Divya Shree Nandini presents an overview of black holes, describing them as regions in space with a gravitational pull so strong that nothing can escape. She categorizes black holes into three types: stellar, supermassive, and miniature, and discusses their formation, characteristics, and effects on surrounding matter. The presentation also touches on the origin of black hole theories, their physical properties, and the concept of black holes potentially 'dying' through a process called Hawking radiation.

1. DIVYA SHREE NANDINI
BACHELOR OF LEGISLATIVE LAW
Shri Ramswaroop Memorial University

2. A LITTLE BIT ABOUT MYSELF
 Hi my name is Divya Shree
Nandini.
 Today I hope will be useful for
both you and me.
 Don’t afraid to ask me about
something you’re unsure of.
 You’ll have the opportunity to ask
me questions at the end of the
presentation.
 Enjoy the ride! (she sai  -

3. What is BLACK HOLE
 “A black hole is a great amount of matter
packed in a very small area. It is a place in
space which has such a big gravitational
field,that nothing,not even light can escape.
scientists can’t directly observe black holes,and
the only way to percieve them is by detecting
their effect on other matter nearby.”
 Black holes are the evolutionary endpoints of
stars at least 10 to 15 times as massive as the
Sun.

4. Types of BLACK HOLE
 “According to theory, there might be
three types of black holes: Stellar,
super massive, and miniature black
holes-depending on their mass.
These black holes would have
formed in different ways.”
 Stellar black holes: “Stellar
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.”

5. Super massive black holes: “These type of
black holes have event horizons as small as
atomic particles. These were created during
the Big bang. Miniature black holes were
created more than 10 billion years ago, and
they compressed into a really small point,
which later exploded and created a massive
explosion. We don’t know exactly how
super massive black holes form, but it’s
likely that they’re a by product of galaxy
formation.”
Miniature black holes: “No one has ever
discovered a miniature black holes,
which would have a mass much smaller
than that of our sun. But it’s possible
that miniature black holes could have
formed shortly after the “Big Bang”,
which is thought to have started the
universe 13.7 billion years ago.”

6. Parts of a BLACK HOLE
Event Horizon- The event horizon of a black
hole is a boundary in space-time where light
and matter can only enter the black hole.
Matter and light falling inwards pass the
event horizon and can only move towards the
center of black hole.
Ergosphere- The ergosphere is an ellipsoidal region
located just outside the black hole, such as the poles
which touch the event horizon. The ergosphere is a
region in which an effect known as frame-dragging
occurs, making it impossible for someone to stand still
within.

7. Accretion Disk- An accretion disk forms around
the black hole consisting of matter that forms an
Omni-directional cloud around the black hole.
Matter in the disk gradually falls into the black
hole and the accretion disk is visible as long as the
black hole has a continual source of matter.
Photon sphere- A photon sphere is a region where
photons are forced to travel in orbits around the
black hole due to the gravitational influence of the
black hole.
Singularity- The singularity is the center of the
black hole where space-time becomes infinitely
curved. The singularity is infinitely dense and
the laws of physics break down here as matter
reaches its presence.

8. Existence of BLACK HOLES?
Astronomers have found convincing
evidence for a super massive black
hole in the center of our own Milky
Way galaxy, the galaxy NGC 4258, the
giant elliptical galaxy M87, and several
others. Scientists verified the existence
of black holes by studying the speed of
the clouds of gas orbiting those
regions. In 1994, Hubble Space
Telescope measured the mass of an
unseen object at the center of M87.
Based on the motion of the material
whirling about the center, the object is
estimated to be about 3 billion times
the mass of our Sun and appears to be
concentrated into a space smaller than
our solar system.

9. When were BLACK HOLES first theorized?
 Using Newton’s Laws in the late 1790s, John
Michell of England and Pierre-Simon Laplace of
France independently suggested the existence of an
“invisible star”. Michell and Laplace calculated the
mass and size - which is now called the “event
horizon” – that an object needs in order to have an
escape velocity greater than the speed of light. In
1915, Einstein’s theory of general relativity
predicted the existence of black holes. In 1967 John
Wheeler, an American theoretical physicist, applied
the term “black hole” to these collapsed objects.

10. How does a star become a BLACK
HOLE?
 “Only stars with very large masses can become black
holes. Our Sun, for example, is not massive enough to
become a black hole. Four billion years from now when
the Sun runs out of the available nuclear fuel in its core,
our Sun will die a quiet death. Stars of this type and their
history as white dwarf stars.”
 “If a star is even more massive than the one that forms a
neutron star, it goes through the same process of creating
a supernova ,but the force of gravity is so great because of
the amount of mass involved, that the neutrons cannot halt
the collapse of the star which continues to be squeezed
into a smaller and smaller ”

11. What would happen if you fell into a
BLACK HOLE?
 “ After that, gravity will drag you toward
the singularity at the speed of light and
ultimately spaghettify you. No one
knows what happens beyond the event
horizon, and astrophysicists suspects
that the physics we understand here on
Earth breaks down inside of a black
hole.”
 “ If you find yourself stuck inside a
black hole, Stephen Hawking says not to
panic: You may die, but all traces of
your existence may not be lost forever.
Current science suggests that a black
hole’s gravity is so strong that absolutely
nothing – not even light - can escape
once inside.”

12. PHYSICAL PROPERTIES
 The Schwarzschild black hole, which has no
charge, or rotation, the simplest type of
black hole that exists.
 The Reissner – Nordstrom black hole, which
does not rotate, but which has electrical
charge.
 The Kerr – Newman black hole, which has
charge and rotates.
 The Kerr black hole, which rotates and does
not have charge inside.

13. WHITE HOLES AND WARM HOLES
White holes are not proved to exist. A black hole
is considered to be the exact opposite of a black
hole. It cannot absorb matter, It can only expulse
it. It is considered by some physicists to be the
mathematical answer to the general equations of
relativity.
If white holes actually existed, then, we
would also see the appearance of a
wormhole. A wormhole is the combination
of a black hole and a wormhole.
Wormholes would make matter enter
through the white hole, because as they are
too close to each other, spaghettification
would not happen.

14. How can we study BLACK HOLES?
 “ Scientists can’t directly observe black
holes with telescopes that detect x-rays,
light, or other forms of electromagnetic
radiation. We can, however, infer the
presence of black holes and study them by
detecting their effect on other matter nearby.
”

15. Can BLACK HOLE die?
 “ This is because the escape
velocity of a black hole is
greater than the speed of light.
… What follows is a discussion
on how black holes “die.”
Perhaps “evaporate” is a more
suitable word in this case. The
process by which black holes
evaporate is called Hawking
radiation, or sometimes,
Bekenstein-Hawking
radiation.”

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