Black Hole
Black holes are places where ordinary gravity has become so extreme that it overwhelms all
other forces in the Universe. Once inside, nothing can escape a black hole's gravity; not even
light.
A black hole is a mathematically defined region of space time exhibiting such a strong
gravitational pull that no imminent particle or electromagnetic radiation can escape from it.
The theory of general relativity predicts that a sufficiently compact mass will deform space time
to form a black hole. The boundary of the region from which no escape is possible is called the
event horizon.
Objects whose gravitational fields are too strong for light to escape were first considered in the
18th century by John Michell and Pierre-Simon Laplace. The first modern solution of general
relativity that would characterize a black hole was found by Karl Schwarzschild in 1916,
although its interpretation as a region of space from which nothing can escape was first
published by David Finkelstein in 1958.
One Star's End is a Black Hole's Beginning.
Black holes of stellar mass are expected to form when very massive stars collapse at the end of
their life cycle. After a black hole has formed, it can continue to grow by absorbing mass from
its surroundings. By absorbing other stars and merging with other black holes, supermassive
black holes of millions of solar masses (M☉) may form. There is general consensus that
supermassive black holes exist in the centers of most galaxies.
Despite its invisible interior, the presence of a black hole can be inferred through its interaction
with other matter and with electromagnetic radiation such as light. Matter falling onto a black
hole can form an accretion disk heated by friction, forming some of the brightest objects in the
universe. If there are other stars orbiting a black hole, their orbit can be used to determine its
mass and location. Such observations can be used to exclude possible alternatives (such as
neutron stars). In this way, astronomers have identified numerous stellar black hole candidates
in binary systems, and established that the core of the Milky Way contains a supermassive black
hole of about 4.3 million M☉.
Recent Discoveries
August 12, 2014 NuSTAR Sees Rare Blurring of Black Hole Light (Markarian 335)
July 2, 2014
Black Hole Fireworks in Nearby Galaxy (Messier 106)
Swiftly Moving Gas Streamer Eclipses Supermassive Black Hole
June 19, 2014
(NGC 5548)
June 3, 2014
Black Hole 'Batteries' Keep Blazers Going and Going
May 22, 2014
WISE Findings Poke Hole in Black Hole 'Doughnut' Theory
March 26, 2014 Search for Seeds of Black Holes
Direct Measurement of a Distant Black Hole's Spin (RX J1131March 5, 2014
1231)
January 23,
Extreme Power of Black Hole Revealed (RX J1532.9+3021)
2014
January 8, 2014 Death by Black Hole in Small Galaxy? (Abell 1795)
December 3,
Massive Black Hole Duo (WISE J233237.05-505643.5)
2013
November 26,
Do Black Holes Come in Size Medium?
2013
November 20,
New Evidence for a Jet from Milky Way's Black Hole
2013
November 13,
Black Hole Boasts Heavyweight Jets (4U1630-47)
2013
Astronomers think the object shown in this Chandra X-ray Observatory image (in box) may be
an elusive intermediate-mass black hole. Located about 32 million light-years from Earth in the
Messier 74 galaxy (M74), this object emits periodic bursts of x-rays at a rate that suggests it is
much larger than a stellar-mass black hole but significantly smaller than the supermassive black
holes found at the centers of galaxies. Very few of such middling black holes have been
discovered, and scientists aren't sure how they form.