PDA

View Full Version : -- T G F --



astromark
2010-Feb-11, 01:29 AM
:eek: Terrestrial Gamma-ray Flashes. -- Wow:eh:

Having just read the NASA news sites page on this. I now want to know a great deal more of this Life threatening natural event. Its associated with lightning but as yet we do not know if it triggers or is triggered by lightning. That it lasts at best a Milli-second or two is not any comfort if it could fry your brain. If any of you have a link to more information than I have I would be pleased...? mark.

phunk
2010-Feb-11, 01:37 AM
Why do you think they are life threatening?

astromark
2010-Feb-11, 01:56 AM
Gamma-ray Flashes ...
is it safe to be zapped by one of these ?
The NASA article does seem to suggest some danger...
Not so much if at all to ground dwelling life but, to air travelers...
Go to NASA NEWS and read it.
I just want to know more than the almost nothing I do now.

Van Rijn
2010-Feb-11, 02:23 AM
Gamma-ray Flashes ...
is it safe to be zapped by one of these ?
The NASA article does seem to suggest some danger...
Not so much if at all to ground dwelling life but, to air travelers...
Go to NASA NEWS and read it.
I just want to know more than the almost nothing I do now.

I did a bit of searching (there is more than one article on terrestrial gamma ray flashes on "Nasa News") and found this:

http://science.nasa.gov/headlines/y2010/10feb_friendlyskies.htm

Quoting from that article:


In a recent study,* scientists estimated that airline passengers could be exposed to 400 chest X-rays worth of radiation by being near the origin of a single millisecond blast. Joe Dwyer of the Florida Institute of Technology took part in that research, which used observations from NASA's Reuven Ramaty High Energy Solar Spectroscopic Imager, or RHESSI, to estimate the danger TGFs pose.

"We believe the risk of encountering a TGF in an airplane is very small," says Dwyer. "I wouldn't hesitate to take a flight. Pilots already avoid thunderstorms because of turbulence, hail, and lightning, and we may just have to add TGFs to the list of reasons to steer clear of those storms."

But, he stresses, "it's worth looking into."

Okay, 400 chest x-rays sounds like a lot, but what does it mean? I don't know how much of a dosage is typical today in a chest x-ray, so did a little more Googling. For comparision, here's an unrelated article talking about an FDA initiative to reduce radiation exposure:

http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm200085.htm

Quoting from that article:


For example, the radiation dose associated with a CT abdomen scan is the same as the dose from approximately 400 chest X-rays. In comparison, a dental X-ray calls for approximately one-half the radiation dose of a chest X-ray. Both diagnostics serve important, sometimes critical, public health needs.

If they're using the same numbers as a basis for comparison, it sounds like something you would prefer to avoid, but isn't going to kill you from radiation sickness.

korjik
2010-Feb-11, 04:03 AM
You are far more likely to get hit by lightning from a thunderstorm that you are to get radiation sickness from a TGF

astromark
2010-Feb-11, 04:45 AM
So it would seem that by the fact that these gamma-ray flashes are higher in the atmosphere than we are normally and that as that your standard commuter jet tends to avoid towering cumulus active cells as they are the birth place of hail wind shear and lightning... So I can go ahead and travel with scant regard to this Terrestrial Gamma-ray Flashes... good.