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Baryonic Dark Matter
In astronomy and cosmology, baryonic dark matter is dark matter composed of baryons. Only a small proportion of the dark matter in the universe is likely to be baryonic. Characteristics As "dark matter", baryonic dark matter is undetectable by its emitted radiation, but its presence can be inferred from gravitational effects on visible matter. This form of dark matter is composed of "baryons", heavy subatomic particles such as protons and neutrons and combinations of these, including non-emitting ordinary atoms. Presence Baryonic dark matter may occur in non-luminous gas or in Massive Astrophysical Compact Halo Objects (MACHOs) – condensed objects such as black holes, neutron stars, white dwarfs, very faint stars, or non-luminous objects like planets and brown dwarfs. Estimates of quantity The total amount of baryonic dark matter can be inferred from models of Big Bang nucleosynthesis, and observations of the cosmic microwave background. Both indicate that the amount of b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 1689
Abell 1689 is a galaxy cluster in the constellation Virgo (constellation), Virgo over 2.3 billion light-years away. Details Abell 1689 is one of the biggest and most massive galaxy clusters known and acts as a gravitational lens, distorting the images of galaxies that lie behind it. It has the largest system of gravitational arcs ever found. Abell 1689 shows over 160,000 globular clusters, the largest population ever found. There is evidence of merging and gases in excess of 100 million degrees. The very large mass of this cluster makes it useful for the study of dark matter and gravitational lensing. At the time of its discovery in 2008, one of the lensed galaxies, A1689-zD1, was the most List of the most distant astronomical objects, distant galaxy found. Gallery File:Gravitationell-lins-4.jpg, Yellow galaxies belong to the cluster itself. Red and blue are background galaxies gravitational lens, gravitationally lensed. File:Abell 1689.jpg, Mass map of Abell 1689. File:Glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
