Black Holes by Carlos Ruiz Aquino, Daniel Hirch Marina and Raul Diaz Gomez de 4º ESO grupo A

1. BLACK
HOLES Raúl Díaz Gómez
Daniel Hirsch Marina
Carlos Ruiz Aquino
4º ESO A

2. Definition
A black hole is a region of spacetime whose gravitational fields are too
strong for light and any mass known to escape.
Black holes don’t emit radiaton and light but the objects they absorb do,
thats why we can see are shiny.

3. Structure of Black Holes
• The Singularity: This is the region of the black hole where all the
mass of the black hole has been compressed down to nearly zero
volume. As a result the singularity has almost infinite density and
creates an enormous gravitational force.
• The Event Horizon: This is the "point of no return". Any object, even
light, that is within this radius cannot escape the gravitational pull of
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,
R = 2GM/c2

4. Structure of Black Holes
• The Accretion Disk: This is a
disk composed of stellar
material that is spiraling
towards that black hole
• The Ergosphere: If the black
hole is rotating, then as it spins,
its mass causes the space time
around the black hole to rotate
as well. This region is called
the ergosphere.
• Jets of Gas: For some black
holes high intensity magnetic
fields are emitted perpendicular
to the accretion disk. This
causes charged particles to
circle these magnetic field lines
and creates jets of gas
perpendicular to the
acceleration disk.

5. Theories
Most things known about black holes are only theories that are not true:
• The Einstein-Rosen Bridge Theory-> it says that if a human goes through a
black hole, he will be suck down in a tunnel and shot out in a “white hole”
in a parallel universe.
• Collapsed stars-> it says that black holes is simply a massive, dead star
whose gravity is so intense that even light cannot escape.

6. •Russian Dolls Universe Theory-> It says that the Universe is an infinite dark void with infinite
number of planets, stars, galaxies and intergalactic spaces floating inside and governed by the
same physical laws and constants. Like part of a cosmic Russian doll, our universe may be
nested inside a black hole that is itself part of a larger universe.
•How black holes are created-> A common type of black hole is produced by certain dying
stars. A star with a mass greater than about 20 times the mass of our Sun may produce a black
hole at the end of its life. But most of the stars cannot become a black hole because they don’t
have the mass to become it so when they die, they become white dwarf star which will sink
due to its own weight.

7. How to detect Black Holes
The black holes don’t emit electromagnetic radiaton so it’s quite difficult
to detect their effects. His gravitatory effects can be noticed in near
objects which movement is influenced by the black holes.
According to the relative theory, the light is deflected when it passes
near a massive object.

8. Sagitario A
It is the closest black hole to the Earth. Astronomers are confident that these observations of Sagittarius A*
provide good evidence that our own Milky Way galaxy has a supermassive black hole at its center.
In Chile, they show how the cloud is so hot that her front has already passed the point of maximum
approach and away from the black hole of more than ten million miles per hour, while the tail is still falling
towards him.

9. Sagitario A
Location
It is located at the center of the Milky Way.
Discovery
It was discovered on February 13th 1974 by the
astronomers Bruce Ballick and Robert Brown
using the interferometer of the National Radio
Astronomy Observatory.

10. Cygnus X-1
It is a well-known galactic X-ray source and black hole candidate in the constellation Cygnus. Cygnus X-1 was the
first and brightest source of x-rays discovered in Cygnus galaxy (X-rays are photons (particles of light) that
carry more energy than the light we see). It is now estimated to have a mass about 14.8 times the mass of the
Sun and has been shown that is too compact to be any known kind of normal star or other likely object besides a
black hole. If so, the radius of its event horizon is about 44 km.

11. Cygnus X-1
Location
It is located in the Cygnus Galaxy.
Discovery
It was discovered by the Uhuru satellite in 1791.