For many years time travel was the stuff of science fiction. This was all just part of the world's imagination until recently. Scientists now believe that the current laws of physics allow us to travel though time. They believe that we can now travel back to see our founding fathers sign the declaration of independence. We could travel to 2999 to witness the birth of the next new millennium. Such travel would require a machine capable of withstanding great pressures and incredible amounts of speed.
The act of actually traveling though time is for the most part, agreed upon, but the implications of such travel is not so decided upon. Many different theorists have different views of what could happen and some go, as far as to say that if we did travel to the past, we would end up in a different universe that is a replica of this one. One of the most basic concepts is that of Dilation, a stretching of something. Some scientists believe that the main gateway to the past or future is a wormhole. Einstein's general relativity theory explains about universal constants, this is important to understand the concepts of travel at light speed.
Traveling to the past could create problems if someone tried to change something. This is a paradox. A few of these paradoxes are explained through the use of quantum mechanics. Sailing though the cosmos at the speed of light with no time passing us by, moving throughout time to witness the ancient Egyptians create their masterpieces. This is an exciting concept that we could actually formulate and make happen.
Before the time of Einstein, Newton and other great investigators thought of space as an infinite expanse in which all things exist (Hewitt 213). We are in space and we live in it along with all of the planets and stars. It was never clear if the universe exists in space or space exists in the universe. Dose space exists outside the universe or only within the bounds of it. The similar question, does the universe exist only in time or does time only exist in the universe? Was there time before the universe, and will there be time after it ceases to exist? "Einstein's answer to this is that time and space only exist within the universe. There is no time or space 'outside.' (Hewitt 213) " Einstein said that space and time are two separate parts of a whole called space-time (Hewitt 213).
To understand this, consider our present knowledge. We move though time at the rate of 24 hours per day. This is only half the story though. To get the other half we have to convert our thinking from moving though time to moving though space-time (Hewitt 213). When we move, we not only move through space, we move though time. This is the idea of space-time.
If a person were to stand still, they would be moving only though time. If they moved a little bit, they would be moving though space a little bit, but still mostly though time. If one were to travel at the speed of light, what changes would they experience in time? The answer is simple; they would be traveling through space, with no travel though time (Hewitt 214). They would be as ageless as light, for light travels though space only (not time) and is timeless. > The frame of reference of a photon, a particle of light, a trip across the universe would take no time at all (Hewitt 214). To understand how traveling though time would work, we must first understand how time and space can be stretched.
Motion in space affects motion in time. Whenever we move through space, we to some degree alter our rate of motion in time. This is known as time dilation, a stretching of time that occurs ever so slightly for everyday speeds, but significantly for speeds approaching the speed of light. If we were to attempt to travel to the nearest star, Alpha Centauri, which is 4 light years away, even traveling at the speed of light would take 8 years round trip (Hewitt 228). The center of our galaxies is something like 30000 light years away and at the speed of light would take 30000 years to get there.
We could not possibly survive that long. These arguments fail to take in to account of time dilation though. Time for a stationary observer on earth and for an astronaut on a spaceship of high velocity is different. A person's heart beats to the rhythm of the realm it is in. One realm of time seems the same as any other to the person in the realms, but not to an observer outside that realm that can see the difference. As an example, astronauts traveling at 99% the speed of light could make a trip to the star Procyon that is 11.
4 light-years away in 23 earth years round trip (Hewitt 229). Because of time dilation, it would seem that only 3 years passed for the astronauts, there clocks would be 3 years older; they would be biologically only 3 years older (Hewitt 229). It would be the mission control people that would appear to be 23 years older. The question is why dose this happen. Let's say that we are in our hometown, looking at the grandfather clock that is in the center of town. The clock reads 12: 00 noon.
Light from the sun bounces off the face of the clock and hits our eyes. We then turn our head and the light misses us and travels off into space. In space, there is a space ship that is traveling at the speed of light. An astronaut looks out his passenger-side window and sees the reflection of the clock. It reads 12: 00 noon. As he continues to move at the speed of light, he keeps up with the reflected face of the clock.
In the space ship time would pass as normal, but time in the universe would have seemed to stop. This might sound like cosmic bologna but the idea has been proven. In 1975 Professor Carl Tillie of the University of Maryland tested this theory using two synchronized atomic clocks (Brian par 2). One clock was placed on a plain and flown for several hours while he other clock stayed on the ground. Upon landing, the clock on the plain was a little slower than the one on the ground. This was not due to experimental error, for the same test was done several times and each time yielded the same results.
Because of time dilation travel in to the distance future is a definite possibility. The only problem lies in propelling a craft to such speed at which light travels. Carl Sagan wrote a science fiction novel about a fictional device that allowed his character to travel great distances across the universe. "Those faster than light speeds are not achievable; he also knew there was a common convention in science fiction that would allow a gimmick of a shortcut through 'Hyper space' as a means around this problem (par 2)." Sagen turned to Kip Thorne for help for hyperspace connections through space-time (par 2). A black hole always has two "ends", a property ignored by everyone except a few mathematicians until the mid-1980 s. Thorne was sufficiently intrigued to set two of his Ph.
D. students, Michael Morris and Ulv i Yurts ever, the task of working out some of the details of the physical behavior of what the relativists know as " wormholes." By starting out from the mathematical end of the problem, they constructed a space-time geometry that matched Sagan requirement of a wormhole that could be physical traversed by human beings. Sagan was right; hyperspace connections do at least in theory provide a means to travel to far distant regions of the universe without spending thousands of years putting around in an ordinary spacecraft. Since the 30's scientists have speculated that wormholes exist. Einstein's theory combines 3 dimensional space with time to create a 4 dimensional space (Brian par 3). Wormholes are gateways between two different parts of the universe made by linking two....