In general relativity, a white hole is a hypothetical region of spacetime which cannot be entered from the outside, although matter and light can escape from it. In this sense, it is the reverse of a black hole, which can only be entered from the outside and from which matter and light cannot escape. White holes appear in the theory of eternal black holes. In addition to a black hole region in the future, such a solution of the Einstein field equations has a white hole region in its past. However, this region does not exist for black holes that have formed through gravitational collapse, nor are there any known physical processes through which a white hole could be formed. Although information and evidence regarding white holes remains inconclusive, the 2006 GRB 060614 has been proposed as the first documented occurrence of a white hole.
The Heavy Twelves – Psychotropic
Eprom – Raw Data
somejerk – Blaze It
Ivy Lab – Magikess
NPHONIX & Dope D.O.D. – Broken Leg Funk (Sideswipe Remix)
Interstellar travel is the term used for hypothetical manned or unmanned travel between stars. Interstellar travel will be much more difficult than interplanetary spaceflight; the distances between the planets in the Solar System are less than 30 astronomical units (AU)—whereas the distances between stars are typically hundreds of thousands of AU, and usually expressed in light-years. Because of the vastness of those distances, interstellar travel would require either great speed, a high percentage of the speed of light, or huge travel time, lasting from decades to millennia or longer.
The speeds required for interstellar travel in a human lifetime far exceed what current methods of spacecraft propulsion can provide. Even with a hypothetically perfectly efficient propulsion system, the kinetic energy corresponding to those speeds is enormous by today’s standards of energy production. Moreover, collisions by the spacecraft with cosmic dust and gas can produce very dangerous effects both to passengers and the spacecraft itself.
A number of strategies have been proposed to deal with these problems, ranging from giant arks that would carry entire societies and ecosystems, to microscopic space probes. Many different spacecraft propulsion systems have been proposed to give spacecraft the required speeds, including nuclear propulsion, beam-powered propulsion, and methods based on speculative physics.
For both manned and unmanned interstellar travel, considerable technological and economic challenges need to be met. Even the most optimistic views about interstellar travel see it as only being feasible decades from now—the more common view is that it is a century or more away. However, in spite of the challenges, if interstellar travel should ever be realized, then a wide range of scientific benefits can be expected.