1100 gamma ray bursts a day on Earth!

[Xamonas Chegwé]

http://www.bbc.co.uk/news/science-environment-30491840

Pretty much every thunderstorm produces a burst of gamma radiation. So why aren't there more Hulks about? Answer that one, Darwin!

[cronus]

They ride the lightning.

[JimC]

The process itself is interesting. From Wikipedia:

Thunderstorms can produce a brief pulse of gamma radiation called a terrestrial gamma-ray flash. These gamma rays are thought to be produced by high intensity static electric fields accelerating electrons, which then produce gamma rays by bremsstrahlung as they collide with and are slowed by atoms in the atmosphere. Gamma rays up to 100 MeV can be emitted by terrestrial thunderstorms, and were discovered by space-borne observatories.

[pErvinalia]

That might explain why Queenslanders and Floridians are a little strange in the head.

[laklak]

Apparently the new Lightning Capital of the World is Rwanda. Lightning and genocide, go together like a horse and carriage.

http://articles.orlandosentinel.com/200 ... -lightning

[MiM]

http://www.bbc.co.uk/news/science-environment-30491840

Pretty much every thunderstorm produces a burst of gamma radiation. So why aren't there more Hulks about? Answer that one, Darwin!

Because technically those are X-rays, not gamma. If they are called gamma-ray bursts, that would be because astronomers still confuse the two, by referring to fenomena that produce highly energetic X-rays, for gammabursts. I see no reason, why this confusion should be brought back here to planet earth.

And no-one has ever seen a Hulk produced by mere X-rays

[JimC]

http://www.bbc.co.uk/news/science-environment-30491840

Pretty much every thunderstorm produces a burst of gamma radiation. So why aren't there more Hulks about? Answer that one, Darwin!

Because technically those are X-rays, not gamma. If they are called gamma-ray bursts, that would be because astronomers still confuse the two, by referring to fenomena that produce highly energetic X-rays, for gammabursts. I see no reason, why this confusion should be brought back here to planet earth.

And no-one has ever seen a Hulk produced by mere X-rays

If they have a frequency above 1019 Hz, then they are gamma rays, whatever their source...

[MiM]

http://www.bbc.co.uk/news/science-environment-30491840

Pretty much every thunderstorm produces a burst of gamma radiation. So why aren't there more Hulks about? Answer that one, Darwin!

Because technically those are X-rays, not gamma. If they are called gamma-ray bursts, that would be because astronomers still confuse the two, by referring to fenomena that produce highly energetic X-rays, for gammabursts. I see no reason, why this confusion should be brought back here to planet earth.

And no-one has ever seen a Hulk produced by mere X-rays

If they have a frequency above 1019 Hz, then they are gamma rays, whatever their source...

Maybe back when you went to school, but not anymore . Distingushing gamma and x-rays by source is the only sane way to distinguish them, as dividing them by frequency is completely arbitrary. But I do agree, that we would need a word for high energy photons, that would cover both.

[Xamonas Chegwé]

http://www.bbc.co.uk/news/science-environment-30491840

Pretty much every thunderstorm produces a burst of gamma radiation. So why aren't there more Hulks about? Answer that one, Darwin!

Because technically those are X-rays, not gamma. If they are called gamma-ray bursts, that would be because astronomers still confuse the two, by referring to fenomena that produce highly energetic X-rays, for gammabursts. I see no reason, why this confusion should be brought back here to planet earth.

And no-one has ever seen a Hulk produced by mere X-rays

If they have a frequency above 1019 Hz, then they are gamma rays, whatever their source...

Maybe back when you went to school, but not anymore . Distingushing gamma and x-rays by source is the only sane way to distinguish them, as dividing them by frequency is completely arbitrary. But I do agree, that we would need a word for high energy photons, that would cover both.

What does it matter the source? Electromagnetic radiation is electromagnetic radiation. One photon differs from another only in wavelength/frequency/energy. Where they come from is irrelevant.

[JimC]

It sounds like MiM wants to define gamma rays as photons produced by events in a nucleus...

[MiM]

It sounds like MiM wants to define gamma rays as photons produced by events in a nucleus...

True, except that it is not me who wants to make that definition. While, I admit that there is no absolute consensus of how to define x- and gamma rays, one of the most used ways is exactly that.

[JimC]

It sounds like MiM wants to define gamma rays as photons produced by events in a nucleus...

True, except that it is not me who wants to make that definition. While, I admit that there is no absolute consensus of how to define x- and gamma rays, one of the most used ways is exactly that.

What about the photons released by the mutual annihilation of electron-positron pairs? Non-nuclear, yet definitely gamma rays...

[Xamonas Chegwé]

It sounds like MiM wants to define gamma rays as photons produced by events in a nucleus...

True, except that it is not me who wants to make that definition. While, I admit that there is no absolute consensus of how to define x- and gamma rays, one of the most used ways is exactly that.

It's monkeys all over again!

Seriously, defining types of electromagnetic radiation by their origins is a bit silly IMO. Especially where the ranges overlap so much. A photon of 1019Hz is exactly the same thing whether you call it "gamma ray", "X ray" or "Clarence". Bloody scientists ought to sort their nomenclatures out!

[pErvinalia]

"Clarence" rays are a bit gayer than 'x' and 'gamma' rays.

[MiM]

It sounds like MiM wants to define gamma rays as photons produced by events in a nucleus...

True, except that it is not me who wants to make that definition. While, I admit that there is no absolute consensus of how to define x- and gamma rays, one of the most used ways is exactly that.

What about the photons released by the mutual annihilation of electron-positron pairs? Non-nuclear, yet definitely gamma rays...

Cleverly put trap, you almost got me on that one. But strictly speaking that radiation has its own name (annihilation radiation/photons). But yes, I am prepared to accept those (and similar) as (annihilation) gamma in casual language.

On the other hand, what about the characteristic radiation coming from the K-shell of (say) a bismuth-214 atom, after the decay of led-214? It has energies ranging from 75-90 keV, which is roughly twice the cutoff you suggested, but they are surely still x-rays... At the same time the decay releases real gammas with a lower energy, than these x-rays.