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Tomographic reconstruction: Projection, Back projection and Filtered back projection. Tomographic reconstruction is a type of multidimensional inverse problem where the challenge is to yield an estimate of a specific system from a finite number of projections. The mathematical basis for tomographic imaging was laid down by Johann Radon.
Focal plane tomography uses the fact that the focal plane appears sharper, while structures in other planes appear blurred. By moving an X-ray source and the film in opposite directions during the exposure, and modifying the direction and extent of the movement, operators can select different focal planes which contain the structures of interest.
In this sample of images from 2004, bright X-ray arcs of low energy (0.1 – 10 keV) are generated during auroral activity. The images are superimposed on a simulated image of Earth. The color code of the X-ray arcs represent brightness, with maximum brightness shown in red. Distance from the North pole to the black circle is 3,340 km (2,080 mi).
Earth might once have been in danger – but is safe now, scientists say Planets like Earth facing threat from stars blasting intense X-rays at their atmospheres, Nasa study suggests Skip to main ...
X-rays start at ~0.008 nm and extend across the electromagnetic spectrum to ~8 nm, over which the Earth's atmosphere is opaque. X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects.
X-ray optics is the branch of optics dealing with X-rays, rather than visible light.It deals with focusing and other ways of manipulating the X-ray beams for research techniques such as X-ray diffraction, X-ray crystallography, X-ray fluorescence, small-angle X-ray scattering, X-ray microscopy, X-ray phase-contrast imaging, and X-ray astronomy.
Scientists used the most powerful laboratory source of radiation in the world to mimic the threat
Sgr A* possesses roughly 4 million times the mass of our sun and is located about 26,000 light-years from Earth. A light-year is the distance light travels in a year, 5.9 trillion miles (9.5 ...