A great presentation about black holes

1. Black Holes

2. INDEX
1.Introduction to Black Holes
2.What are Black Holes?
3.How are Black Holes created?
4.Types of Black Holes
5.Parts of Black Holes
6.spaguettification

3. 1.Introduction
The first time the idea of a black hole was
suggested was in the late 1790´s by John
Michell of England and Pierre-Simon
Laplace of France. They both proposed
the idea of the existence of an “invisible
star” by applying the first Newton Law.
They calculated its mass and size, which is
now called the “event horizon” that an
object would need in order to be faster
than even the speed of light.
Later, in 1915, Einstein predicted the
existence of black holes with his general
relativity theory. After that, in 1967, John
Wheeler, an American theoretical
physicist, applied the term of black holes
to what it means now.

4. 2.What are Black Holes?
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 perceive
them is by detecting their effect on other matter nearby. As the attracted
matter accelerates & heats up, it emits x-rays that radiate into space,
emitting powerful gamma rays bursts, which devour nearby stars.

5. 3.HOW ARE BLACK HOLES
CREATED
Stellar black holes: One way black
holes are created is from dying
stars. Inside a star, the nuclear fuel
of a star and its own gravity collide.
This creates stability, but when it
runs out of nuclear fuel, gravity
compresses the star. The outer
layers explode into a supernova,
and the centre implodes (collapses
inwardly). After that, a black hole is
created. This only occurs in big
stars, which are at least 10 times
bigger than the sun.

6. 4.TYPES OF BLACK HOLES
Miniature black holes: these type of black holes
have event horizons as small as atomic
particles. Physicists suggest that 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.
Supermassive black holes: fast-moving gas jets
and gravitational forces are equal to 10 billion
suns compressed together. These are what we
call supermassive black holes. Their event
horizon is an imaginary sphere around them
which nothing can escape. When matter enters
the black hole, it increases in size, reaching
other matter which it could not absorb before.

7. ACCORDING TO ITS PHYSICAL
PROPERTIES:
The shwarzschild 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.

8. WHITE HOLES and
WORMHOLES
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 black hole, and appear again through the white hole, because as
they are too close to each other, spaguettification would not happen.

9. 5.PARTS OF A BLACK HOLE:
The singularity: This is the part
of a black hole in which all the
mass of the black hole has been
compressed to a very small
space. As a result, the
Singularity has almost infinite
density.
The Event Horizon: This is the
part of the black hole where
nothing can get out. It is usually
defined as a big sphere that
surrounds the black hole, and
which absorbs any material
including light. Some theories say
that only radiation can escape this
area.

10. The Accretion Disk: This is a disk
that is composed by stellar
material, which goes around the
black hole, forming a spiral
The Ergosphere: If a black hole is
rotating, as it spins, its mass causes the
space and time to rotate around it

11. The Photon Sphere: the photon sphere is a
place in which gravity is so high that photons
have to travel around the black holes´ orbit. It
is the place in which light is forced to stay
inside the black hole.
The Schwarzschild Radius: This is the event
horizon´s radius. It is the radius at which the
escape velocity is equal to the speed of light.Is
the event’s horizon radius. Its formula is:
R=2GM/c2

12. Jets of Gas: In some black holes, there is
such high intensity that magnetic fields
are emitted perpendicular to the
accretion disk. Due to this, some
charged particles have to go around the
black hole, because it is in a magnetic
field

13. 6.spaghettification
In Astrophysics, this term refers to the effect a
black hole imposes on a body or matter. The
term was proposed by Stephen Hawkins in his
book “A Brief History of Time”, where he
compared this effect to spaghettis, saying that
you are stretched, and you turn so thin that
you break apart, and transform into matter.

14. Curious facts about black holes
1.They can explote (only the smaller ones)
2.They fire Intergalactic Death Rays
3.It is not their mass, it is their size what matters
4.Black holes disort Space-Time
5.Objects appear to ‘freeze’ near a Black Hole
6.Black Holes eventually evaporate over time

15. photos