ocean water.

Then maybe Is it possible to survive through a gamma ray burst by geoengineering its impact out? is relevant for complex life too (although this response might be imperfect for now)

 

[Dotini]

http://www.nasa.gov/mission_pages/GLAST/news/fermi-thunderstorms.html

Ordinary thunderclouds are known to emit gamma rays, particle beams and hurl anti-matter, so these things obviously aren't too terrible. How can there be any harm in gamma rays from farther away?

Respectfully submitted,
Steve
Location: Seattle, WA

 

[Drakkith]

Gamma Radiation affects more than just the ozone layer. Given a large enough burst of Gamma rays there would be extensive injuries over the exposed hemisphere of the Earth. Marine life would be affected near the surface nearly as much as those on land, with the protection increasing the further down you go underwater.

Ordinary thunderclouds are known to emit gamma rays, particle beams and hurl anti-matter, so these things obviously aren't too terrible. How can there be any harm in gamma rays from farther away?

The difference is in the energy of the Gamma rays AND the shear amount. A supernova releases a huge amount of Gamma radiation, enough to pose a threat to us here on Earth if they are close enough. (Close enough being 10-100 light years I believe, but I'm not sure) So even after being spread out by a huge distance of travel there is still enough Gamma radiation to pose a severe threat. Luckily there are very few stars, if any, that will go supernova anytime soon in our stellar neighborhood, and they must be facing the correct way when they explode, making the event very improbable.

 

[Android Cat]

In light of the recent CERN CLOUD results, and the probable importance of gamma rays on cloud formation, has anyone thought about the possible climatic effects of gamma ray bursts from a nearby super nova? (I was thinking mainly of Betelgeuse at 640 ly, which could go off any moment in the next million years.)

Speculative hand waving:

I note that super nova remnant http://en.wikipedia.org/wiki/RX_J0852.0-4622" has been discovered at 650-700 ly, the explosion of which should have been visible on Earth roughly 1250 AD. (Unreported in Europe and China, but it was in the southern sky, constellation Vela.)

And I'll also note that the first signs of the http://en.wikipedia.org/wiki/Little_Ice_Age" also occurred roughly 1250 AD, but that's probably just a coincidence...

 

[Astronuc]

The gamma rays (synchrotron or brehmsstrahlung?) developed above thunderstorms are already part of the influence of weather. They've always been there, but only recently were they discovered.

The antimatter particles mentioned are positrons, and for gammas to produce positron-electron pairs, they must have a minimum energy of ~1.022 MeV. So what is the accelerating potential or process?

What is the anistropy of the gammas from thunderstorms?

In considering the effect of GRBs, one should consider the likely energy spectrum (low MeV vs 10-100 MeV range) and intensity, photon density or flux.

 

[Dotini]

The gamma rays (synchrotron or brehmsstrahlung?) developed above thunderstorms are already part of the influence of weather. They've always been there, but only recently were they discovered.

The antimatter particles mentioned are positrons, and for gammas to produce positron-electron pairs, they must have a minimum energy of ~1.022 MeV. So what is the accelerating potential or process?

I've been wondering about this myself, since the answers could resolve a number of questions in my mind.

http://www.newscientist.com/article/mg21128274.400-electric-ice-a-shock-to-the-solar-system.html
This article explains how charge separation can be created, structured, propagated and maintained in ice. This may be an important factor in explaining how some clouds can gather the energy necessary to generate the electron showers required to cause gamma rays and antimatter formation. The investigators find that at low temperatures water ice will preferentially form a crystalline structure that maintains the alignment of the water molecule dipole, thereby preserving charge separation.

http://faculty.washington.edu/ghp/images/stories/pubPDF/2003_Zheng.pdf
This paper delves into how charge separation and "long-range" alignment of molecular dipoles is achieved at room temperature with the simplest of inputs - water, sunlight and an hydrophilic surface. Liquid crystal in a gel-like form is involved. Pollock, one of the authors, suggests this process may be fundamental to nucleation and formation of clouds in the first place.

In thunderclouds it is thought that charges in the supercooled water are separated with positive at the top and negative at the bottom. If a column within the cloud on the order of a mile or two were structured in such a way that the molecules were more or less uniformly aligned, I can imagine the potential for a very powerful discharge. Here is where my science comes to a stop. It would be fun to hear what answers there are to be found!

Respectfully submitted,
Steve