An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (30×1015 Hz to 30×1018 Hz) and energies in the range 124 eV to 124 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it on November 8, 1895. He named it X-radiation to signify an unknown type of radiation. Spellings of X-ray(s) in English include the variants x-ray(s), xray(s), and X ray(s).
http://www.astronomy.com/Content/Dynamic/Articles/000/000/001/604djcxv.asp
XMM-Newton studies the X-ray universe from Earth orbit.
ESA
A mystery that has been haunting the fields of physics and cosmology has just grown deeper. Dark energy, that stealthy ghost that lurks in the...
Does anyone remember when Pravda only told the government's lies? I am posting this as a reminder that IMHO, Pravda is not a valid news source.
http://english.pravda.ru/science/19/94/377/11797_phenomenon.html
I'm having a little bit of a problem with this one. Here's the question:
X-ray pulses from Cygnus X-1, a celestial x-ray source, have been recorded during high-altitude rocket flights. The signals can be interpreted as originating when a blob of ionized matter orbits a black hole with a...
Heres the problem:
An x-ray tube used for cancer therapy operates at 4.0 MV, with a beam current of 25 mA striking the metal target.Nearly all of this power is transferred to a stream of water flowing through the holes drilled in the target. What rate of flow, in Kg/sec, is needed if the...
" To the eye, she is dressed in a skirt and blazer in dark, businesslike colors. On the monitor she is naked..."
http://news.yahoo.com/news?tmpl=story2&u=/030625/168/4i6lv.html&e=1&ncid=1756