Search results
Results from the WOW.Com Content Network
Long before experiments could detect gamma rays emitted by cosmic sources, scientists had known that the universe should be producing them. Work by Eugene Feenberg and Henry Primakoff in 1948, Sachio Hayakawa and I.B. Hutchinson in 1952, and, especially, Philip Morrison in 1958 [6] had led scientists to believe that a number of different processes which were occurring in the universe would ...
A cosmic ray or high-energy gamma ray striking an atom in the upper atmosphere generates a cascade of particles known as an air shower. This cascade of particles are traveling near the speed of light and generate Cherenkov radiation as they pass through the atmosphere and the water in the Milagro experiment.
An example is "gamma rays" from lightning discharges at 10 to 20 MeV, and known to be produced by the bremsstrahlung mechanism. Another example is gamma-ray bursts, now known to be produced from processes too powerful to involve simple collections of atoms undergoing radioactive decay.
Either a long-duration burst in which the presence of a bright supernova is ruled out, or a short-duration burst with extremely long-lasting gamma-ray emission. GRB 080319B: z = 0.937: Swift: The most (optically) luminous event of any nature observed in the universe to date. By far the brightest optical afterglow of any gamma-ray burst. GRB 080916C
The Pound–Rebka experiment monitored frequency shifts in gamma rays as they rose and fell in the gravitational field of the Earth. The experiment tested Albert Einstein 's 1907 and 1911 predictions, based on the equivalence principle , that photons would gain energy when descending a gravitational potential, and would lose energy when rising ...
Two-photon physics, also called gamma–gamma physics, is a branch of particle physics that describes the interactions between two photons. Normally, beams of light pass through each other unperturbed. Inside an optical material, and if the intensity of the beams is high enough, the beams may affect each other through a variety of non-linear ...
The radiation from the general neighborhood, including the accretion disk, is affected by the nature of the central black hole. Assuming Einstein's theory is correct, astrophysical black holes are described by the Kerr metric. (A consequence of the no-hair theorems.) Thus, by analyzing the radiation from such systems, it is possible to test ...
Background radiation is largely homogeneous and isotropic. A slight detectable anisotropy is present which correlates to galaxy filaments and voids. [2] [3] The discovery (by chance in 1965) of the cosmic background radiation suggests that the early universe was dominated by a radiation field, a field of extremely high temperature and pressure. [4]