Black+Holes+-+DS

Getting Started
 * **Click on the edit button above to put your own content on this page.**

Rubric: [[file:Space Exploration Adventure Rubric.doc]], [[file:Space Exploration Adventure Rubric.pdf]]

 * Written Information **: //As you enter text, the area will expand. Make sure to check the required details of the assignment and review the rubric (see document links) to self-assess your work. Your paragraphs will be in block format, enter one return between paragraphs. The tab key, indent feature will not appear when typing directly into the wiki page.//

Visuals

//Make sure to include the location of your images; add a caption with this information//

 * ===[[image:http://www.nasa.gov/images/content/279256main_BlackHole_1-xltn.jpg width="337" height="287" caption="Gases being sucked into a black hole http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.html"]]=== ||  || [[image:http://upload.wikimedia.org/wikipedia/commons/0/03/Black_hole_lensing_web.gif width="447" height="401" caption="Simulation of gravitational lensing by a black hole, which distorts the image of a galaxy in the background http://en.wikipedia.org/wiki/Black_hole"]]

||
 * [[image:http://hubblesite.org/explore_astronomy/black_holes/graphics/encyc_physics.jpg width="428" height="308" caption="The Nature of Black Holes http://hubblesite.org/explore_astronomy/black_holes/encyclopedia.html"]] ||  || [[image:http://callisto.ggsrv.com/imgsrv/FastFetch/UBER1/00183123-T3 width="359" height="279" caption="This picture shows space debris being sucked into the strong gravitational pull of a black hole http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.html"]]

||
 * [[image:http://perpendicularity.org/blog/wp-content/uploads/2012/01/spiral_galaxy_1.jpg width="453" height="408" caption=" http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-a-black-hole-k4.html"]] ||  ||   ||

**Works Cited** // **Sources** : Include the source information for all of the magazine articles, reference sources (encyclopedias) and web site pages that were used to complete your project. The source information for encyclopedias may be found at the end or beginning of each entry in iCONN. When using periodicals, the publication information will be at the beginning or end of the article. This needs to be formatted for MLA standards. If it is not labeled 'Source Citation' it can be formatted appropriately by using EasyBib.com. You should use EasyBib for the web sites. The final Works Cited should be listed in alphabetical order by the first word of the source citation.//

//** Sample :**//

//"Milky Way." Kids InfoBits Presents: Astronomy. Gale, 2008. Reproduced in Kids InfoBits. Detroit: Gale, 2012.// //"The Milky Way." WMAP's Universe. NASA, 28 June 2010. Web. 06 Mar. 2012. .// //Vergano, Dan. "Galaxy Bracketed by Big Bubbles." USA Today 10 Nov. 2010: 05A. Web. 6 Mar. 2012.//


 * Your Source List:**
 * 1) "Black hole." //U*X*L Encyclopedia of Science//. U*X*L, 2009.//Gale Science In Context//. Web. 9 Mar. 2012.
 * 2) "Black Holes." //Kids InfoBits Presents: Astronomy//. Gale, 2008. Reproduced in Kids InfoBits. Detroit: Gale, 2012
 * 3) []
 * 4) []
 * 5) []

**Topic: Research Focus**

//What is your topic?// **BLACK HOLES **
//State the focus of your research:// Gravitational pull and what forms them.

**Notes** ==== // Include notes, statistics and facts that you will use to write your final paper. You may want to label sections of your notes to help you be more organized as you write. As you take notes from a source, you should list the source citation in the Works Cited section above. // ====
 * **Black holes are pockets of space with a gravitational pull so strong that nothing can escape. **
 * **A black hole is one of the strangest objects in space. It is invisible. Anything that gets pulled into a black hole is never seen again. **
 * ** Scientists think black holes are created by supernovas. When giant stars die they explode. The explosion of a star is called a supernova. It, the star, is big enough, a black hole is created after the supernova. **
 * ** After the supernova, the star shrinks. The left over matter becomes very dense. The black hole's gravity is so powerful that nothing can escape it, not even light. **
 * ** Black holes are invisible, but scientists know they exist. Because a black hole has such strong gravity, it pulls materials like dust, stars, and gas toward it. A black hole is like a powerful vacuum cleaner sucking up all the space debris. **
 * ** Using powerful telescopes, scientists can study the effects the black hole has on the area of space around it. They can see gases spiraling into the black holes. **
 * ** Scientists have found evidence of black holes in the center of several galaxies. They have even found a black hole in our own galaxy. It is the size of three million suns. It is 24,000 light years from Earth. It is too far way to be dangerous. **


 * **Black holes obey all laws of physics, including the laws of gravity.**
 * **In 1687, Isaac Newton showed that all objects in the Universe attract each other through gravity. Gravity is actually one of the weakest forces known to physics. In our daily life, other forces from electricity, magnetism, or pressure often exert a stronger influence. However, gravity shapes our Universe because it makes itself felt over large distances. For example, Newton showed that his laws of gravity can explain the observed motions of the moons and planets in the Solar System.**
 * **Albert Einstein refined our knowledge of gravity through his theory of general relativity. He first showed, based on the fact that light moves at a fixed speed (671 million miles per hour), that space and time must be connected. Then in 1915, he showed that massive objects distort the four-dimensional space-time continuum, and that it is this distortion that we perceive as gravity. Einstein's predictions have now been tested and verified through many different experiments. For relatively weak gravitational fields, such as those here on Earth, the predictions of Einstein's and Newton's theories are nearly identical. But for very strong gravitational fields, such as those encountered near black holes, Einstein's theory predicts many fascinating new phenomena.**


 * ===**Black holes cannot be seen because matter, light, and other forms of energy do not escape from them. They can possibly be detected, however, by their effect on visible objects around them. Scientists argue that as gaseous matter swirls in a whirlpool before plunging into a black hole, that heated matter emits fluctuating x rays. Discovery of such a condition in space, therefore, may indicate the existence of a black hole near the source of those x rays.**===
 * ===Suppose that you are standing on the surface of a planet. You throw a rock straight up into the air. Assuming you don't throw it too hard, it will rise for a while, but eventually the acceleration due to the planet's gravity will make it start to fall down again. If you threw the rock hard enough, though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity. The Earth's escape velocity is 11.2 kilometers per second (about 25,000 m.p.h.), while the Moon's is only 2.4 kilometers per second (about 5300 m.p.h.).===
 * ===Now imagine an object with such an enormous concentration of mass in such a small radius that its escape velocity was greater than the velocity of light. Then, since nothing can go faster than light, nothing can escape the object's gravitational field. Even a beam of light would be pulled back by gravity and would be unable to escape.===
 * ===The idea of a mass concentration so dense that even light would be trapped goes all the way back to Laplace in the 18th century. Almost immediately after Einstein developed general relativity, Karl Schwarzschild discovered a mathematical solution to the equations of the theory that described such an object. It was only much later, with the work of such people as Oppenheimer, Volkoff, and Snyder in the 1930's, that people thought seriously about the possibility that such objects might actually exist in the Universe. (Yes, this is the same Oppenheimer who ran the Manhattan Project.) These researchers showed that when a sufficiently massive star runs out of fuel, it is unable to support itself against its own gravitational pull, and it should collapse into a black hole.===
 * ===You can't see a black hole directly, of course, since light can't get past the horizon. That means that we have to rely on indirect evidence that black holes exist.===
 * ===Black holes almost certainly exist, and one of their basic properties is that they trap light. However, it is also true that nothing exceeds the speed of light. In fact, the theoretical prediction of black holes is due to the General Theory of Relativity, which is built on the principle that the speed of light in a vacuum is constant. The analogy of a cannonball falling back to Earth with the trapping of light in a black hole is only a crude and suggestive one that is not correct at a fundamental level (for one thing, the cannonball has mass, but light does not; it turns out that this difference is critical, because massless particles MUST travel at light velocity, but massive particles CANNOT travel at light velocity)===