Gamma Ray Earth !! ...? (APOD 03Jun06)

brianclark · Post by **brianclark** » Sat Jun 03, 2006 7:55 am

Looking at today's Gamma Earth...........if you consider Chernobyl, Hiroshima, Christmas Island and Maralinga............it's quite uncanny but maybe fits the image ?

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harry · Post by **harry** » Sat Jun 03, 2006 8:38 am

Hello brianclark

re link
http://antwrp.gsfc.nasa.gov/apod/ap060603.html

its not us bad as it looks

Brightest near the edge and faint near the center, the picture indicates that the gamma rays are coming from high in Earth's atmosphere. The gamma rays are produced as the atmosphere interacts with high energy cosmic rays from space, blocking the harmful radiation from reaching the surface.

l3p3r · Post by **l3p3r** » Sat Jun 03, 2006 1:03 pm

hi brianclark,
considering its a 7 year exposure... and this observatory was placed in a 450km orbit (likely not equatorial), I would say that its unlikely the spots represent exact locations as you suggest

on the other hand I have no idea how they went about taking that image... it seems a little unlikely that they got an image with such an emphasis on one side over a whole 7 years... am I missing something?

harry · Post by **harry** » Sun Jun 04, 2006 2:55 am

Hello All

Your right I3p3r

It is a composite image over time and therefore location is a problem and therefore not missing in the sense of the word.

Qev · Post by **Qev** » Sun Jun 04, 2006 7:07 am

It's also pretty unlikely that there are any gamma-ray sources on the surface of the planet that would be capable of penetrating the atmosphere into space to be visible to the satellite. If there were, we'd be in some kind of trouble.

harry · Post by **harry** » Sun Jun 04, 2006 7:37 am

Hello Qev

Imagine if there was, evlution of man would not have taken place as we know it.

We could have been looking at the PLanet of the Apes.

Thus no means of comminication with outer space.

markmark · Post by **markmark** » Mon Jun 05, 2006 1:58 pm

I understand why the atmosphere shows the preponderance of gamma rays, but, why do they show up primarily on the perimeter of the image? The whole of the image is covered with atmosphere.

Pete · Post by **Pete** » Mon Jun 05, 2006 3:17 pm

Good question - I'd think that's because the line of sight through the edges of Earth's disk passes through the most amount of atmosphere.