Monday, July 16, 2012

Finally, a machine that will propel on dark energy, faster than light i.e in FUTURE.

The discovery in 1998 that the Universe is actually speeding up its expansion was a total shock to astronomers. It just seems so counter-intuitive, so against common sense. But the evidence has become convincing.The evidence came from studying distant Type Ia supernovae. This type of supernova results from having a white dwarf star in a binary system. Matter transfers from the normal star to the white dwarf until the white dwarf attains a critical mass (the Chandrasekhar limit) and undergoes a thermonuclear explosion. Because all white dwarfs achieve the same mass before exploding, they all achieve the same luminosity and can be used by astronomers as "standard candles." Thus by observing their apparent brightness, astronomers can determine their distance using the 1/r2 law.Astronomers know dark matter is there by its gravitational effect on the matter that we see, and there are ideas about the kinds of particles it must be made of. By contrast, dark energy remains a complete mystery. The name "dark energy" refers to the fact that some kind of "stuff" must fill the vast reaches of mostly empty space in the Universe in order to be able to make space accelerate in its expansion. In this sense, it is a "field" just like an electric field or a magnetic field, both of which are produced by electromagnetic energy. But this analogy can only be taken so far, because we can readily observe electromagnetic energy via the particle that carries it, the photon.

Some astronomers identify dark energy with Einstein's Cosmological Constant. Einstein introduced this constant into his general relativity when he saw that his theory was predicting an expanding universe, which was contrary to the evidence for a static universe that he and other physicists had in the early 20th century. This constant balanced the expansion and made the Universe static. With Edwin Hubble's discovery of the expansion of the Universe, Einstein dismissed his constant. It later became identified with what quantum theory calls the energy of the vacuum.

A futuristic engine that uses dark energy to propel a spaceship faster than light is theoretically possible, and could revolutionise space travel, U.S. scientists say.The idea, backed up by calculations made by physicist Gerald Cleaver and graduate student Richard Orbousy, both of Baylor University in Waco, Texas, was published online on the physics website.

Not as unlikely as it seems, Like something from the world of Star Trek, their theory says that a spacecraft could travel at 'warp speed' in a bubble of space-time by manipulating dark energy, the mysterious invisible force accelerating the expansion of the universe (see, More evidence for dark energy's repulsive power, Cosmos Online).The spacecraft would essentially remain in the same place, they said, while space-time ahead of the spaceship shrank, and expanded again behind it.The warp engine is based on the 'Alcubierre warp drive', a mathematical model of a method of stretching space in a wave that was first proposed by Mexican physicist Miguel Alcubierre in 1994.

"Think of it like a surfer riding a wave," said Cleaver. "The ship would be pushed by the spatial bubble and the bubble would be travelling faster than the speed of light."The concept is based on new predictions emerging from string theory (a branch of theoretical physics which states that reality is based on one-dimensional objects called strings). String theorists believe space has not three or four but 10 dimensions: height, width, length, time and others that are unknown (see, A way to 'see' extra dimensions, Cosmos Online).


M-theory, which is as yet untested, unifies the various string theories by adding a further, 11th, dimension. Manipulating this 11th dimension exploits a loophole in Einstein's theory of relativity that says that travelling at faster-than-light speeds would take an infinite amount of energy."String theory suggests that dimensions are globally held compact by strings wrapping around them," the researchers write in their paper. "If this is the case, it may be possible to locally increase or decrease the string tension," they theorise, changing the size of the extra dimensions.Theoretical astrophysicists think that at the beginning of time, dark energy may have driven the universe to grow at faster than light speed for a short time.

And. as you all know, faster than light straight into the future.