Black Hole

This article is all about black holes.This articles gives you information about a black hole and is written with keeping in mind the latest image that has been captured by the scientists of a black hole.But What is a Black hole?A Black hole is a region of spafcetime possessing such strong gravitational effects that even particles and electromagnetic radiations such as light cannot escape from inside it.A Black hole acts like a black body as it not reflects light.The idea of a black hole was first given by John Michell in a letter published in November 1784.His calculations assumed that such a body might have the same density as the Sun and concluded that such a body will be formed when a star’s diameter exceeds the Sun’s by a factor of 500 and the surface escape velocity exceeds the speed of light.

In 2017 a number of institutions around the world jointly decided to pool the scanning abilities of eight telescopes from Hawaii to the South Pole and focus on getting a picture of a black hole.On April 10 astronomers shared an image as a giant meduvada in the sky from the black hole at Messier 87 or M87.The image seemed to be a blurred,yellowish orange frame surrounding a black centre.The black hole measures 40 billion km across three million times the size of the Earth and is 55 trillion light years away from earth.One light year is about 9.46 trillion km.The image of the black hole has been analysed in six studies coauthorised by 200 experts from 60 odd institutions and published on Wednesday in Astrophysical Journal Letters.

The astronomers used a technique known as interferometry which combines radiation from eight telescopes from around the world in a way that it appears as one single telescope capture.This virtual telescope would capture traces of electormagenetic radiations from jets of particles spewed from the event horizons of the black hole.The EHT team observed M87 and Sagittarius A(Sgr A), the black hole at the centre of our Milky Way over five nights in April 2017,using 8 radio telescopes that are sensitive to the wavelength of a millimetre.The telescope used by them were stretched from Hawaii to Arizona,Mexico to Spain and Chile to South Pole.The data was generated was voluminous and could not be transferred on Internet so was recorded on disk and Shipped to MIT Boston.It took a year to transfer from South Pole due to bad weather. A total of 4 petabytes were recorded the equivalent of 8000 years of MP3 format music played non stop and was crunched in supercomputers by teams of scientists.A report in Science said that four independent teams duplicated the data processing to eliminate biases and over four days of observation of M87.The image from Sagittarius A(Sgr A) was not selected as image of M87 was better.This is a great achievement in the field of astronomy for the scientists.