Black Holes

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

2. 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

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

4. You can see a black hole. http://amazing-space.stsci.edu/resources/myths/black_holes.php.p=Teaching+tools Myth or Reality?

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

6. Black holes lead to other places. http://amazing-space.stsci.edu/resources/myths/black_holes.php.p=Teaching+tools Myth or Reality?

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

8. 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/

9. 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/

10. 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/

11. 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

12. 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

13. 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

14. 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

15. 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.

16. 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

17. 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

18. 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

19. 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

20. In the Milky Way Galaxy • Scientist have evidence that they have found a black hole in the center of our galaxy. http://www.nasa.gov/vision/universe/roboticexplorers/black_holes_ripple.html

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

22. 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