Editing Electromagnetic spectrum (section)

=== X-rays ===
{{Main|X-rays}}
After UV come [[X-ray]]s, which, like the upper ranges of UV are also ionizing. However, due to their higher energies, X-rays can also interact with matter by means of the [[Compton scattering|Compton effect]]. Hard X-rays have shorter wavelengths than soft X-rays and as they can pass through many substances with little absorption, they can be used to 'see through' objects with 'thicknesses' less than that equivalent to a few meters of water. One notable use is diagnostic X-ray imaging in medicine (a process known as [[radiography]]). X-rays are useful as probes in high-energy physics. In astronomy, the accretion disks around [[neutron star]]s and [[black hole]]s emit X-rays, enabling studies of these phenomena. X-rays are also emitted by [[stellar corona]] and are strongly emitted by some types of [[nebulae]]. However, [[X-ray telescope]]s must be placed outside the Earth's atmosphere to see astronomical X-rays, since the great depth of the [[atmosphere of Earth]] is opaque to X-rays (with [[area density|areal density]] of 1000 g/cm<sup>2</sup>), equivalent to 10 meters thickness of water.<ref>Koontz, Steve (26 June 2012) [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012405.pdf Designing Spacecraft and Mission Operations Plans to Meet Flight Crew Radiation Dose] {{Webarchive|url=https://web.archive.org/web/20170502131715/https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120012405.pdf |date=2017-05-02 }}. NASA/MIT Workshop. See pages I-7 (atmosphere) and I-23 (for water).</ref> This is an amount sufficient to block almost all astronomical X-rays (and also astronomical gamma rays—see below).