Black Holes & Wormholes - New Documentary
Δημοσιεύτηκε στις 30 Ιουλ 2015
Black Holes & Wormholes - New Documentary
Black
holes are a phenomenon predicted by Albert Einstein's General Theory of
Relativity, which was published in 1916. In fact, the idea of a black
hole was proposed as early as 1783 by the amateur British astronomer
John Michell (and independently by the Frenchman Pierre-Simon Laplace in
1795).
Ironically, Einstein himself did not believe in the
existence of black holes, and he strongly resisted the idea, even though
his own theory predicted them. The general scientific consensus is now
that black holes do in fact exist, and that they are actually one of the
most important features of our universe. Astronomers have detected them
indirectly in enough different ways that there is little doubt of their
existence.
A black hole (the phrase is usually credited to the
American physicist John Wheeler in 1967, and is certainly a distinct
improvement on the original label of “gravitationally completely
collapsed objects”) is a region of space in which the gravitational
field is so powerful that nothing, including electromagnetic radiation
such as visible light, can escape its pull - a kind of bottomless pit in
space-time.
Artist's impression of a star torn apart by the gravity of a black hole - click for larger version
(Click for a larger version)
Artist's impression of a star torn apart by the gravity of a black hole
(Source: Chandra X-Ray Observatory: http://chandra.harvard.edu/resources/
illustrations/blackholes2.html)
At
its centre lies an infinitely small, infinitely dense singularity, a
place where the normal laws of physics break down. As the comedian
Steven Wright once remarked: “Black holes are where God divided by
zero”.
Einstein’s work was also at the heart of the theory of
wormholes, or “bridges” as he called them. The idea of a hypothetical
topological feature of space-time that is essentially a short-cut
through space and time, potentially linking widely separated parts of
the universe (or even different universes), has been understandably much
loved by science fiction writers over the years, although there is also
much theoretical work to support them.
To better understand how
black holes might be formed, a little background knowledge of the life
cycle of stars is useful (which will be covered in the following
section), as well as an understanding of general relativity and curved
space-time (which is a separate topic in its own right).
Black
holes are a phenomenon predicted by Albert Einstein's General Theory of
Relativity, which was published in 1916. In fact, the idea of a black
hole was proposed as early as 1783 by the amateur British astronomer
John Michell (and independently by the Frenchman Pierre-Simon Laplace in
1795).
Ironically, Einstein himself did not believe in the
existence of black holes, and he strongly resisted the idea, even though
his own theory predicted them. The general scientific consensus is now
that black holes do in fact exist, and that they are actually one of the
most important features of our universe. Astronomers have detected them
indirectly in enough different ways that there is little doubt of their
existence.
A black hole (the phrase is usually credited to the
American physicist John Wheeler in 1967, and is certainly a distinct
improvement on the original label of “gravitationally completely
collapsed objects”) is a region of space in which the gravitational
field is so powerful that nothing, including electromagnetic radiation
such as visible light, can escape its pull - a kind of bottomless pit in
space-time.
Artist's impression of a star torn apart by the gravity of a black hole - click for larger version
(Click for a larger version)
Artist's impression of a star torn apart by the gravity of a black hole
(Source: Chandra X-Ray Observatory: http://chandra.harvard.edu/resources/
illustrations/blackholes2.html)
At
its centre lies an infinitely small, infinitely dense singularity, a
place where the normal laws of physics break down. As the comedian
Steven Wright once remarked: “Black holes are where God divided by
zero”.
Einstein’s work was also at the heart of the theory of
wormholes, or “bridges” as he called them. The idea of a hypothetical
topological feature of space-time that is essentially a short-cut
through space and time, potentially linking widely separated parts of
the universe (or even different universes), has been understandably much
loved by science fiction writers over the years, although there is also
much theoretical work to support them.
To better understand how
black holes might be formed, a little background knowledge of the life
cycle of stars is useful (which will be covered in the following
section), as well as an understanding of general relativity and curved
space-time (which is a separate topic in its own right).
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