The Pros and Cons of Time Travel

"Time dilation" was propsed by Albert Einstein in his special theory of relativity. This theory states that, relative to a stationary observer, time appears to pass more slowly for faster-moving bodies, or bodies that are within a deep gravity well. For example, a moving clock will appear to run slow; as a clock approaches the speed of light it will appear to slow to a stop. This has given rise to the popular twin paradox. General relativity states that a similar effect would occur if the clock were to be close to a black hole.¹

Time perception can be apparently sped up for living organisms through hibernation, where the body temperature and metabolic rate of the creature is reduced. A more extreme version of this is suspended animation, where the rates of chemical processes in the subject would be severely reduced.¹

Time dilation and suspended animation only allow "travel" to the future, never the past, so they do not violate causality, and arguably should not be considered time travel.¹

Today, the only way to "travel" to the future cannot be used to travel over long periods of time -- only less than a single second. It is so insignificant that it is usually not mentioned at all. And the only people that have used this method have been astronauts. Basically, the longer a person is in orbit around the Earth, the younger the astronaut will be in relation to observers on Earth.¹ This is because the farther out from the center or the Earth one travels, the greater his or her circumference will be because his or her radius will be greater. Because Earth's radius is smaller than that of the orbiting individual it will complete a whole revolution faster, therefore a day would pass on Earth for observers before a day would pass for the orbiting individual.

For anyone who has taken a Physics course, he or should would know that velocity is indirectly proportional to time as seen in the basic equation v=d/t. So, according to this equation, as velocity increase, time will decrease and as velocity decreases, time will increase. In other words, they faster one travels, the less time is required to get to the destination. This brings up my personal example of time travel:

Two cars leave point A at the same time. The first car is traveling 55 mph and the second  at 65 mph. The second car will reach point B before the first car. Less time in needed since the second car is moving faster. Since each driver's perception of time is relative to their speed, this can be considered time travel.