Saturday, September 1, 2012

Time Dilation and Time Travel For the Average Reader

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First I'll start with Time Dilation in a step-by-step example that you most likely will not understand, and then explain it, followed by some famous ideas on time traveling:
In the middle of outer space, two people are flying...
One person is at low speed, let's say Charles Bronson is going 1,000 mph,
and Clint Eastwood is orbiting Charles at 99% light speed (cuz he's the freakin' man).
<1,000 mph       
664,000,000 mph>
According to Einstein (and proven experiments), Time Dilation will occur between them due to their large differences in speed. It is because Clint Eastwood is going very fast while Charles Bronson is going so slow that a large time differential between them will occur.
  • From Charles Bronson's perspective, Clint Eastwood is practically unmoving due to his high speed (slo-mo). (This effect would diminish if Charles were to increase his speed).
  • Inversely and simultaneously from Clint Eastwood's perspective, Charles is moving so fast that he can watch Charles live his entire life in a mere fraction of the time (fast-mo). From this perspective, for every full day that goes by for Clint Eastwood, Clint actually sees Charles Bronson experience a little over 7 days! (7.09 to be more exact).
NOTE: The inverse is true from Charles Bronson's perspective, so in 7 of *his* days, Clint Eastwood will only look like he experienced 1 actual day, hence, from this point of view Clint doesn't look like he's moving much at all (assuming that such a slow rate of movement can even be seen with the naked eye).
 So here's the thing to remember: Whoever is going fast sees slower objects moving fast even though they aren't, and whoever is going slow sees faster objects moving slow, even though they aren't either.
 The Confusing Part About Time Dilation: Both perspectives are seeing things correctly, relatively ... explanation below. (Einstein's Relativity simply means *from another person's perspective*)
(this might be a little complicated)
Time is not a constant in the universe. Speed can affect the rate of time for the moving object. Every single object in the entire universe that is not being affected by gravitational forces is experiencing its own rate of time down to the attosecond. The reason why you and I experience time at the same rate is because we don't move fast and because of the earth's gravity (try not to think to hard on this, unless you want to look at the formulae, you might not ever understand most of what makes time tick har har). In essence, it's better to say that the people on the earth are experiencing the earth's rate of time. This is because speed and gravity affect the flow of time and the curvature of space. Even light bends, and it is thought that time moves at the speed of light, and time can even be slowed or sped up by massive gravitational forces.
This is my face to the partial
Time Dilation formula below
A brief example: Humans experience a rate of time according to how the earth is experiencing time as it zips through space at tens of thousands of miles per hour. The earth is large enough (mass and gravity) that it bends space a little, causing it to curve some. In essence, we experience days and hours and minutes according to the earth. This does not mean that if a minute on earth passes that several minutes or a fraction of a minute might be experienced elsewhere in the universe. Time always travels at the speed of light (of time), however our **experience** and **perception** of it can speed up and slow down. 1 minute is always 1 minute, yet when Clint Eastwood looks at the slow moving Charles Bronson, 1 minute might be hours of movement for Charles from Clint's eyes, and vice versa.
So, what is time then? For a supreme lack of words to describe time, I'll simply say that time is a (semi)physical non-tangible entity in the universe that travels at the speed of light. We have the power to measure it, since it is a measurement of duration and length of time for crossing distances. From what we understand, time is actually real, to a certain degree. It is not merely an invention used to know where the Sun and Moon are, nor is it merely a tool we use to understand distances, rate, and duration. Time is sort of like an invisible current of water moving across every inch of the universe that travels at the speed of light that acts upon all objects within the universe. This means it **exhibits** tangible properties but it's not something you're gonna catch in a butterfly net anytime soon.
Re-emphasizing the examples: When an object (Clint Eastwood) travels almost at the speed of light, it takes time *longer* to catch up to Clint. Think of time as moving 100 mph and Clint is in a car going 99 mph...naturally it'd take longer to catch up to him than if he were going 3 mph. This delay in catching up to Clint is one way of visualizing how time is struggling to "affect" him or act upon him. And this delay is seen by us as slow-motion (our limited perspective). This means that **from Charles Bronson's slower perspective** he sees Clint going extremely slow (virtually standing still) since the time differential (the lag or time delay) is so large between them, and this is aptly called Time Dilation. The word dilation simply means to expand or enlarge, sort of like your eyes do after an eye exam, and for Clint, time is stretched so thin that it is barely even able to affect him. This raises two questions in your head, no doubt:
  1. Why does time need/seem to affect us like this? (Or to reword it, Does this "affection" indicate that this is the nature of time?)
  2. Does this mean that if we went exactly the speed of light, would time stop? (i.e.- time could not catch Clint)
The answers (or theories) are:
  1. We don't know why time acts on us like this. Oddly enough, humans seem to have an innate desire to keep track of time via memories of the past and a desire to control/plan for the future. To say that time is just a measurement completely denies how all animals on earth seem to have a brain capable of keeping track of the past, which seems to make time much more than what it seems. To say that the human brain tends to organize thoughts and memories in a hierarchy of "time" (past to present to possible future) would be a gross understatement. However, it seems that all we can really do to understand time is to study its physical aspects when they become apparent to us. When we see an object moving fast, we can measure the time differential between it, us and other objects. The problem is, time seems to be sorta physical and sorta not. We can physically observe it when it manifests itself (time dilation), but other than that we can't observe it. Since science is currently limited to studying the physical world, this means that time can only be studied when it acts on us physically (time dilation), and is invisible to us otherwise. This makes it virtually impossible to understand time, although there are plenty of theories that always seem lack evidence, even if they are very interesting.
  2. According to Einstein, going the speed of light is impossible for anything with even 1 mass, since at 1c//light speed (670,616,629.3843951 mph), even that tiny bit of mass gets multiplied infinitely. So that 1 becomes, which becomes 4, 8, 16, 32, 64, 128, and so on until the drag and fuel/energy drain on a ship or an object becomes so great it reaches its own maximum speed relative to its mass. In essence, light can go light speed because it has (essentially) no mass. What this boils down to is that Einstein said going light speed is impossible, however he did mention that somehow if you did, you would travel forward in time. Remember Clint and his "time delay" because of his speed? If he went light speed that means time would NOT be able to catch up to him, and essentially he'd live forever. experiencing 7.1 days for every 1 earth day until the end of the universe if he felt like it. But because time cannot catch him, he cannot age and cannot die. In essence, he'd still live 80 or 90 years, however, only when he slowed down. This means if he traveled at light speed for 100 of "his" years, then 259,327.5 earth years would pass by for his 100 years. While it might not be the most awesome way to time travel, you have to admit that for nearly 260,000 years to go by in 100 years for him, he could see the end of the universe in no time flat.
Time Travel: A third theory arises for our friend Clint-- What if he went faster than the speed of light? According to Einstein (who barely even talked about such fantastic nonsense), Clint would travel backward in time if he managed to go faster than light speed. Few respectable astronomers speak on this, since as a race we can't even space travel much at all, something of this incredible complexity is rarely even entertained and is purely conjectural, as there is no evidence (how can anyone understand time travel when they can't even understand time?)

If only Ultimecia had used "time dilation" instead
of "time compression," then she could have moved
super fast relative to Squall and watched his entire
life dwindle away in seconds. Then destroy
the universe! Yippee skippee!
That last sentence implies that when both people move at the same speed you could crudely (and incorrectly) say that they enter the same time phase, or the same time continuum or something like that. This is entirely wrong, but when I say it like this some people can kind of see what is attempting to be explained. Because time acts on us and affects our perceptions, how can time affect us as it normally would if we are moving so fast that it can't really catch up? Obviously there would be a delay. Our GPS satellites in outer space that let you use interactive maps in your car in real time actually experience time dilation and have to predict the time differential. This is why it seems like no GPS is ever able to know how fast your car is traveling and can never quite get the exact location of your destination (I swear my TOM TOM is regularly off by 1/4 mile and always thinks I'm traveling 5 mph slower than what I really am).
If you want to know more about what time travel might be like according to current theories, read my other article Time Travel?...Yes, But Not Like in Science Fiction. That about wraps up time dilation. I hope this article helps you to understand this remarkably difficult concept.

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