Black Holes – Bending Time and Space

Authors Note
Explaining this phenomenon would literally take hundreds of pages, so I will try to be brief but yet provide meaningful explanations. It must be noted that some details must be dealt with in an abstract manner to avoid intricate mathematical explanations.

Theory Definition
Black holes are considered by many to be the most bizarre objects to ever exist in this universe. It is a theorized phenomenon in which an object or a region of space possesses an overwhelmingly large gravitational force to the point where even light gets pulled inside the hole. Generally speaking, for a region of space to possess a large gravitational field, it must be very dense in terms of mass concentration. Just like the name suggests, a black hole, in reality, is indeed black colored. This is due to the fact that neither matter nor light can escape from it, rendering the surface area of the hole being black. Black holes generally form when massive stars collapse at the end of their life time.

History Background
19th century: English geologist John Mitchell suggested it would be possible that a gravitational force, extraordinarily large, could in fact bend and pull light. This judgment led other scientists later to relate the Newtonian gravity as they knew it, with time, light, and massive objects.
20th century: It wasn’t until the genius of Albert Einstein came around with his general and special relativity theories that we have had a proper understanding of gravity. Einstein theorized radical justifications on how gravity can bend time, light, mass and space in what is now called the space-time context. This new concept describes gravity as a curvature of the space-time invariable which is caused by the presence of matter. Within this new and radical explanation, black holes could be addressed.
21st century: Micro black hole simulations were carried in high-tech laboratories in Ulf Leonhardt at the University of St Andrews, UK. By subjecting special type particles through massive part accelerators, some black hole parameters such as the event horizon (the area surrounding the black hole) were clearly noticed.

Bending Time
Since its discovery, there was something that was decidedly odd about the speed of light. It has been proven that the speed of light is the maximum speed any object, or a deviation there of, can acquire. Assume that the speed of light is denoted by [c], now if you travel at any speed, say three quarters the speed of light, and see a beam of light passing right by your medium, you will still measure the speed of light to be [c]. This stark discovery is very contrary to common sense and the classical physics which suggests that since you are in the same inertial frame with respect to the light, you should measure light to be travelling in what amounts to the difference in the two respective velocities lying at the same inertial frame (in this case one quarter of [c]).
How could this be? Einstein gave careful consideration to the observation. If light is always measured to be the same velocity, no matter how fast you are travelling, then there must be “something else” that is being compensated for to accommodate the speed of light. Einstein termed that this “something else” as “space-time”. In order for light to remain constant, space and time, hence space-time, have to vary and so they must be inextricably linked. Quite simply, as you approach light speed, time runs slower and space shortens.
The essence of Einstein’s theory is that mass tells space how to bend and space tells matter how to move. The mass of the Sun, a planet or indeed any mass in the Universe can bend the fabric of space. In other words: the greater the mass, the greater the distortion of space. This is important for time travel – because space and time are related, if you change one, you change the other. So if you bend space then you will bend time!

Example to Understand Time Bending:
Imagine two twins on Earth. One takes a trip into space at a speed very close to the speed of light. The other one remains on Earth. For the space-travelling twin, time starts to slow as he reaches a speed very close to that of light. However, for the twin on Earth, time passes normally. Finally, when the space-travelling twin returns home years later, a strange thing has happened; his Earth bound twin has gone grey. He has aged normally since his time was not slowed.
Unfortunately, it isn't quite that easy. Einstein predicted with special relativity that nothing could travel faster than the speed of light. Why? It's to do with mass. As you approach the speed of light, your mass increases. This is because space is shortening – it's squeezing up, so to speak, and so any matter is also squeezed. Quite simply, the faster you go the more squeezing takes place and the heavier you become. And the heavier you become the more force you need to move; or to put it another way, the harder you have to push to go faster. At the speed of light your mass becomes infinite, and so does the energy required to push you. Sadly then, you'll never travel at or faster than the speed of light.

OK, Enough! How does time travel relate to black holes?
According to general relativity, gravitation severely modifies space and time near a black hole. Now, we do know that black holes exert humungous gravitational field in their vicinity. Thus, as the horizon of a black hole is approached, time slows down relative to that of distant observers, stopping completely on the horizon. Once a body has contracted within the black hole’s radius, the body would, theoretically speaking, collapse to a dimensionless object of infinite density.

Links to Resources, Pictures, and Movies that illustrate the phenomena:
Resources:
http://en.wikipedia.org/wiki/Black_hole http://www.indiadaily.com/editorial/2583.asp http://cosmology.berkeley.edu/Education/BHfaq.html http://www.newscientist.com/channel/fundamentals/quantum-world/mg19726434.800-black-hole-event-horizon-created-in-the-lab.html http://archive.ncsa.uiuc.edu/Cyberia/NumRel/BlackHoles.html http://archive.ncsa.uiuc.edu/Cyberia/NumRel/RelUniverse1.html Pictures: http://www.tutorgig.com/ed/Image:Black_Hole_Milkyway.jpg http://www.damtp.cam.ac.uk/user/gr/public/bh_obsv.html http://space.newscientist.com/data/images/ns/cms/dn12089/dn12089-1_600.jpg http://www.spacetelescope.org/images/screen/heic0409a.jpg http://www.astro.umd.edu/~miller/bh.gif http://www.daviddarling.info/images/black_hole.jpg
Movies:
Simulation of Black Hole Collision (Recently done by NASA through a 10240 processors supercomputer!!!!): http://www.nasa.gov/centers/goddard/mpg/146898main_viz_shiftingall_21.320x240.mpg http://www.youtube.com/watch?v=l8yN77SpreQ
http://www.youtube.com/watch?v=hoLvOvGW3Tk