dbooksta wrote:
If I'm reading the description correctly and looking at the aggregated signals: This galaxy 5 billion light years away has a burst that spans about half a degree? The same as the sun and moon? How can that possibly be right?
Probably just the resolution of the telescope:
https://en.wikipedia.org/wiki/Fermi_Gamma-ray_Space_Telescope wrote:
<<The Fermi Gamma-ray Space Telescope's Large Area Telescope (LAT) imaging gamma-ray detector (a pair-conversion instrument) detects photons with energy from about 20 MeV to 300 GeV.
The resolution of its images is a few arc minutes for the highest-energy photons [but only about] 3 degrees at 100 MeV.>>
HomeAl0ne wrote:
... I seem to remember something about gamma-ray detectors using concentric metal tubes as lenses...
That's how x-ray imaging systems sometimes work (that is, for photons some thousand times less energetic than the sort this gamma ray sensor is designed for). The gamma ray detector detects photons as they plow through thin conductive foil layers...
Click to play embedded YouTube video.
http://imagine.gsfc.nasa.gov/science/toolbox/gamma_detectors2.html wrote:
This animation shows how the Large Area Telescope on the Fermi Gamma-ray Telescope works. A gamma ray (purple) interacts with the detector, creating an electron-positron pair which cascade down the tower. Using the paths that the electron and positron take through the telescope, the direction of the original gamma-ray can be determined (shown in purple). (Credit: NASA's Goddard Space Flight Center Conceptual Image Lab)
A pessimist is nothing more than an experienced optimist
It's an interesting video. I now though find I'm mentally singing "Gamma-ray rain drops keep falling on my head...." . It's also making me think of the photon torpedoes used in Star Trek .
. It's also making me think of the photon torpedoes used in Star Trek 
.