BY: Nathan Schmidt Period: 5 Astronomy

A brief history of black holes About 2 centuries ago John Michel was the first person to suggest that it was possible for an object to have such a great gravitational pull that nothing not even light could escape it. He called them “dark stars.” But he was shot down by all the astronomers of his day and nobody believed him. In 1916 astrophysicist Karl Schwartzschild decided to compute the gravitational field of stars using Einsteins field equation. Although his predictions were not exact because he imputed that stars were perfectly spherical, gravitationally collapsed and did not rotate. The name “Black Hole” was not used until the 1960’s when physicist john wheeler named them that.

Think of space as like a blanket in which the universe sits on. All object lye on the space blanket and push down on it which bends space. So when you have two objects close enough they are both pushing don and making a dip in space that they slide together

This is a simulation of the black hole in front of the milky way it has 10 solar masses meaning that it has 10x the mass of the sun. This image also shows one of the extraordinary aspects of a black hole. Being that black holes are invisible.

Black holes are invisible due to the fact that the gravitational pull of a black hole is so great it actually pulls in light and doing so makes it so that it is invisible. You might ask, If black holes are invisible then why cant you see the stars behind them? The reason for that is because it pulls in the light from the stars behind it and from all directions so that the light does not reach our eyes. it is pulled into the center of the black hole and super compressed.

This image demonstrates two aspects of a black hole including the effect black holes have on nearby stars and the hawking radiation jets that shoot out the top and bottom of the black hole This image is of a binary star system one of the stars having become a black hole

Scientists are able to make microscpic black holes in a particle accelerator. Scientists have even transported photons of light hundreds of miles through black holes This is the fermilab particle accelerator, one of the largest in the world. this uses electrical fields to speed partcles at super speeds and smash them together and study the interior of those particles.

LOCATION Astronomers believe that black holes are found at the center of galaxies like at the center of the Milky way Some places that black holes may exist are: Andromeda M87 NGC 4261 Milky Way

LOCATION 2 Astronomers also believe that black holes may be located in binary star systems where one of the stars has collapsed and formed a black hole One such star system is the binary star system Cygnus X-1 By studying the visible star astronomers can see that the other star is far too massive to be a white dwarf or a neutron star so they are almost positive that it is a black hole

Jets of high energy particles that are caused when the intense magnetic field focuses the particles and shoots them out at the axis of rotation.

The accretion disc is a spiraling cloud of matter that is being pulled into the center of the black hole.

The core of the black hole is comprised of super condensed matter and can have several times the mass of the sun. The core is where all the matter in the accretion disc ends up it has such a powerful gravitational pull that even light cannot escape it.

The event horizon is where the gravitational pull of the black hole becomes great enough that it can pull in light and since nothing can go faster than the speed of light then nothing can escape the black hole beyond this point.

This is a picture of the night sky using x-ray vision and although you may think that those colorful dots are stars they are not in fact they are black holes in far distant galaxies. (In this image, blue represents high-energy x-rays, green medium energy, and red low energy.)

Astronomers at the Smithsonian center for astrophysicists are trying to make a log of all the black holes in the universe they have found around a thousand so far. They see them by searching for the x-ray jets that are given off by black holes as the bring in material Astronomers have also discovered by investigating black holes that it is not just the gravitation pull of the black hole that is pulling in material from space but it is also the magnetic field that helps to attract and blow the material in toward the center of the giant.

“Things already in a stable orbit tend to stay in a stable orbit. We call that angular momentum” When you have a close orbiting star to a black hole the matter from the star is pulled into the accretion disc but not streight into the center of the black hole which would be the fact if it was only gravity acting on the matter That’s why astronomers believe that magnetic friction is causing the matter to stay in the disc

References "A Brief History of Black Holes." 11/7/95. 7 May "Image:Black hole.jpg." 1/5/08. 7 May "The truth about black holes, location." unknown. 7 May "Full-energy collision images." 2/12/08. 7 May "Fast-Flying Black Hole Yields Clues to Supernova Origin." 08/18/02. 7 May "Space Time Travel." 04/22/08. 7 May 2008.

References 2 "unknown." unknown. 7 May "New Black Hole May Shatter Record." 8/1/07. 7 May "1,000 Black Holes Revealed in New Sky Survey." 03/13/07. 7 May "Magnetism, Not Just Gravity, Makes Black Holes Suck, Study Says." june, 21, May 2008.