Black holes cannot be seen as they don't reflect any light.

The centre of black hole is called singularity - a point of infinite density i.e the space curvature extends to infinity.

• if you take pressure out of the calculation,a uniform spherically symmetric star would contract to a single point of infinite density,I.e,Singularity.
• A singularity is what you end up with when a giant star is compressed to an unimaginably small point.
• It refers not...

• All the black hole will remember is the total mass, the state of rotation and the electric charge.
• A black hole has a boundary, called the event horizon. This is where gravity is just strong enough to drag light back and prevent it escaping.
• Because nothing can travel faster...

• During most of the life of a normal star, over many billions of years, it will support itself against its own gravity by thermal pressure, caused by nuclear processes which convert hydrogen into helium.
• The explosive force of nuclear fusion inside them creates outward pressure which ...

• But scientists know they exist because they rip apart stars that get too close to them and because they can send tremors through space.
• It was a collision between two black holes more than a billion years ago that triggered what are called ‘gravitational waves’.