Briefing About BLACKHOLE with full details

Discovering : BLACK HOLE

What are Black Holes ?

Black Holes are some of the strangest and most fascinating objects found in outer space . They are the objects of extreme density , with such strong gravitational attraction that even light cannot escape froem their grasp if it comes near enough . 

Albert Einstein first predicted Black Holes in 1916 with his general theory of relativity . The term " Black Hole " was coined in 1967 by American Astronomer John Wheeler , and the first one was discovered in 1971. 

There are three types of Black Holes : Stellar Black Holes , Supermassive Black Holes and Intermediate Black Holes . 

On April 10 , 2019 , a team of 200 astronomers created history after they released the first ever images of a Black Hole . Dr Katherine Bouman ,  a 29-year-old Post-Doctoral fellow at MIT was lauded across the world for being instrumental in the creation of the algorithm that help produce this image . 

What's the deal with the Black Holes ?

A Black Hole is a mysterious place in space with such enormous mass and extreme gravity that nothing can escape it . Not even light . As light does not get out , Black Holes are invisible .

Black Holes emerge from Einstein's theory of general relativity , with names of eminent physicists like Karl Schwarzschild and David Finkelstein attached to their detection . While several artists have tried to create images of what these cosmic sinkholes look like , this is the first visual evidence of a supermassive Black Hole . 

Located at the center of the Messier 87 galaxy , it is 500 million trillion km away from the Earth and is 3.3 Million times the size of earth !

What did the image show ?

The image reveals a ring - like structure with a dark centre.  This ring-like boundary is termed as the event horizon . It is 2.5 times smaller than the shadow it casts and measures 40 billion km across . 

Event Horizon is the region around the centre of the Black Hole from where no matter and energy can escape . It is also known as the " point of no return " the shadow of the Messier 87 Black Hole is being called supermassive . Why ? It has a mass of about 6.5 billion times the mass of the Sun ! 

How did the Astronomers capture the Image ?

The team of 200 astronomers created a network of ten radio telescopes which were synchronized by technology , so as to function as an Earth - sized virtual observatory called the Event Horizon Telescope ( EHT ) .

Because of its very large wavelength , the size of a radio telescope to resolve such a tiny angular structure should be extremely large , effectively of the order of 5000 kilo meters , and such a huge single telescope is impossible to construct . Scientists , however , created an effective earth sized telescope by using an array of radio telescopes located at various sites of the Earth . 

The EHT network telescopes in Hawaii , Mexico , Spain , Chile , and Antarctica exploited the Earth's rotation to serve as a single giant telescope that can discern regions of space just 15 to 20 micro-arcseconds , the equivalent of trying to spot  a golf ball on the moon . 

Here's a video : 

What is a Black Hole ?

A Black Hole is a place in space where gravity pulls so much that even light can not get out . The gravity is so strong because the matter has been squeezed into a tiny space . This can happen when a star is dying . 

Because no light can get out , people cant see Black Holes . They are invisible therefore Space telescopes with special tools can help find Black Holes . The special tools can see how stars that are very close to Black Holes act differently than other stars . 

How Big are Black Holes ? 

Black Holes can be big or small . Scientists think the smallest Black Holes are as small as just one atom. These Black Holes are very tiny but have the mass of a large mountain . Mass is the amount of matter , or " stuff " , in an object . 

Another kind of Black hole is called " stellar " . It's mass can be up to 20 times more than the mass of the sun . There may be many , many stellar mass Black Holes in Earth's galaxy . Earth's Galaxy is called the Milky Way . 

The largest Black Holes are called " supermassive " . These Black Holes have the masses that are more than 1 million suns together . Scientists have found proof that every large galaxy contains a supermassive  Black Hole at its center . The supermassive Black Hole at the center of the Milky Way galaxy is called Sagittarius A . It has a mass equal to about 4 million suns and would fit inside a very large ball that could hold a few million Earths . 

How Do Black Holes Form ? 

Scientists think that the smallest Black Hole is formed when the universe began . Stellar Black Holes are made when the center if a very big star falls in upon itself or collapses . When this happens , it causes supernova . A supernova  is an exploding star that blasts part of the stars in to the space . 

A Black Hole forms when any object reaches a certain critical density , and its gravity causes it to  collapse to an almost infinitely small pin point  . Stellar-mass Black holes form when a massive star can no longer produce energy in its core . The star's outer layers may blast away into the space , or they may fall into the Black Holes or to make it heavier . Astronomers aren't certain that how supermassive Black Holes form . They may form from the collapse of large clouds of gas or from the mergers  of many smaller Black Holes  , or a combination of events .

Interesting Fact About  Black Holes ?

 

 1 .  The force of gravity is so high in Black Holes that leads to Gravitational Time Dilation ( slowing down of the time) . Now the interesting thing is that the time dilation can also occur when velocity increases . Thus , time completely stops at the center of the Black Hole .

2 .  Black Holes have something known as Event Horizon ( point of no return ) . Now every Black Hole has its own boundary and any object outside the boundary is perfectly safe . But if , an object crosses the event horizon , then it will have no other option but to fall into the Black Hole . Once sucked in , that object can never reappear . 

3 . Black Holes are literally the densest object to live in universe . Now there's a question that " How dense can a Black Hole get ? " then the answer would be " Imagine what kind of density you will get if you try to squeeze in the entire mass of the Earth in an extremely small sphere with a DIAMETER of 9 millimetres ! " and that's the type of density Of which I am talking about .

4. Black Holes can keep growing because anything ( gas ' liquid or solid matters ) that enters the event horizon ( point of no return )  gets sucked in  . Thus , the Black Holes can grow infinitely large and they are known as supermassive Black Holes . 

5 . Stephen hawking theorized that the mass of the Black holes emit Radiation . According to him Black Holes keep losing their mass in the form of Radiation and eventually they evaporates .

6 . Black Holes eventually shrink down to the smaller than the size of an electron ( a sub-atomic particle ) . At this stage it reaches to a size that is known as " Planck Length " . This length actually the quantum size limit . Theoretically nothing cab be as smaller than this and there is actually no instrument available to measure the Planck length ( value of the Planck Length is 1.61619926 * 10-35 meters ) . 

7 . The Event Horizon is just the beginning of the Black Hole . It is not the core of the Black Hole . The core of the Black Hole is known as " Singularity " and this point is known as the ultimate destruction point which means that absolutely nothing can survive at this point . 

8 . Closer to a Black Hole , things simply gets distorted ( pulled in to it ) . The immense gravitational pull of the Black Holes have the ability to distort even space . This distortion gets profound because Black Holes spin rapidly .

9 . Stars spin and they continue doing so even after their death . this means they keep spinning even when they become Black Holes and these Black Holes keep turning faster as they keep evaporating and eventually shrink to Planck Length hence , along with this spin and their gravitational force , they distort everything around them . 

10 . Only if something that's travels faster than light can actually escape Black Hole , but unfortunately there is no such thing known to mankind until now.