The presentation discusses black holes, defined as regions in space with gravity so strong that not even light can escape. It covers their history, parts (singularity, outer event horizon, inner event horizon), and classifications (stellar-mass, supermassive, mid-mass) along with details about the closest and largest known black holes. The closest known black holes are several thousand light-years away, and the largest known black hole is in the galaxy M87, with a mass 6.6 billion times that of the sun.

1. Presentation
On
BLACK HOLES

2. Contents
• Introduction
• History
• Parts of Black Hole
• Classification
• Closest Black Hole
• Largest Black Hole

3. What is Black Hole?
An unimaginably dense region of space where space is curved
around it so completely and gravity becomes so strong that
nothing, not even light, can escape.
Mass is so great in such a small volume that the velocity needed
to escape is greater than the speed light travels.

4. History
The idea of black holes was rediscovered in 1916,
after Einstein published his theory of gravity. Karl
Schwarzschild then solved Einstein's equations for the
case of a black hole, which he envisioned as a spherical
volume of warped space surrounding a concentrated
mass and completely invisible to the outside world.

5. Parts of a Black Hole
There are three main parts to a black hole.
 Singularity
 Outer Event Horizon
 Inner Event Horizon
 The Singularity is the very center of a black hole. It is where the gravity is the strongest.
Singularity is just a big word that means "squashed up star".
 The Outer Event Horizon is the very outer layer. You would still be able to escape from a
black hole's gravity because the gravity on this layer is not as strong as the middle or center
layer.
 The Inner Event Horizon is the middle layer. This layer's gravity is strong. If it captures you,
then you can't escape. The gravity on this layer releases anything that it captures. It would
push you toward the center of a black hole where the gravity is very strong.

6. Classification of Black Holes
 Three classifications of black holes:
 Stellar-mass: 3 to 20 times the mass of our Sun
 Supermassive: Black holes with millions to billions of times the mass of
our Sun
 Mid-mass: In between stellar-mass and supermassive

7. Stellar-mass:
Black holes are made when a giant star, many times the mass of our Sun, dies.
Most of the star’s atmosphere is blown into space as a supernova explosion.
The star’s spent core collapses under its own weight.
If the remaining mass is more than the mass of 3 Suns, it will collapse into a black hole

8. Supermassive:
Extremely massive black holes have been found in the
centers of many galaxies - including our own!

9. Mid-Mass:
Scientists are finding these in the centers of large, dense star
clusters.
Like this globular star cluster, called M15, in our Galaxy.

10. Closest known of Black Hole
The closest black holes yet discovered are several thousand
light-years away. They are so far that they have no effect
on Earth or its environment. A supermassive black hole appears
to inhabit the center of the Milky Way galaxy, about 27,000
light-years away.

11. Largest Black Hole known till date
The largest of the nearby galaxies, M87, now has the largest
known black hole. It contains 6.6 billion times the mass of our
sun and could swallow our solar system whole.

12. Thank You…!