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# Does this prove that time travel is impossible?

1. (Original post by oh_1993)
I came up with an idea. In an infinite amount of time, everything that is possible happens. This means that if time travel is possible, it will eventually be discovered and used to travel back in time to a time before the present day.

But in an infinite amount of time, everything that is possible will happen an infinite amount of times so an infinite amount of people will be travelling to an infinite number of locations at an infinite number of times. That would mean that there would be an infinite number of people entering every possible location on Earth in the present day, which clearly is not the case.

We would be connected with people on an infinite time span everywhere. And if it is possible then given infinite opportunities it will happen infinite number of times!

Please tell me what you think. Thanks
Ah, here is the problem, time is not infinite. As they know that time is not constant and can be changed, this also means it can have a start and an end.
2. Has nobody seen that documentary back to the future?
3. Wait, I thought the Kardashians were time travellers...
4. (Original post by oh_1993)
I came up with an idea. In an infinite amount of time, everything that is possible happens. This means that if time travel is possible, it will eventually be discovered and used to travel back in time to a time before the present day.

But in an infinite amount of time, everything that is possible will happen an infinite amount of times so an infinite amount of people will be travelling to an infinite number of locations at an infinite number of times. That would mean that there would be an infinite number of people entering every possible location on Earth in the present day, which clearly is not the case.

We would be connected with people on an infinite time span everywhere. And if it is possible then given infinite opportunities it will happen infinite number of times!

Please tell me what you think. Thanks
First: Time might be infinite but as far as I know the Earth is going to be gone in about 2 billions of years. That means that time for us (not for the rest of the universe) is not infinite.

Second: Your whole idea is based upon the assumption that our existence in the universe is infinite or rather, on your confusing, infinite time in the universe with humankind (as a species) existing forever (hence infinite time).

Since your whole idea is based on the assumption that humans will live forever and that is probably not the case, your whole ideas breaks down.

P.S. Check this: 1950, "Rotating Universes in General Relativity Theory." Proceedings of the international Congress of Mathematicians in Cambridge, 1: 175–81. Godel (Einstein's close mate) made a discovery that theoretically would allow time travel to happen. It has been 62 years since then, and no one has been able to refute his discovery. So for what we know so far time travel is a real possibility. The construction of a time machine is a whole different matter.
5. (Original post by StuAndMma)
You think too much.
Correct. Never done me any harm though. Yet....
6. (Original post by Raiden10)
Why?
The probability of flipping an unbiased coin and getting tail is 0.5

Mean = number of times flipped x probability (because the probabilities are independent)

In an infinite amount of time it is flipped infinite times therefore mean will be infinite.

Also, assuming the lottery to be fair, if you were to live forever and buy a ticket every week you would eventually win.
7. (Original post by Simplicity)
Semantically speaking what you are implying is incorrect. Something having a probability of 0 doesn't imply that it won't happen.

Picking a real number at random has probability zero for each number. But, that doesn't stop me saying 1 even through the probability of me picking 1 out of all the real numbers is 0.
Wouldn't that mean that the probability of picking 1 would be 0 but the probability of saying 1 would be between 0 and 1? They are different things. So it is still impossible for you to pick one. It is still impossible to pick pi off a number line to an infinite number of decimal places hence p=0 but obviously you can say 'pi'. lol
8. (Original post by oh_1993)
The probability of flipping an unbiased coin and getting tail is 0.5

Mean = number of times flipped x probability (because the probabilities are independent)

In an infinite amount of time it is flipped infinite times therefore mean will be infinite.

Also, assuming the lottery to be fair, if you were to live forever and buy a ticket every week you would eventually win.
If I pick a random prime the probability of it not being 7 is 1. The probability of it not being 8 is also 1. But one of these eventualities is inevitable, and the other is not.

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