Time Travel : The Mystery Of All times

 Many have dreamed of figuring out how to travel in time—and dismissed it as impossible. Now, researchers have proposed a mathematical model that makes time travel possible, using concepts of Einstein’s theory of general relativity coupled with the hypothesis that time is not a separate dimension.

We think of the universe as being made up of three spatial dimensions, and a fourth dimension representing time. But mathematician Ben Tippett at the University of British Columbia, Canada, says this is wrong. He believes time should not be separated from other three spatial dimensions—instead all four run together, simultaneously.

“It is because time and space are attached together that the time machine to behave in this way,”

EINSTEIN’S THEORY AND EQUATIONS:

 Einstein's theory of special relativity says that time slows down or speeds up depending on how fast you move relative to something else. Approaching the speed of light, a person inside a spaceship would age much slower than his twin at home. Also, under Einstein's theory of general relativity, gravity can bend time.

Through A Warmhole

General relativity also provides scenarios that could allow travelers to go back in time, according to NASA. The equations, however, might be difficult to physically achieve.

One possibility could be to go faster than light, which travels at 186,282 miles per second (299,792 kilometers per second) in a vacuum. Einstein's equations, though, show that an object at the speed of light would have both infinite mass and a length of 0. This appears to be physically impossible, although some scientists have extended his equations and said it might be done.

A linked possibility, NASA stated, would be to create "wormholes" between points in space-time.

ALTERNATE THEORIES:

Infinite cylinder

Astronomer Frank Tipler proposed a mechanism (sometimes known as a Tipler Cylinder) where one would take matter that is 10 times the sun's mass, then roll it into very long but very dense cylinder.

After spinning this up a few billion revolutions per minute, a spaceship nearby — following a very precise spiral around this cylinder — could get itself on a "closed, time-like curve", according to the Anderson Institute. There are limitations with this method, however, including the fact that the cylinder needs to be infinitely long for this to work.

Black holes 
Another possibility would be to move a ship rapidly around a black hole, or to artificially create that condition with a huge, rotating structure.

"Around and around they'd go, experiencing just half the time of everyone far away from the black hole. The ship and its crew would be traveling through time," 

"Imagine they circled the black hole for five of their years. Ten years would pass elsewhere. When they got home, everyone on Earth would have aged five years more than they had."

Cosmic strings

Another theory for potential time travelers involves something called cosmic strings — narrow tubes of energy stretched across the entire length of the ever-expanding universe. These thin regions, left over from the early cosmos, are predicted to contain huge amounts of mass and therefore could warp the space-time around them.

Cosmic strings are either infinite or they’re in loops, with no ends, scientists say. The approach of two such strings parallel to each other would bend space-time so vigorously and in such a particular configuration that might make time travel possible, in theory.

Time machines

It is generally understood that traveling forward or back in time would require a device — a time machine — to take you there. Time machine research often involves bending space-time so far that time lines turn back on themselves to form a loop, technically known as a "closed time-like curve."

However, time-travel research suggests time machines are possible without exotic matter. The work begins with a doughnut-shaped hole enveloped within a sphere of normal matter. Inside this doughnut-shaped vacuum, space-time could get bent upon itself using focused gravitational fields to form a closed time-like curve. To go back in time, a traveler would race around inside the doughnut, going further back into the past with each lap. This theory has a number of obstacles, however. The gravitational fields required to make such a closed time-like curve would have to be very strong, and manipulating them would have to be very precise.

 Towards the END ( Conclusion)

The question remains, can we really take it to that extreme? And is it possible to go backwards or forward through time, too?

Once again, we don't really know. Einstein's theories tend to rule out rewinding time, but they're still theories. It's possible some future discovery could prove them wrong. As for the wormhole approach, we won't really know exactly how that works until we try it, and at the moment, we don't really have a feasible method for building a wormhole in space.

If you're really curious about time travel though, go see Interstellar. The science behind it is sound—if sometimes a bit fantastic—but the movie itself is very fantastic.[3]

By:AKB

REFERENCE:--

[1] http://www.newsweek.com/time-travel-physics-einstein-spacetime-tardis-592908

[2]https://www.space.com/21675-time-travel.html

[3]http://gizmodo.com/yes-time-travel-is-possible-heres-how-1654958816

4) credits for images:--google images.