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Is time travel possible??


Rajnish Kaushik

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!

Moderator Note

If you wish to ask a question on the physics of potential time travel - is it forbidden? is it likely? can we do it? then please do so - but the main fora are not the place for a few frames of a film from youtube claiming to show a time traveller. That sort of post belongs in the lounge or speculations if it must be posted - after all this is science forum not a conspiracy website.

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The Internet is a very strange place where some people post a photoshop as a joke, then the joke becomes (mis)information. Along with photoshopped time travelers one can find giants and ufo's and other Bad Science (keep the initials and throw out the rest).

Never, NEVER trust images from the Internet.

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!

Moderator Note

Rajnish,

Staff have been very patient with you because we understand that you are young, but you seriously need to start listening to us. A few points:

- The purpose of SFN is to operate as a place for discussion. Your tendency to post single word posts, or a few words that have little to no relevance to the OP run counter to that purpose. Please stop making posts that consist of little more than, 'ok :(' or, 'thnx bro,' or, '???' They are both pointless and irritating to read.

- Following on from above, if you wish to start a thread! could you at least attempt writing a full paragraph outlining what you wish to ask and your thoughts on the matter. This is especially important for your numerous homework threads.

- If staff ask you to do something as staff members, do it. Imatfaal just requested that you spend your next post forming your question to explain why you posted those images above. That means writing out a couple of sentences, not posting more pictures. I suggest you do this now or we will be closing this thread.

- Please start posting your threads in one forum only and in the correct one. If you are unsure of where to put a thread, PM a staff member. We're getting sick of moving and closing / hiding your threads.

- Try and make an effort to search for things before you ask questions. You'll find a lot of topics have already been asked and answered quite well here or somewhere else on the internet and you may not need to ask your question at all. This thread is an example of that, weird images notwithstanding. It will also help with your homework threads.

Finally, please for the love of God do not respond to this note with an 'ok' and an emoticon. In fact, don't respond to it at all. If you have any questions about this note, report the post (using the grey-blue link near the Multi-quote button) or PM a member of staff.

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they are good are they true?

 

The first paragraph on that page says: "All of these reports have turned out either to be hoaxes or to be based on incorrect assumptions, incomplete information, or interpretation of fiction as fact."

 

So no, they are not true.

Edited by Strange
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Rajnish

 

You have been asked very nicely, in this thread and others, to pay a little more attention to the way you post and to perhaps think a bit more before hitting the reply button.

 

So if someone says

Also, the clue is in the title: "urban legends"

Before posting a follow up question why not try googling "urban legends"? If you do not understand a phrase that the other members clearly do understand your first step should be to consult google /wikipedia - ie the following

 

https://www.google.co.uk/search?q=urban+legends

http://en.wikipedia.org/wiki/Urban_legend

 

No one minds answering questions - but it can get tiresome when it seems that the question is being asked to avoid a minute's research on the internet. There is no need to respond to posts within seconds - it is much better to take a few moments to compose a better reply; try to write in full sentences (it is good practice), quite a lot of us are not teenagers and text-speak/bro etc can be off-putting, and make it clear to the other members that you are fulfilling your side of the discussion before expecting them to take the time to respond.

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really?

i was fulled by you tube sad.png

 

That is hardly surprising. That is one reason why YouTube is not considered a reliable source of information.

 

And yet so many people with their "personal" theories seem to rely on it ...

Edited by Strange
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ok i will take care of it from now onward

smile.png

time travel happens all the time. this is because time slows down as you speed up. this effect is also seen in gravitational fields. thank einstein for forward time travel. traveling backwards in time is a different story. consider feynman's idea of the positron. you may want to do research on that. it will keep you busy for a moment.

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time travel happens all the time. this is because time slows down as you speed up. this effect is also seen in gravitational fields. thank einstein for forward time travel. traveling backwards in time is a different story. consider feynman's idea of the positron. you may want to do research on that. it will keep you busy for a moment.

Time travel into the past is impossible. The positron is just something that behaves the opposite of the electron. It doesn't mean it is time travel into the past.

In special relativity, the equation for relative time is [latex]t=\tau \sqrt{1-\frac{v^2}{c^2}}[/latex]

We don't use the actual velocity, but we use the relative velocity. The relative velocity would be velocity respect to another observer. If the other observer had velocity u, and you had an actual velocity of v', your velocity relative to them and their velocity relative to you would be

[latex]v=\frac{v'+u}{1+\frac{v'u}{c^2}}[/latex]

The effects of special relativity only take effect at velocities comparable to the speed of light. At everyday velocities, the effects of special relativity are very small.

In gravitational fields, [latex]t=\tau \sqrt{1-\frac{R_s}{r}}[/latex] in a Schwarzschild space-time. The effects are negligible for everyday life, as we don't change our distance from the center of the earth very much.

Time travel is impossible in everyday circumstances.

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