Geometry.Net - Basic_B: Black Holes

WELCOME TO EXIT MUNDI: A COLLECTION OF END-OF-WORLD SCENARIOS
A variety of apocalypses meteors, black holes, technological disasters, weird physical phenomena, religious writings, robots, and aliens.
http://www.xs4all.nl/~mke/exitmundi.htm
Geometry Around Black Holes. Kerr's Rotating Black Holes.
A brief mathematical description of this phenomenon and diagrams of the mathematical results.Category Science Physics Relativity black holesKerr's rotating black holes. Let's generalise some of the formulas used inthe static Schwarzschild case, to the case of rotating black holes.
http://www.astro.ku.dk/~cramer/RelViz/text/exhib4/exhib4.html

Extractions: Let's generalise some of the formulas used in the static Schwarzschild case, to the case of rotating Black Holes. The Kerr metric is written in Boyer-Lindquist coordinates: where the coordinate functions are given (with G=c=1): the specific angular momentum is: The physical value of J is for a star like the sun: corresponding to a M . If a =0 we have the Schwarzschild case for a nonrotating Black Hole (or star). We define FIDucial Observers (FIDOs) as little (experimental) physicists locatedat each point in spacetime measuring all possible physical quantities in their local proper units. They'll get a hard job in the Kerr geometry. To keep their job, they have to follow the geometry which actually rotates with increasing speed towards the center. How can this be? All physical objects are dragged into circular motion by the Black Hole's rotation. Our FIDOs (which are supposed to be at rest) will follow the (absolute) space around the rotating hole. The Boyer-Lindquist coordinates naturally includes this rotating coordinate system, so in the Kerr reference frame, the geometry actually swirls like the air in a tornado. The angular velocity of a FIDO as viewed from infinity is: This angular velocity depends on a and r. The larger a, the larger
Tyrell Corp. - Solar Storm Monitor
Space, Space Weather, Satellites, black holes, Neutron Stars, Near Earth Objects, Space Fungus, Computer Environmental Tester
http://www.angelfire.com/geek/solarstormmonitor
Spacelink - Black Holes
black holes are extremely compact space objects that were once massive starswhich collapsed inward due to the force of their own gravity. black holes.
http://spacelink.nasa.gov/Instructional.Materials/Curriculum.Support/Space.Scien

Extractions: Where am I? NASA Spacelink Home The Library Instructional Materials Curriculum Support ... Stars Galaxies and Amazing Phenomena Black Holes Black holes are extremely compact space objects that were once massive stars which collapsed inward due to the force of their own gravity. Take a journey into a black hole through a quick time movie or research Einstein's Theory of Relativity using this list of exciting resources. [Some of these links will take you out of NASA Spacelink. To return, use the Back button on your browser or bookmark this page for later reference.] Pictures of Black Holes - These are images taken by the Hubble Space Telescope. Game-Fall Into a Black Hole - NASA's Jet Propulsion Laboratory offers this board game from Space Place. Download and print out the gameboard and pieces and be the first to explore a black hole and live to tell about it! The Truth About Black Holes - The Space Telescope Science Institute (STSCI) introduces "The Truth About Black Holes" on its Amazing Space website. Venture into the world of black holes and discover amazing facts through animations, artists' images, vivid descriptions, and classroom tips for educators. Constellation-X Telescopes - This team of x-ray telescopes will orbit close to each other and work in unison to simultaneously observe the same distant objects. Excellent information about black holes, dark matter, x-ray jets, dead stars and exploding galaxies.
Slashdot: News For Nerds, Stuff That Matters
This site covers everything from 'Microsoft Privacy Policy' to 'How to Avoid black holes', taking in 'DoE computer simulations of secondary nuclear explosions'.
http://www.slashdot.org/

Extractions: Gentu writes "The main commercial company behind NetBSD is Wasabi Systems . The company has contributed advances and big chunks of code to the open source project, while they do offer a boxed release of NetBSD. However, their main business for the company is the embedded market and NetBSD is marketed as an embedded OS. OSNews talked to the Vice President of Wasabi Systems, Jay Michaelson. Linux in the embedded market is also discussed." Read More... of comments Ask Slashdot : Complex Language Support for PDA's? Posted by Cliff on Thursday April 03, @11:20PM
[gr-qc/9912119] The Thermodynamics Of Black Holes
This review includes discussion of classical black hole thermodynamics, Hawking radiation from Category Science Physics Relativity black holes Thermodynamics
http://xxx.lanl.gov/abs/gr-qc/9912119

Extractions: We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues. References and citations for this submission:
Zooming In On Black Holes
Astronomers are using radio signals and an orbiting telescope to view black holes in quasars billions of light years away. By Kristen Philipkoski. Wired News
http://www.wired.com/news/news/story/15140.html
Abholes
black holes, White Holes, Worm Holes. How can black holes ever capture anything since2body capture is dynamically forbidden? Do black holes have zero volume?
http://image.gsfc.nasa.gov/poetry/ask/abholes.html

Extractions: Black Holes, White Holes, Worm Holes How can black holes ever capture anything since 2-body capture is dynamically forbidden? Can nuclear fusion happen near a black hole? How do astronomers really prove that black holes exist when they are just theoretical ideas? Can a star clog a black hole that is swallowing it? ... How do we know that Einstein's equations actually work just inside a black hole's event horizon?
Black Holes Of A Different Color?
What color is a black hole? It's not a trick question. Astronomers claim they've found brightpink black holes in galaxies that are more than 1 billion light-years away. By Leander Kahney. Wired News
http://www.wired.com/news/news/story/19554.html
Black Holes - Science Background
No Escape The Truth About black holes. Teacher Page Science Background. Index Fordetails, consult any popular book on black holes. Back to Top .
http://amazing-space.stsci.edu/resources/explorations/blackholes/teacher/science

Extractions: Selected references Science background: The following information is provided to give the teacher some additional knowledge about the effect of gravity and black holes. This material can be used to inspire research topics for students or to encourage class discussion. Back to Top 1. What is a black hole? Back to Top 2. How is a black hole created? To create a massive core a progenitor (ancestral) star would need to be 10 - 20 times more massive than our Sun. If the core is very massive (approximately 2.5 times more massive than the Sun), no known repulsive force inside a star can push back hard enough to prevent gravity from completely collapsing the core into a black hole. Then the core compacts into a mathematical point with virtually zero volume, where it is said to have infinite density. This is referred to as a singularity. When this happens, escape would require a velocity greater than the speed of light. No object can reach the speed of light. The distance from the black hole at which the escape velocity is just equal to the speed of light is called the event horizon. Anything, including light, that passes across the event horizon toward the black hole is forever trapped.
Gravity Tutorial Contents Page
From a student at the Curtin University of Technology in Australia, a tutorial with three levels introductory, intermediate, and advanced. Includes the history of gravity, orbits, air resistance, laws, escape velocity, and black holes.
http://www.curtin.edu.au/curtin/dept/phys-sci/gravity/
GRAVITATIONAL / UNIVERSAL ENGINEERING
Scientific and mathematical modeling of physics including, gravity, space, antigravity, dark matter, solution to the n-body problem, expansion rate of the universe and black holes, which suggests the development of field propulsion for advanced space flight.
http://www.gravitational-engineering.com/

Extractions: GRAVITATIONAL / UNIVERSAL ENGINEERING Gravitational / Universal Engineering creates practical models which can be applied to solve real problems including: gravity, space flight by field propulsion, anti-gravity effects, dark matter, n-body problems, expansion of the Universe. A) QUANTITATIVE MODELING 1. Contraction of Space as the Mechanism for Universal Gravitation Pseudo Force of Gravity, Acceleration due to Gravity Redefined, Independent Derivation of Universal Gravitation, Revised Laws of Motion, Natural Dynamic of Space, Solution to N-body Problems, Dark Matter, Expansion vs. Contraction Rate of Universe, Graphical Models, Fate of the Universe 2. Gravity Modeled as Dynamic Geometry Eliminates Need for Dark Matter Redefining Space, Reduction of Space by Mass, Acceleration of a 1, 2 and 3 Body System, Illustrated Solutions to N-body Problems, Missing Mass of the Universe, Cumulative Effects of Gravity, Special Case of Linear 3-Body Problem, Dark Matter Non-Existent, Conclusion B) CONCEPTUAL AND SPECULATIVE THEORY 3. Concept of a Fundamental Element
HubbleSite - NewsCenter - 1997 - 01 - Massive Black Holes Dwell In Most Galaxies
News Media Resources. Massive black holes Dwellin Most Galaxies, According to Hubble Census
http://hubblesite.org/newscenter/archive/1997/01/

Extractions: View all images Announcing the discovery of three black holes in three normal galaxies, astronomers suggest that nearly all galaxies may harbor super-massive black holes that once powered quasars (extremely luminous objects in the centers of galaxies), but are now quiescent. This conclusion is based on a census of 27 nearby galaxies carried out by the Hubble telescope and ground-based observatories in Hawaii. The three galaxies in these images are believed to contain central, super-massive black holes. The galaxy NGC 4486B [lower left] shows a double nucleus [lower right]. The picture at lower right is a close-up of the central region of NGC 4486B. Read the full press release text Credit: Karl Gebhardt ( University of Michigan ), Tod Lauer ( NOAO ), and NASA
Radio Telescopes Astronomy's Next Big Wave
Astronomers in New Mexico are using radio telescopes to get images from black holes and quasars that optical telescopes aren't able to deliver. They did it by lofting an antenna into space. Wired News
http://www.wired.com/news/news/story/4928.html
BLACK HOLE LINKS
A set of links to numerous black holes resources on the Web. A great starting point to finding some Category Science Physics Relativity black holesblack holes. Part One ASTRONOMICAL black holes. OBSERVATIONS(?) OF black holes BlackHoles Within Galaxies Milky Way What is Sgr A*?, by Heino Falcke, 94/11.
http://web.mit.edu/afs/athena.mit.edu/user/r/e/redingtn/www/netadv/bh.html

Extractions: As Astronomical Objects or In Field Theory Part One: ASTRONOMICAL BLACK HOLES General Observations (?) of Black Holes Evaporation Thermodynamics ... BLACK HOLES IN FIELD THEORY GENERAL: Advanced: Event Horizons: /Interactions and Dynamics of Black Holes: Accretion Disks: Merger Rate Estimates: OBSERVATIONS(?) OF BLACK HOLES: Black Holes Within Galaxies: Milky Way: What is Sgr A*?, by Heino Falcke, 94/11
HubbleSite - NewsCenter - 2000 - 03 - Lone Black Holes Discovered Adrift In The
Lone black holes Discovered Adrift in the Galaxy All previously known stellar black holes have been found orbiting normal stars.
http://hubblesite.org/newscenter/archive/2000/03/
StarChild: Black Holes
What is a black hole and how do we know it exists?(for K4th graders)Category Kids and Teens School Time black holes black holes. Some scientists believe that there is a black hole in our very ownMilky Way. black holes were once massive stars that used up all their fuel.
http://starchild.gsfc.nasa.gov/docs/StarChild/universe_level1/black_holes.html

Extractions: Black Holes Some scientists believe that there is a black hole in our very own Milky Way. Black holes were once massive stars that used up all their fuel . As they died out, they collapsed inward due to the pull of their own gravity . The gravity of a black hole is so powerful that not even light can escape its pull! Once any matter falls into a black hole, it disappears from the visible Universe It is very hard to see a black hole. Any object that gets too close to a black hole will be pulled inside it. We only know they are there because of the effects they have on other objects that are near them. Any object, whether some dust, or a star, or anything, that gets too close to a black hole will be pulled inside it. As the objects fall toward the black hole, they heat up and get very hot. Scientists can use special instruments to detect the heat the objects give off. That is how we know the black hole must be there.
Black Holes
HOW DO WE SEE black holes ? John Blondin Theoretical AstrophysicsDepartment of Physics North Carolina State University.
http://wonka.physics.ncsu.edu/~blondin/Blackhole/title.html
Dark Stars, Black Holes, Bright Galaxies
One huge page packed with illustrations, diagrams and photographs portraying some interesting aspects of stars, black holes and galaxies.
http://www.vuw.ac.nz/~mackie/royal_society/alpha/alpha.html
Taking The Cosmic Shortcut - ABC Science Online
The future, Einstein's special theory of relativity, the past, theory of gravitation, black holes, wormholes, negative energy and links.
http://www.abc.net.au/science/slab/wormholes/default.htm

Extractions: This article originally appeared in the February 2002 edition of Helix Imagine seeing the dinosaurs first-hand, visiting your great, great, great grandchildren in the 22nd Century, or travelling to the other side of the Milky Way in an instant. Time travel and wormholes used to belong to the realm of make-believe. But, with a little inspiration from some creative writers and thinkers, Elizabeth Warnes says physicists have begun to show us that science fact can be just as strange as science fiction. Travelling into the future... Dr Charley Lineweaver, Professor Ray Norris, Dr Joss Hawthorne and Tamara Davis online to discuss the possibilities and paradoxes of time travel and wormholes You can read what they had to say here Einstein's special theory of relativity shows that time travel into the future is possible. The theory demonstrates that the way we perceive time is relative to our motion. Objects travelling at speeds close to the speed of light (about 300 000 kilometres per second) age more slowly than stationary objects. In 1975, Professor Carrol Alley tested Einstein's theory using two synchronised atomic clocks. Carol loaded one clock onto a plane, which was flown for several hours, while the other clock remained on the ground. At the end of its flight, the clock on the plane was slightly behind the one on the ground. Time had actually slowed down for the clock on the plane. It had travelled forward in time.

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