Black Hole

 Black Hole  

What Is a Black Hole? 

    (source from Google)

A black hole is a region in space where the pulling force of gravity is so strong that light is not able to escape. This take place at the end of a star's life. Some black holes are a result of dying stars. As no light can escape, black holes are invisible. However, space telescopes with special instruments can help find black holes.

The boundary of the region from which no escape is possible is called the event horizon.

In many ways, a black hole acts like an ideal black body as it reflects no light.

How Do Black Holes Form?

Primordial Black holes are thought to have formed in the early universe, soon after the big bang. Black  holes form when the center of a very massive star collapses in upon itself. This  collapse also causes a supernova, or an exploding star, that blasts part of the star into  space. Scientists think super-massive black holes formed at the same time as the galaxy   they are in.       (source from Google)

Growth of Black Hole - 

Once a black hole has formed, it can continue to grow by absorbing additional matter. Any black hole will continuously absorb gas and interstellar dust from its surroundings. This is the primary process through which super-massive black holes seem to have grown. A similar process has been suggested for the formation of intermediate-mass black holes found in globular clusters. Black holes can also merge with other objects such as stars or even other black holes.      (source from Google)

First Image of a Black Hole -

  

(source from Google)

The Event Horizon Telescope (EHT) - a array of eight ground-based radio telescopes forged through international collaboration - was designed to capture images of a black hole. In coordinated press conferences across the globe, EHT researchers revealed that they succeeded, unveiling the first direct visual evidence of the super-massive black hole in the centre of Messier 87 and its shadow. 

The black hole’s boundary is around 2.5 times smaller than the shadow it casts and measures just under 40 billion km across.

Each telescope of the EHT produced enormous amounts of data - roughly 350 terabytes per day - which was stored on high-performance helium-filled hard drives. These data were flown to highly specialised supercomputers at the Max Planck Institute for Radio Astronomy and MIT Haystack Observatory to be combined. They were then converted into an image using novel computational tools developed by the collaboration.

The first ever image of a Black Hole was taken by the Event Horizon Telescope (EHT) . The super massive Black Hole is at the center of Messier 87, a massive galaxy in the constellation of Virgo. It is located 55 million light years from earth and has a mass of 6.5 billion times larger than our sun. 

If Black Holes Are "Black," How Do Scientists Know They Are There?

A black hole can not be seen because of the strong gravity  that is pulling all of the light into the black hole's center. However, scientists can see the effects of its strong gravity on the stars and gases around it. If a star is orbiting a certain point in space, scientists can study the star's motion to find out if it is orbiting a black hole. When a black hole and a star are orbiting close together, high-energy light is produced. Scientific instruments can see this high-energy light.                  (source from  NASA)

Could a Black Hole Destroy Earth?

Black holes do not wander around the universe. They follow the laws of gravity just like other objects in space. The orbit of a black hole would have to be very close to the solar system to affect Earth, which is not likely. If a black hole with the same mass as the sun were to replace the sun, Earth would not fall in. The black hole with the same mass as the sun would keep the same gravity as the sun. The planets would still orbit the black hole as they orbit the sun now.                  (source from NASA)

How Is NASA Studying Black Holes?

NASA is learning about black holes using spacecraft like the Chandra X-ray Observatory, the Swift satellite and the Fermi Gamma-ray Space Telescope. Fermi was launched in 2008 and is observing gamma rays - the most energetic form of light - in search of super-massive black holes and other astronomical phenomena.                                    (source from NASA)