Detail about Black holes. It's definition, components and then history of black hole and General theory of relativity. Life cycle of a star and formation of black hole in space. Different types of choice after star's life end. Different types of Black hole on basis on mass of Parent star. and classification of black holes on basis of charge and rotational motion of black holes. Quantum theory of physics. Study of Black holes using Quantum mechanics by Steaphen Hawking. Current research on black holes.

1. Black Holes
Presented by:
Krunal Saija

2. Out-Lines
1. Introduction
2. Components of BH
3. History
4. Life Cycle of Stars
5. Formation of BH
6. Growth and Size
7. Classification
8. How do we find BH in Space ??
9. Open Questions (Current Researches)

3. What is a black hole ?
“A black hole is a region of space that is so
incredibly dense that not even light can
escape from it.”
“Black hole is a great amount of
matter packed into a very small area.”
1
2
Do not let the name fool you
Black hole is nothing but Empty Space.

4. Continue…
• Black holes don't have any greater gravitational force
than any other star of the same mass but it has higher
density.
• Mass is so great in such a small volume that the velocity
needed to escape is greater than the speed light travels.
• Though they are black they are invisible to us.
• Not tangible also.

5. EVENT HORIZON and SCHWARZSCHILD RADIUS
• Sensational Fact: If our sun suddenly became a black hole of
the same mass the rest of the objects, including Earth, would be
unaffected gravitationally. The Earth would remain in its current
orbit, as would the rest of the planets.

6. Sun is in its
original form
Sun convert into Black Hole
• No any effect to Earth
and any other planets.
• Of course other things
would be affected, such
as the amount of light
and heat that Earth
received.

7. Continue…
• The boundary of the region of black hole from which no escape is
possible is called the EVENT HORIZON.
• The center of the black hole is a point of infinite density and zero
volume, called a SINGULARITY.
• Event Horizon radius is known as Schwarzschild Radius.
• Objects start to travel at the speed of light after they reach the
INNER EVENT HORISON.
• For the simplest case (a non-rotating, charge neutral black hole).
The event horizon radius would be defined as
Rs = 2GM/c2
G=Gravitational Force ; M=Mass ; c=Velocity of light.

9. HISTORY OF BLACK HOLE
• In the 1783, John Michell and Pierre-Simon Laplace first
mentioned about the objects with a huge gravitation, from which
even light cannot escape.
• In 1915, Albert Einstein developed the theory of GENERAL
RELATIVITY. Which says that Gravity influence light motion.
• Karl Schwarzschild did find black holes as a solution to
Einstein’s equations by using Newton’s theory. (1916)
• Robert Oppenheimer and Hartland Snyder predict that
massive stars can collapse into black holes (1939)

10. LIFE CYCLE OF STARS
• In the normal life of a star there is a constant tug of war between
gravity pulling in and pressure pushing out.
• Thermo Nuclear reactions in the core of the star produce enough
energy and pressure to push outward.
• Gravity and pressure balance each other exactly, and so the star
is stable.
• However, when a star runs out of nuclear fuel, gravity gets the
upper hand and the material in the core is compressed even
further. The core matter is forced into an extremely dense state
and concentrate in very small volume.

12. DO ALL STARS BECOME BLACK HOLES?
It all depends on
the amount of
mass stars
contain
Mass < 1 sun
Mass ≈ 3 suns
Mass > 8 suns
Becomes
a Nebula Becomes
a Neutron star
Becomes
a Black Hole

13. FORMATION OF BLACK HOLE
One Star's End is a Black Hole's Beginning
• The most common way for a black hole to form is probably
in a supernova, an exploding star.
• Astronomers suspect that most black holes are produced when
massive stars (at least 8-10 times the Sun's mass) reach the end
of their lifecycle.
• Start that has 8 to 20 times the mass of our Sun converted in to
Stellar Mass Black Hole.
• Start that has million times the mass of our Sun converted in to
Supermassive Black Hole.

14. Mid Mass Supermassive Stellar mass

15. Growth of Black Hole
• Once a black hole has formed, it can continue to grow by
absorbing additional matter. Any black hole will continually
absorb gas and interstellar dust from its direct surroundings
and omit present cosmic background radiation.
• Another possibility is for a black hole to merge with other
objects such as stars or even other black holes

16. Size of black holes
• Black holes are available in variety of size.
• Smallest Black hole’s size is equal to atom size of Helium.
But it contains thousand times more mass than sun.
• A typical 10-solar-mass black hole would have a radius of
30 kilometers.

17. 17
on the basis of CHARGE and motion :
FOUR types of black holes
• Schwarzchild black holes :
Don’t rotate and have NO charge.
• Reissner – Nordstrom black holes :
Don’t rotate but have charge.
• Kerr black holes :
Rotate but have NO charge.
• Kerr - Newman black holes :
Rotate and have charge.

18. How do we find BH in Space ?
• Nobody has literally seen a black hole yet, but there are some
methods and instruments with which astronomers detect and
study BH.
• Actually we cannot find exact location of BH.
Methods:
• Predict using various equations like space-time gravity (given by
Einstein in GTR) and Schrodinger’s equation.
• Binary X-ray sources are placed to find strong black hole .
• Continuous fluctuation and Sudden change in gravity.

19. Some important terms
• Physical Information : In Physics, Physical Information refers
generally to the information that is contained in a physical
system in wave form. That is, all of its properties, all that makes
it distinct from other things. It is a complete description of the
thing, but in a sense that is divorced from any particular
language.
Example: Mass, KE, PE, Momentum etc…
• General Theory of Relativity [ GR ]
• Quantum Theory of Physics [ QT ]

20. Open questions on bh (GR v/s qt)
• In 1974, using Quantum Theory of Physics, Stephen
Hawking told that BH produces Radiation named as
Hawking Radiation. He is the first who had started
analyzing BH using QT and gave some controversy.
• Theory of GR strictly says that, any matter (even light)
cannot escape from BH BUT in 2004, Hawking told that
Physical Information can run off from BH, with this some
energy also release from it which make Firewall above
Event Horizon which is known as INFORMATION
PARDOX.

21. Continue…
• This fact is totally opposite to General Theory of Relativity.
According to Theory of relativity there is no any other
things or information above Event Horizon.
• Researchers follow QT believe that we are able to get
some information which is available on Information Pardox
and get knowledge about BH.
• In Modern approach of Physics, both of theories are used
to solved this type of labyrinthine problems.

22. Reference
• http://en.wikipedia.org/wiki/Black_hole
• http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.
html
• http://science.nationalgeographic.com/science/space/universe/black-holes-article/
• http://www.space.com/15421-black-holes-facts-formation-discovery-sdcmp.
html
• http://www.youtube.com/watch?v=bLTDjsvjnCA
• http://www.discovery.com/tv-shows/other-shows/videos/how-the-universe-works-
birth-of-a-black-hole.htm