Essay On Time Travel To The Past
Essay on Time Travel
666 Words3 Pages
First of all, to give you a better concept of time I will use a personal theory of mine. When you look up at the sky at night, at the stars, what are you seeing? Do you think that collage of stars actually exists? Most of them do not. When you look at the sky at night you are seeing the past because it takes an obscene amount of time for the light from those stars to reach earth, and in that time those stars may have disappeared.
It works both ways. When an inhabitant, if there is one, on a planet around the star that you are looking at looks at our sun he is also seeing the past. So here we are, at the main idea of my speech - the possibility of different times and time travel.
The main question here is: How do…show more content…
This has been misinterpreted many times. Einstein said that no solid object can accelerate to the speed of light. He did not state that you could not harness the power of an object or energy already going the speed of light, or faster. Another restriction is that the faster you accelerate, your mass increases and therefore to meet the speed of light you would need an infinite amount of energy because your mass would be infinite. We'll ignore that for now.
. Dr. Steven Preston of London says that assuming we can propel to the speed of light, we would have to do it at a rate that the human body can withstand. We will use 1g, that being 1 gravitational force, or the same as you simply standing on the ground. If we use Einstein's theory then we could accelerate to 1g in 354 days and just short of the speed of light. Using the star Andromeda as an example, which is 2.2 million light years away (a light year being the distance light travels in a year), at that 354th day we would reverse engines and slow down to halt at Andromeda. The entire trip would take less than 2 years, but unfortunately earth would have aged 2.2 million years. This is because, as I stated before, the faster you go time slows down. We have now established how to travel into the future
So how would you get back to your own time? Or how would you travel into the past? Dr. Preston says consider the speed of light a barrier, or essentially the present - that which cannot interact with the
Time travel is too dangerous for us to use. To prove this one must first understand time and whether time travel is possible. One must also look at the possible outcomes of traveling in time and take a look and space-time.
Time is relative; a day is a day because that is how long it takes earth to rotate on its axis. If we were to go another planet a day would be different, it could be longer or shorter. Also bodies moving at high velocities experience a time that ticks slower than the time measured at zero velocity. For example if someone were to take off from earth in a spaceship and travel at high speeds and then come back much more time would have passed on earth. On earth many years could have past while only a couple years passed for the traveler. This is called time dilation. Einstein's general and special theories of relativity allow for time travel into the future and past.
The future is defined by all events leading up to it. If a person travels to the future, meets his older self, and then commits suicide on the spot the existence of the older self is a paradox. He cannot exist if he committed suicide.
Time travel into the past is much more difficult. It would probably require speeds close to the speed of light and a source of energy as powerful as an exploding star. Wormholes and closed time like curves (CTC) can also be used for traveling into the past and future.
One other thing we have to look at before traveling in time is the Bucket Factor. In the Bucket Factor the universe can only hold so much matter. If someone were to go back into the past the past universe would have to much matter in it and so it would explode while the universe the time traveler came from would not have enough matter and would become a black hole. I like to call this making the universe suck and blow.
Space-time is four-dimensional. In space-time your life forms a four-dimensional "worm" with the head representation your birth and the tail end representing your death. An object is a three-dimensional cross section of this worm. The line upon which the object lies is its world line and relativity requires that this world line to be time like. Now the angle that someone's or something's world line makes with the time axis is a measure of that thing's speed. If massive objects were to distort space-time enough some worldliness would bend until they connected into closed loops. This world line would be time-like all around.
A world line that is time-like all around would have all the properties of time and space but would be a corridor to the past or a closed time-like curve (CTC). If we were to follow the CTC we could meet our past selves or if the loop was large enough visit our ancestors. Along the CTC you would come across everybody who has or will travel that CTC. But there are limits to a CTC. CTC's only reach back as far as they ere created you would only be able to back so far. Another thing is that CTC's can only hold a finite number of worldliness. It would get used up if traveled too much.
Wormholes are another way of traveling through time. Wormholes are holes on four-dimensional space-time; they are connected, and originate at different points in space and time. Wormholes provide a quick path between two points in space and time. A simple step into a wormhole and you would be transported to a different place and time. Wormholes would be the four dimensional equivalent of pinching two pieces of a folded sheet of paper together o make contact across the gap. Distortions in space cause the points separated be the gap to bulge out and connect. A machine could be made to create a wormhole but you'd only be able to go back as far as the machine was created.
There are many different theories as to the possible outcomes of time travel. The following are the most common theories.
Alternate universe- you travel back in time to save a person's life, return to your own time to discover you've only change an alternate reality.
Fate- you travel back in time to save a life only to find out it can't be avoided, or worse, you were the cause of their death.
Success- travel back in time and kill your great-grandfather, then you would never have been born so you couldn't have hone back to kill your great-grandfather.
Observer effect-you travel back and succeed in altering history, you would be the only person who would be capable of differentiating between the old reality and the new reality. With you existing out of time you may not be affected by the changes you inflicted on the timeline thus you become a stranger in the new present.
The blocked universe theory states that there is one timeline and travelers going into the past fulfill their destined roles. One flaw to this theory is that it assumes that the traveler is ignorant of the past and just stumble into it. But if the time traveler knows about the past there would have to be some kind of an anti-paradox force of nature to stop the tampering of history. Also if you could travel into your past to a place and time where there were no time travelers your mere arrival would be a paradox in a single timeline.
One main paradox is the grandfather paradox also known as the autonomy principle10. This paradox is created when a time traveler goes back in time to meet his grandfather. Upon their introduction the time traveler could change the course of events leading to your grandfather and grandmother being wed. The traveler could tell his grandfather a family secret to convince that he is who he says he is and his grandfather in turn tell his soon to be wife. His soon to be wife doubts the sanity of the traveler's grandfather and commits him. The time traveler's grandparents would have never gotten married so his mother wasn't born and the time traveler was created through autonomy. This paradox would rule out time travel, yet the laws of physics do not forbid it.
A way to solve a paradox is the multiple universes concept. Hugh Everett III proposed the multiple universe theory in 1957. Everett said, "that our reality is only one of many equally valid universes." Within every multiverse there are copies of every person, structure, and atom. Every possible event and outcome are said to be played out on a different universe. Some scientists think that these universes could be linked through time travel.
In conclusion time travel is possible but things like the bucket factor and the different outcomes can make time travel very dangerous. Someone could easily destroy the universe or change the time line and create a paradox. So in the end time travel is best left undiscovered. We just shouldn't be messing around with time.