The Shiva hypothesis, also known as coherent
catastrophism, is the idea that global natural catastrophes on Earth, such as
extinction events, happen at regular intervals because of the periodic motion of the Sun in relation to the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
galaxy.
Initial proposal in 1979
William Napier and
Victor Clube
Stace Victor Murray Clube (born 22 October 1934 in London) is an English astrophysicist.
He was educated at St John's School, Leatherhead and Christ Church, Oxford. in He played first-class cricket for Oxford University. He appeared seventeen ...
in their 1979 ''
Nature
Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' article, ”A Theory of Terrestrial Catastrophism”, proposed the idea that gravitational disturbances caused by the
Solar System
The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
crossing the plane of the
Milky Way galaxy
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...
are enough to disturb
comets
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
in the
Oort cloud
The Oort cloud (), sometimes called the Öpik–Oort cloud, first described in 1950 by the Dutch astronomer Jan Oort, is a theoretical concept of a cloud of predominantly icy planetesimals proposed to surround the Sun at distances ranging from ...
surrounding the Solar System. This sends comets in towards the inner Solar System, which raises the chance of an impact. According to the hypothesis, this results in the Earth experiencing large impact events about every 30 million years (such as the
Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
).
Later work by Rampino
Starting in 1984,
Michael R. Rampino published followup research on the hypothesis. Certainly Rampino was aware of Napier and Clube's earlier publication, as Rampino and Stothers' letter to ''Nature'' in 1984 references it.
In the 1990s, Rampino and Bruce Haggerty renamed Napier and Clube's Theory of Terrestrial Catastrophism after
Shiva
Shiva (; sa, शिव, lit=The Auspicious One, Śiva ), also known as Mahadeva (; ɐɦaːd̪eːʋɐ, or Hara, is one of the principal deities of Hinduism. He is the Supreme Being in Shaivism, one of the major traditions within Hindu ...
, the Hindu god of destruction. In 2020, Rampino and colleagues published non-marine evidence corroborating previous marine evidence in support of the Shiva hypothesis.
Similar theories
The Sun's passage through the higher density spiral arms of the galaxy, rather than its passage through the plane of the galaxy, could hypothetically coincide with mass extinction on Earth.
However, a reanalysis of the effects of the Sun's transit through the spiral structure based on CO data has failed to find a correlation.
The Shiva Hypothesis may have inspired yet another theory: that a brown dwarf named
Nemesis causes extinctions every 26 million years, which varies slightly from 30 million years.
See also
*
Local Bubble
The Local Bubble, or Local Cavity, is a relative cavity in the interstellar medium (ISM) of the Orion Arm in the Milky Way. It contains the closest of celestial neighbours and among others, the Local Interstellar Cloud (which contains the Sol ...
*
Tyche (hypothetical planet)
References
{{reflist
External links
Napier and Clube's 1979 article "A Theory of Terrestrial Catastrophism" by Michael Paine
*
ttp://adsabs.harvard.edu/abs/1996EM%26P...72..441R The "Shiva Hypothesis": Impacts, Mass Extinctions, and the Galaxy by Rampino and Haggerty
The Shiva hypothesis: impacts, mass extinctions, and the Galaxy by Rampino, M. R.
The correlation between mas extinctions and impacts of near-Earth objects. The review of Shiva hypothesis by Yang Su, Yi Xia and Yanan Zhang.
Hypothetical impact events