Black Hole and its Latest Discovery

 By – Monodivya Dewan 

 For many years the term black hole has fascinated millions, so without any further due let us dig into this topic.

 The term black hole is of a very recent origin. It was coined in 1967 by an American astronomer John Wheeler as a graphic description of an idea that goes back at least two hundred years, to the time where the wave particle duality of quantum mechanics was bought into the lime light. 

• If the light is made up of wave it was not clear how it would respond to gravity 

• If the light is composed of particle, gravity might have an important effect.

 On this assumption, John Michell, a Cambridge don, pointed out that a star that was sufficiently massive and compact would have such a strong gravitational field that light could not escape. Michell suggested that there might be a large number of stars like this. Although we would not be able to see them. Such objects are what we now call black holes as they are black void in space.

 Black hole is surrounded by a mathematical surface called event horizon within which the escape velocity of a particle exceeds the speed of light to make the escape impossible. 

 The Einstein’s theory of general relativity shows that when a massive star dies, it leaves behind a small, dense remnant core and if the core’s mass is of three times the mass of the sun then the force of the gravity overwhelms all the other forces, producing black hole, Scientists cannot directly observe black hole, however it can be detected by studying their effect on the other matter nearby. For example, if a black hole passes through a cloud of inter stellar matter it will draw matter inward by the ;process called accretion. Similar process occurs if a normal star passes close to black hole. In such cases, the black hole can tear the star apart as it pulls it towards itself. As the attached matter accelerates and heats up it emits x-rays that radiates into space. It can be detected using satellites and telescopes in space. 

 Most black holes form from the remnants of a large star that dies in supernova explosion.

 DISCOVERIES:

 Recent discoveries offers some tantalizing evidence that black hole have a dramatic influence on the neighborhoods around them – emitting powerful gamma ray burst, devouring nearby stars and spurring the growth of new stars in some area while stalling it in others. 

• Currently, a light has been detected behind a black hole for the first time, fulfilling a prediction rooted in albert Einstein’s theory of general relativity. It was discovered by Stanford University astrophysicist Dan Wilkins and his colleagues by observing x-rays released by a super massive back hole, located at the Centre of the galaxy, i.e., 800 million light years from the earth. According to Wilkins, ”Any light that goes into that black hole does not come out, so we shouldn’t be able to see anything that is behind the black hole. The reason we can see tat is because that black hole is warping space, bending light and twisting magnetic field around itself.” 

• On March 9, 2021, astronomers have found super massive black hole with a jet detected in x-ray using NASA’s Chandra x-ray observatory. This black hole is located 12.7 billion light years away from the earth. Chandra data revealed that this jet extends for about 160,000 light years or longer than the entire span of milky way. This result may help to explain how the biggest black hole formed so quickly. 

• On February 11, 2021, using the NASA/ESA Hubble space Telescope, scientists found an evidence of a concentration of smaller black holes lurking at the heart if the globular cluster NGC 6397. This new data have led to the first measurement of the extent of collection of black holes in a core-collapsed globular cluster.