BLACK HOLE MERGES WITH UNUSUAL COMPACT OBJECT

BLACK HOLE MERGES WITH UNUSUAL COMPACT OBJECT

LIGO Scientific and VIRGO Collaborations (LSC) have detected an unusual compact object whose mass falls in between that of a typical black hole a neutron star

Absence of accompanying electromagnetic signatures such as flashes of light are compatible with both 

Present merger detected on august 14, 2019, only posed a puzzled

Black hole is a region of spacetime where gravity is so strong that nothing—no particles or even electromagnetic radiation such as light—can escape from it

Black holes are commonly classified according to their mass, independent of angular momentum, J.

Theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole

Once a black hole has formed, it can continue to grow by absorbing additional matter. Black holes can also merge with other objects such as stars or even other black holes

Matter that falls onto a black hole can form an external accretion disk heated by friction, forming quasars

 

Rotating black holes are surrounded by a region of spacetime in which it is impossible to stand still, called the ergosphere

Objects and radiation can escape normally from the ergosphere

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 

Simplest static black holes have mass but neither electric charge nor angular momentum. These black holes are often referred to as Schwarzschild black holes after Karl Schwarzschild who discovered this solution in 1916

Solutions describing more general black holes also exist. Non-rotating charged black holes are described by the Reissner–Nordström metric, while the Kerr metric describes a non-charged rotating black hole

Most general stationary black hole solution known is the Kerr–Newman metric, which describes a black hole with both charge and angular momentum

In 1963, Roy Kerr found the exact solution for a rotating black hole. Two years later, Ezra Newman found the axisymmetric solution for a black hole that is both rotating and electrically charged

 

First strong candidate for a black hole, Cygnus X-1, was discovered in this way by Charles Thomas Bolton,Louise Webster and Paul Murdin in 1972

In 1974, Hawking predicted that black holes are not entirely black but emit small amounts of thermal radiation at a temperature ℏ c³/(8 π G M k_B); this effect has become known as Hawking radiation

If a black hole is very small, the radiation effects are expected to become very strong

On 11 February 2016, the LIGO Scientific Collaboration and the Virgo collaboration announced the first direct detection of gravitational waves, which also represented the first observation of a black hole merger

 

On 10 April 2019, the first ever direct image of a black hole and its vicinity was published, following observations made by the Event Horizon Telescope in 2017 of the supermassive black hole in Messier 87's galactic centre.