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Dark matter Reference Libraries

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Massive Compact Halo Object MACHO
2004-10-19 04:45:41

Massive Compact Halo Object (MACHO) -- Massive compact halo objects, or MACHOs, are a type of astronomical body proposed as one possible explanation for the presence of dark matter in galactic halos. A MACHO is a small chunk of normal baryonic matter, far smaller than a star, which drifts through interstellar space unassociated with any solar system. Since MACHOs would not emit any light of...

Galaxy
2004-10-19 04:45:41

Galaxy -- Stars are almost always found in collections called galaxies, together with gas, dust, and large amounts of dark matter detected by its gravitational effects. These are all held together by gravitational attraction and orbit a common centre. There is some evidence that black holes may exist at the centre of some or most galaxies. Galaxies come in three main types: ellipticals,...

Brown Dwarf
2004-10-19 04:45:40

Brown Dwarf -- Brown dwarfs are a special type of low-mass star (approximately 13-70 Jupiter masses) that do not have nuclear fusion occurring in their cores during their time on the main sequence. Early in their development most brown dwarf stars do have lithium fusion in their cores, and a lack of lithium is a test for low-mass objects that are suspected of being brown dwarfs. Many brown...

Word of the Day
negawatt
  • A unit of saved energy.
Coined by Amory Lovins, chairman of the Rocky Mountain Institute as a contraction of negative watt on the model of similar compounds like megawatt.