BLACK

HOLES Raúl Díaz Gómez

Daniel Hirsch Marina

Carlos Ruiz Aquino

4º ESO A

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.

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

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.

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.

•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.

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.

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.

Sagitario ALocation 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.

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.

Cygnus X-1

Location

It is located in the Cygnus Galaxy.

Discovery

It was discovered by the Uhuru satellite in 1791.