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- Direct detection of dark matter is the science of attempting to directly measure dark matter collisions in Earth-based experiments. Modern astrophysical measurements, such as from the Cosmic Microwave Background, strongly indicate that 85% of the matter content of the universe is unaccounted for. Although the existence of dark matter is widely believed, what form it takes or its precise properties has never been determined. There are three main avenues of research to detect dark matter: attempts to make dark matter in accelerators, indirect detection of dark matter annihilation, and direct detection of dark matter in terrestrial labs. The founding principle of direct dark matter detection is that since dark matter is known to exist in the local universe, as the Earth, Solar System, and the Milky Way Galaxy carve out a path through the universe they must intercept dark matter, regardless of what form it takes. Direct detection of dark matter faces several practical challenges. The theoretical bounds for the supposed mass of dark matter are immense, spanning some 90 orders of magnitude from 10−21 eV to about that of a Solar Mass. The lower limit of dark matter is constrained by the knowledge that dark matter exists in dwarf galaxies. From this knowledge a lower constraint is put on the mass of dark matter, as any less massive dark matter would have a de Broglie wavelength too massive to fit inside observed dwarf galaxies. On the other end of the spectrum the upper limit of dark matter mass is constrained experimentally; gravitational microlensing using the Kepler telescope is done to detect MACHOs (MAssive Compact Halo Objects). Null results of this experiment exclude any dark matter candidate more massive than about a solar mass. As a result of this extremely vast parameter space, there exist a wide variety of proposed types of dark matter, in addition to a broad assortment of proposed experiments and methods to detect them. The spectrum of proposed dark matter matter mass is split into three broad, loosely defined categories as follows: In the range of zepto-electronvolts (zeV) to 1 eV theories predict a bosonic or field like dark matter. The primary dark matter candidate in the range are axions, or axion-like particles. From about 1 eV to the Planck Mass, dark matter is projected to be fermionic or particle-like. Favorites in this range include WIMPS, thermal relics, and sterile neutrinos. Finally, in the mass range between the Planck Mass to masses on the order of the Solar mass, dark matter would be a composite particle. The leading theory for composite dark matter are primordial black holes. (en)
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| rdfs:comment
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- Direct detection of dark matter is the science of attempting to directly measure dark matter collisions in Earth-based experiments. Modern astrophysical measurements, such as from the Cosmic Microwave Background, strongly indicate that 85% of the matter content of the universe is unaccounted for. Although the existence of dark matter is widely believed, what form it takes or its precise properties has never been determined. There are three main avenues of research to detect dark matter: attempts to make dark matter in accelerators, indirect detection of dark matter annihilation, and direct detection of dark matter in terrestrial labs. The founding principle of direct dark matter detection is that since dark matter is known to exist in the local universe, as the Earth, Solar System, and the (en)
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