Traveling at the speed of light and time travel?

In summary, the conversation discusses the concept of time dilation and whether time would completely stop for an observer traveling at 100% the speed of light. It is explained that time is relative and only slows down relative to those moving slower, and light always travels at the speed of light regardless of the observer's speed. The conversation also addresses common misunderstandings about Special Relativity and the consistency of the speed of light in different frames of reference.
  • #1
Dieterich
2
0
I understand that modern day Physics allows for travel into the future, but not the past. I understand that time slows down the closer and closer you get to the speed of light, so that you never exceed that limit. But what if you meet it? I know because of the laws of Physics, you couldn't meet it, only 99.99% of it, but what if you reach 100% the speed of light?

I understand this violates the currently accepted laws, but would time completely stop for the observer traveling at 100% the speed of light? Because any slight movement of the hand, or head or any ligament would then exceed the limit...


Again, correct me if any of my understanding is wrong, I'm relatively new to Physics and I really enjoy it.
 
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  • #2
Dieterich said:
I understand that time slows down the closer and closer you get to the speed of light, so that you never exceed that limit.

Time is relative. It only slows down relative to people moving slower than you. You would perceive time to go on as normal.

what if you reach 100% the speed of light?

It doesn't really make sense to ask such a question. "What would the law of physics be like if there were no laws of physics?" My point is that you cannot use physics to analyze a situation in which the laws of physics do not hold. You would need a whole new theory to describe it!

That's not to say that you shouldn't ask the question, just that there is no answer that people can give you given our current knowledge of physical laws. Indeed, it is questions like these that tend to inspire new ideas in physics.
 
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  • #3
Dieterich said:
I understand that modern day Physics allows for travel into the future, but not the past. I understand that time slows down the closer and closer you get to the speed of light, so that you never exceed that limit. But what if you meet it? I know because of the laws of Physics, you couldn't meet it, only 99.99% of it, but what if you reach 100% the speed of light?

I understand this violates the currently accepted laws, but would time completely stop for the observer traveling at 100% the speed of light? Because any slight movement of the hand, or head or any ligament would then exceed the limit...


Again, correct me if any of my understanding is wrong, I'm relatively new to Physics and I really enjoy it.

Your understanding of basic Special Relativity is wrong. When you move, your time doesn't slow down. For example, do you see your time slowing down? After all, according to the creatures on Alpha Centauri, you are moving. Do you see any time dilation effects?

If A moves relative to B, B will see A's time "slowing down". But it works the other way around as well. Since there's nothing special about B, one can also be in A's frame, and A can see that B is moving. A will see B's time slowing down. But both A and B sees no difference in their own respective time.

This is one of the most common mistakes of anyone who misunderstood Special Relativity.

Zz.
 
  • #4
Dieterich said:
I understand that modern day Physics allows for travel into the future, but not the past. I understand that time slows down the closer and closer you get to the speed of light, so that you never exceed that limit. But what if you meet it? I know because of the laws of Physics, you couldn't meet it, only 99.99% of it, but what if you reach 100% the speed of light?

I understand this violates the currently accepted laws, but would time completely stop for the observer traveling at 100% the speed of light? Because any slight movement of the hand, or head or any ligament would then exceed the limit...


Again, correct me if any of my understanding is wrong, I'm relatively new to Physics and I really enjoy it.

What you should first understand is that if I see you traveling at 99.99% the speed of light, and you emit light in your forward direction, that light is traveling at the speed of light relative to you, and it is also traveling at the speed of light relative to me.

i.e. no matter how fast you go, light going in the same direction as you is always traveling at 300 000 m/s relative to you, whether you emit it or I do.
 
  • #5
Dr Lots-o'watts said:
What you should first understand is that if I see you traveling at 99.99% the speed of light, and you emit light in your forward direction, that light is traveling at the speed of light relative to you, and it is also traveling at the speed of light relative to me.

i.e. no matter how fast you go, light going in the same direction as you is always traveling at 300 000 m/s relative to you, whether you emit it or I do.

Taking into consideration what you said and as well as what ZZ said, if A is moving relative to B, and B emits light in a forward direction, will the light appear to slow down to A?
 
  • #6
Dieterich said:
Taking into consideration what you said and as well as what ZZ said, if A is moving relative to B, and B emits light in a forward direction, will the light appear to slow down to A?

Nope, the speed of light is constant from every frame of reference. They would observe the frequency of the light to be different though, due to the doppler effect and also time dilation/space contraction.
 

1. What is the speed of light?

The speed of light is approximately 299,792,458 meters per second in a vacuum. This is equivalent to about 670,616,629 miles per hour. It is the fastest speed at which all matter and information can travel in the universe.

2. Can anything travel faster than the speed of light?

According to our current understanding of physics, no. The speed of light is considered to be the ultimate speed limit in the universe. As an object approaches the speed of light, its mass increases and it requires an infinite amount of energy to reach the speed of light. This makes it impossible for anything with mass to exceed the speed of light.

3. How does traveling at the speed of light affect time?

According to Einstein's theory of relativity, time dilation occurs as an object approaches the speed of light. This means that time appears to slow down for the object in motion compared to an observer at rest. For an object traveling at the speed of light, time would essentially stand still.

4. Is time travel possible by traveling at the speed of light?

While time dilation does occur when traveling at the speed of light, it is not considered true time travel. This is because the traveler would still experience time passing normally for themselves, and they would not be able to travel back in time. Additionally, the amount of energy required to reach the speed of light is currently beyond our technological capabilities.

5. What is the concept of time travel?

Time travel is the idea of moving between different points in time, either forwards or backwards. It is a popular concept in science fiction, but it is currently not considered possible according to our current understanding of physics. However, some theories, such as the concept of wormholes, suggest that it may be possible in the future with advanced technology.

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