Why can't we have earthbound X-ray observatories?X-ray observatories must be placed high above the Earth's surface because the Earth's atmosphere absorbs x-rays. This means that the ultra-precise mirrors and detectors -- together with the sophisticated electronics that convey the information back to Earth -- must be able to withstand the rigors of a rocket launch and operate in the hostile environment of space.
Revised: August 31, 2011