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I've read many facts from NASA's webpage.. Sometimes they tell, (for example) "NASA's Chandra X-Ray Observatory discovered this ultra-luminous X-Ray source (about 15 million LY) which shows an extraordinary outburst..."

My question is.. Is it possible to obtain those electromagnetic radiation (Infra-red, Visible, UV or X-Rays) from such a long range? If so.. How?

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Photons go on for ever unless they hit something and space is pretty empty. So unless there is a grain of dust, or a star in the way a photon will travel across the universe.

Paradoxically it's harder for high energy photons such as x-rays to travel large distances in space. Because of their energy they can be effected by passing close to even something as small as a single electron.

The other reason we still don't see X-ray objects at the same vast distances that we see infrared sources is that, even with Chandra, x-ray telescopes are smaller and less sensitive than optical or radio telescopes and so we need more photons from the source, so it needs to be brighter or closer.

The reason distant objects are fainter isn't so much that photons are blocked - it's that the photons spread out into a sphere. So at 2x the distance away they are spread over an area 4x as big and so are diluted.

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If you want to detect the photons coming toward you, you need to reflect them into your detector. Optical telescope mirrors are the size of a house while x-ray telescopes are the size of a garbage can, and only about 10% of their area is usable, - so the chances of a passing photon being reflected into the detector is smaller. So we see less x-ray photons and so need a much brighter or nearer source to detect it –  Martin Beckett Aug 4 '12 at 14:41

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