Astroparticle Physics

316 16 GlossaryHawking radiationHawking temperatureHEAOHeisenberg’s uncertaintyprincipleheliocentricheliosphereHertzsprung–Russell diagramHiggs bosonHiggs fieldhorizonhorizon problemhot dark matterThe gravitational field energy of a black hole allows to createparticle–antiparticle pairs of which, for example, one can be absorbedby the black hole while the other can escape if the processoccurs outside the event horizon. By this quantum process blackholes can evaporate because the escaping particle reduces the energyof the system. The time scales for the evaporation of largeblack holes exceeds, however, the age of the universe considerably.The temperature of a black hole manifested by the emission ofHawking radiation.High Energy Astronomy Observatory, X-ray satellite.Position and momentum of a particle cannot be determined simultaneouslywith arbitrary precision, x p ≥ ¯h/2. This uncertaintyrelation refers to all complementary quantities, e.g., also to the energyand time uncertainty.Centered on the Sun.The large region starting at the Sun’s surface and extending to thelimits of the solar system.Representation of stars in a colour–luminosity diagram. Stars withlarge luminosity are characterized by a high colour temperature,i.e., shine strongly in the blue spectral range.Hypothetical particle as a quantum of the Higgs field predicted inthe framework of the Standard Model to give masses to fermionsvia the mechanism of spontaneous symmetry breaking. Named afterthe Scottish physicist Peter Higgs.A hypothetical scalar field which is assumed to be responsible forthe generation of masses in a process called spontaneous symmetrybreaking.The observable range of our universe. The radius of the observableuniverse corresponds to the distance that light has travelled sincethe Big Bang.In classical cosmology regions in the sky separated by more than ≈2 ◦ are causally disconnected. Experimentally it is found that theystill have the same temperature. This can naturally be explained byan exponential expansion in the early universe which has smoothedout existing temperature fluctuations.Relativistic dark matter. Neutrinos are hot-dark-matter candidates.