Black Holes l

Black Holes

http://www.nasa.gov/vision/universe/roboticexplorers/black_holes_ripple.html

Myth or Reality?Black holes are

giant, cosmic vacuum cleaners that swallow up everything around them.

http://amazing-space.stsci.edu/resources/myths/black_holes.php.p=Teaching+tools

MythReality: Black holes do not suck up nearby material. If the Sun were

magically converted into a black hole, Earth's orbit would not change. Material generally falls into a black hole when it collides with other material orbiting the

black hole. The collision alters the material's orbit. Instead of orbiting a

comfortable distance from the black hole, the material is now orbiting too close to

the black hole. Then the black hole's enormous gravity traps the material in a

one-way spiral to oblivion.


Myth or Reality?You can see a black hole.


MythThe light produced or reflected by objects makes them visible. Since no light can escape from a black hole, we can't see it.

Instead, we observe black holes indirectly by their effects on

material around them.


Myth or Reality?Black holes lead to other places.


MythIn science fiction shows, people sometimes travel

through wormholes. Many students think black holes

are wormholes and therefore lead to other places.

Wormholes don't exist; they are merely a hypothesis.


Dark Matter About 90% of

galaxies consist of dark matter.

Black holes are a type of dark matter.

http://hubblesite.org/gallery/album/entire_collection/pr2007017a/

Micro Black Holes These black holes

are hypothetical. Their mass would

be less than a star.

The smallest possible black hole. http://www.spaceflavors.com/

Stellar Mass Black Holes

These black holes are formed by the gravity from the death of a massive star.

The star has a supernova explosion when it dies and the corpse becomes a black hole.

http://www.teo.net/astronomy/stellar-mass-black-holes/

Intermediate Black Holes

These black holes have significantly larger mass than stellar mass black holes.

And are significantly smaller than supermassive black holes.

http://astro.ucla.edu/announcements/press.shtml

Supermassive Black Holes

These are the most massive black holes.

Scientist have evidence that there is a supermassive black hole in the center of each galaxy including the Milky Way.http://www.ociw.edu/news/midweightblackhole

How they are formed

When a giant star dies, all of its mass is squeezed in a single point.

Time and space stop

Mass has no volume and time does not pass

http://www.ifa.hawaii.edu/~barnes/ast110_06/bhaq.html

Parts of a black hole The center of a black

hole is called the singularity.

Within a certain distance from the black hole is the event horizon. This is where the gravitational force is so strong, anything that passes will be sucked in, including light.

http://www.eclipse.net/~cmmiller/BH/blkbh.html

Parts of a black hole continued...

The more massive the singularity, the larger the event horizon.

The event horizon is the point where nothing can go back.

Nothing gets sucked into the event horizon, it has to pass through it to become caught in it.

Gravitational Force Albert Einstein was

the first to discover gravity in 1916.

Gravitational waves are created when two big masses spin, collide or explode.

http://www.ifj.edu.pl/~stachnie/einsteine.html

Gravitational force of a black hole

The gravitational force of a black hole is the same as when it was a star.

Our sun is an average size star, if it were to die and become a black hole the Earth's orbit would not change because the gravitational force would not change. This is why objects such as planets are safe from black holes.

http://www.daviddarling.info/encyclopedia/S/supermassive_black_hole.html

Spaghettification in Black Holes

When the gravitational force is so strong it stretches objects into long, thin shapes like spaghetti.

No object can resist this strong gravitational force near black holes.

http://www.youtube.com/watch?v=1bz8nNZr2d4 http://www.dawn-alleria.com/viewtopic.php?id=432

Finding a black hole Although black

holes are black, when matter falls into them, it can heat up so much that it glows in x-rays.

http://imagine.gsfc.nasa.gov/docs/science/mysteries_l1/massive.html

In the Milky Way Galaxy

Scientist have evidence that they have found a black hole in the center of our galaxy.


In the Milky Way Galaxy

The evidence for this is a star near the center of our galaxy is spinning at speeds of up to 3000 miles per second. That is REALLY fast!

Only a black hole 3 million times the size of our sun could cause a star to move so fast


Questions about black holes

If you want to know more about black holes, ask your parents to look at these web sites

http://imagine.gsfc.nasa.gov/docs/ask_astro/black_holes.html

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Black Holes l