Explore Einstein's Theory of Relativity & Time Travel

[Newtonians]

I am by no means an educated scholar in the field of Einstein's theory of relativity, so introducing myself into this topic is rather green. After watching a couple videos on time travel, I noticed something that came to me as contradictory:


In this video, it very simplistically explains how traveling at high speeds slows your time respectively. So in essence, you are traveling into the future by approaching such speeds. This empirical thought is backed up by satellite clocks that need to adjust themselves due to their orbit in space.

However at the same time this video states:
http://www.youtube.com/watch?v=JPk7imosxRg&feature=related
Skip to 7:28. In this video, it explains that as you approach the speed of light, by Einstein's theory of relativity it is Albert's stationary rocket that is moving. Thus, his "light clock" takes a longer time to hit each mirror in Bertand's relative position. Following this logic, as Bertand approaches the speed of light, Albert's "light clock" would stop all together, and in fact go back in time if Bertand breaks the speed of light.

My question is simply how do these contradictory theories coexist? How can traveling at speeds approaching the speed of light send you into the future and simultaneously into the past? This cognitive dissonance hasn't been fully explained where I looked, so hopefully I will have some answers here.

 

[LeonhardEuler]

Your question is a good one. It can be restated another way. If two observers are moving relative to each other, they both think that time is moving more slowly for the other. Who is right? If they meet again, who will be older?

This is known as the twin paradox, and it has been a well known counter-intuitive result of the theory of relativity since the beginning of that theory. Rather than going into a long explanation, you can read about it: http://en.wikipedia.org/wiki/Twin_paradox

 

[Entropia]

Firstly, it is important to note that the concept of time travel is still a theoretical concept and has not been proven to be possible. Einstein's theory of relativity, specifically the special theory of relativity, does provide a framework for understanding how time and space are interconnected and how they can be affected by speed and gravity.

One of the key principles of special relativity is that the laws of physics should be the same for all observers, regardless of their relative motion. This means that if two observers are moving at different speeds, they should still measure the same speed of light. This is where the concept of time dilation comes in - as an object approaches the speed of light, time will appear to slow down for that object in relation to a stationary observer. This is why satellites in orbit experience time dilation and need to adjust their clocks accordingly.

However, as you mentioned in the video, there is also the concept of the "twin paradox" where one twin travels at high speeds while the other twin remains stationary. The twin who travels at high speeds will experience time dilation and will age slower than the stationary twin. This can create the illusion of time travel into the future.

But when we consider the idea of traveling faster than the speed of light, we enter the realm of general relativity. According to this theory, as an object approaches the speed of light, its mass increases and it would require an infinite amount of energy to accelerate it to that speed. This is why it is currently believed that it is impossible to travel faster than the speed of light.

Furthermore, if we were to assume that it is possible to travel faster than the speed of light, it would also mean that we are breaking the laws of causality - the principle that an effect cannot occur before its cause. This is why the idea of time travel into the past is often considered to be a paradox and is still a subject of debate among physicists.

In conclusion, the theories of relativity and time travel are complex and can seem contradictory at times. It is important to remember that they are still theories and not proven facts. The concept of time travel, especially into the past, is still a subject of research and debate in the scientific community. It is possible that our understanding of these theories may change as we continue to explore and experiment with them.