SuperFast Guide to Black Holes
Quick and easy summaries of relativity and related subjects
Black holes are among the most mysterious and intriguing objects in the universe.
They are regions of spacetime where gravity is so strong that nothing, not even light,
can escape. This intense gravitational pull is due to the extremely dense concentration
of matter packed into a very tiny space.
Black holes are formed by the death of a massive star. When such a star has finally
used up all of its internal thermonuclear fuels at the end of its life, the core becomes
unstable and gravitationally collapses inward upon itself. The star’s outer layers are
blown away, forming a supernova, and the crushing weight of the constituent matter
falling in from all sides compresses the dying star to a point of zero volume and infinite
density called a singularity.
The boundary of no escape from a black hole is known as the event horizon. Inside the
event horizon, the escape velocity exceeds the speed of light, so that not even rays of
light can escape into space. The radius of the event horizon is called the
Schwarzschild radius, named after the German astronomer Karl Schwarzschild, who
predicted the existence of collapsed stellar bodies that emit no radiation.
There is much we don’t know about black holes, such as what matter looks like inside
their event horizons. However, scientists primarily detect and study them based on
how they affect their surroundings. For example, black holes can be surrounded by
rings of gas and dust, called accretion disks, that emit light that can be detected across
many wavelengths, including X-rays.
Black holes vary greatly in size and mass:
The smallest known black hole is only 3.8 times the Sun’s mass.
The most massive observed, TON 618, tips the scales at 66 billion
times the Sun’s mass.
Most Milky Way-sized galaxies, including our own, have supermassive black holes at
their centers.
In summary: black holes are regions in space where gravity is so strong that nothing,
not even light, can escape, and they are formed from the remnants of massive stars.
Suggested further reading:
Energy from nuclear fusion - From stars to black holes
General Relativity - How gravitation causes black holes when stars collapse
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SuperFast Guide to
Black Holes
[ Special Relativity ] [ General Relativity ] [ Einstein ] [ Time Dilation ]
[ Black Holes ] [ Twin Paradox ] [ Time Dilation Formula ]
[ Special Relativity ] [ General Relativity ] [ Einstein ] [ Time Dilation ]
[ Black Holes ] [ Twin Paradox ] [ Time Dilation Formula ]
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Quick and easy summaries of relativity and related subjects
SuperFast Guide to Black Holes
Black holes are among the most mysterious and intriguing objects
in the universe. They are regions of spacetime where gravity is so
strong that nothing, not even light, can escape. This intense
gravitational pull is due to the extremely dense concentration of
matter packed into a very tiny space.
Black holes are formed by the death of a massive star. When
such a star has finally used up all of its internal thermonuclear
fuels at the end of its life, the core becomes unstable and
gravitationally collapses inward upon itself. The star’s outer layers
are blown away, forming a supernova, and the crushing weight of
the constituent matter falling in from all sides compresses the
dying star to a point of zero volume and infinite density called a
singularity.
The boundary of no escape from a black hole is known as the
event horizon. Inside the event horizon, the escape velocity
exceeds the speed of light, so that not even rays of light can
escape into space. The radius of the event horizon is called the
Schwarzschild radius, named after the German astronomer Karl
Schwarzschild, who predicted the existence of collapsed stellar
bodies that emit no radiation.
There is much we don’t know about black holes, such as what
matter looks like inside their event horizons. However, scientists
primarily detect and study them based on how they affect their
surroundings. For example, black holes can be surrounded by
rings of gas and dust, called accretion disks, that emit light that
can be detected across many wavelengths, including X-rays.
Black holes vary greatly in size and mass:
The smallest known black hole is only 3.8 times the Sun’s
mass.
The most massive observed, TON 618, tips the scales at
66 billion times the Sun’s mass.
Most Milky Way-sized galaxies, including our own, have
supermassive black holes at their centers.
In summary: black holes are regions in space where gravity is
so strong that nothing, not even light, can escape, and they are
formed from the remnants of massive stars.
Suggested further reading:
Energy from nuclear fusion - From stars to black holes
General Relativity - How gravitation causes black holes
when stars collapse
[ Special Relativity ] [ General Relativity ] [ Einstein ]
[ Time Dilation ] [ Black Holes ] [ Twin Paradox ]
[ Special Relativity ] [ General Relativity ] [ Einstein ]
[ Time Dilation ] [ Black Holes ] [ Twin Paradox ]
