Nemesis (hypothetical star): Difference between revisions
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'''Nemesis''' is the name given to a hypothetical [[red dwarf star]], [[magnitude]] between 7 and 12, orbiting the [[Sun]] at a distance of about [[1 E15 m|50,000]] to [[1 E16 m|100,000]] [[astronomical unit|AU]], somewhat beyond the [[Oort cloud]]. |
'''Nemesis''' is the name given to a hypothetical [[red dwarf star]], [[apparent magnitude|magnitude]] between 7 and 12, orbiting the [[Sun]] at a distance of about [[1 E15 m|50,000]] to [[1 E16 m|100,000]] [[astronomical unit|AU]], somewhat beyond the [[Oort cloud]]. |
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Nemesis' existence was proposed by [[Richard A. Muller]] in 1984 (''Nature, vol 308, pp 715-717, 1984'') to explain an apparent 26-million year cycle in the occurrence of [[mass extinction|mass extinctions]] on [[Earth]] as noted by Raup and [[Jack Sepkoski|Sepkoski]]. |
Nemesis' existence was proposed by [[Richard A. Muller]] in 1984 (''Nature, vol 308, pp 715-717, 1984'') to explain an apparent 26-million year cycle in the occurrence of [[mass extinction|mass extinctions]] on [[Earth]] as noted by Raup and [[Jack Sepkoski|Sepkoski]]. |
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Revision as of 05:41, 18 March 2005
Nemesis is the name given to a hypothetical red dwarf star, magnitude between 7 and 12, orbiting the Sun at a distance of about 50,000 to 100,000 AU, somewhat beyond the Oort cloud.
Nemesis' existence was proposed by Richard A. Muller in 1984 (Nature, vol 308, pp 715-717, 1984) to explain an apparent 26-million year cycle in the occurrence of mass extinctions on Earth as noted by Raup and Sepkoski.
According to the theory, Nemesis periodically (roughly every 26 million years), passes through a denser region of the Oort cloud, disrupting the orbits of comets, and sending millions into the inner solar system and potential collision with the Earth.
No direct evidence for Nemesis has been found, however, and the existence of a periodicity in the Earth's series of mass extinctions is disputed.
See also
- End of Civilization
- Nemesis, a novel by Isaac Asimov about a fictional star of the same name
External links
- Richard A. Muller´s Nemesis Theory
- Nemesis: Does the Sun Have a 'Companion'? (Space.com, 03 April 2001)
- Exit Mundi, Nemesis an End-Of-World scenario.