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tyracandelaria · Nov 22, 2012, 12:04 PM

If one was to build a time machine why is it that some peoples theories say that it will only work within the time it was built. How can you travel further back then the time machine was built. Would you use as a communication device to send a message if you were to speak into the past? Could you communicate with sound how would you calculate the time you would go. How would you turn it off and on.

Wondergirl · Nov 22, 2012, 12:21 PM

I have no idea. Certainly you must have some ideas already, since you are even posing these questions. Is this for a school project or an assignment?

Alty · Nov 22, 2012, 04:14 PM

There's no way to give a scientific response, which would be based on facts, on something that isn't factual.

Basically, when it comes to time travel, there are no rules. You can make up whatever you want, because it's not possible. So anything goes.

TUT317 · Nov 22, 2012, 11:17 PM

Hi tyracandelaria,

I think the short answer to your first question is that it is logically possible to travel back in time to point in time before your time machine was invented.

The important point is that it is LOGICALLY POSSIBLE. This DOES NOT mean that it is ACTUALLY POSSIBLE. Your other questions can also be investigated in terms of LOGICAL possibilities. Invariably these questions will involve addressing a number of paradoxes.

Tut

Fr_Chuck · Nov 23, 2012, 01:31 AM

Those that follow time travel will believe normally that time travels in waves, and are at a regular basis. So to judge and calculate those waves will allow a person to know how far.

The issue is that to communicate one would have to either leave a path way open which is not normally a expected event. The way to estimate time will be of course temporal time in the travel event.

joypulv · Nov 23, 2012, 05:55 AM

Your questions will take your lifetime to answer, probably. Good luck.

With no knowledge of theoretical physics, I see a 'time machine' as being simply a space ship that goes faster than the speed of light and comes back to earth. Or at least that will be the first step. Maybe rearranging molecules and speeding them around might be next.

As for communicating with and changing the past, those are topics that entertain many a theoretician. There's even some good movies on the subject. My favorite question is how can you change the past without changing the present that allows you to even exist?

TUT317 · Nov 23, 2012, 06:09 AM

Originally Posted by joypulv

Your questions will take your lifetime to answer, probably. Good luck.

With no knowledge of theoretical physics, I see a 'time machine' as being simply a space ship that goes faster than the speed of light and comes back to earth. Or at least that will be the first step. Maybe rearranging molecules and speeding them around might be next.

As for communicating with and changing the past, those are topics that entertain many a theoretician. There's even some good movies on the subject. My favorite question is how can you change the past without changing the present that allows you to even exist?

Your first reference is to time dilation and special relativity. So yes, it is actually possible to revisit the earth as it exists in the future.

I think your second reference is to the grandfather paradox. If you could go back in time and kill your grandfather is it possible to continue your existence? The answer seems to be no, but there are ways of getting around this problem. In theory that is.

Tut

ScottGem · Nov 23, 2012, 07:06 AM

Originally Posted by TUT317

So yes, it is actually possible to revisit the earth as it exists in the future.

Really? Can you prove that?

As has been pointed out, since no one has ever done it, anything about time travel is theory. I don't think anything has been proven one way or another about it.

So until you can prove something making statements about what is and isn't possible, doesn't make sense.

joypulv · Nov 23, 2012, 08:21 AM

We don't really know that no one has ever done it... and no, I'm not talking about ancient visitors. I'm just sayin' we don't know. For all we know someone on these very boards is from the future, and isn't eager to tell us. Of course you could argue that that means it hasn't been done yet. So I can say that someone on these boards has made many visits to the past...

We don't 'know' that the Egyptians who built the pyramids had a thorough knowledge of astronomy, including precession of the planets, and of the sun being the center of our solar system (other cultures seem to have had that knowledge too), but we have no 'proof' and so ascribe such knowledge to later scientists.

ScottGem · Nov 23, 2012, 01:36 PM

Good point. Let me restate, no one has come forward with proof that they have done it.

Alty · Nov 23, 2012, 02:48 PM

All I know is that if you use your DeLorean to go far into the past, make sure you bring enough plutonium to get back, and don't let your mother fall in love with you. :)

joypulv · Nov 23, 2012, 03:36 PM

Oops, won't let me appreciate Alty's response, LOL.

Now I'm all curious about how to get around killing my grandfather..

Wondergirl · Nov 23, 2012, 03:42 PM

In The Mirror by Marlys Millhiser, "a 20-year-old Boulder girl stares into her grandmother's Chinese mirror on her wedding day in 1978, faints and comes to in her grandmother's body--in 1900--about to be married to a miner. As she moves through life, even giving birth to her own mother, she becomes known as a fairly decent seer. Had she paid more attention in school, she would have been a great one." (Amazon)

TUT317 · Nov 24, 2012, 12:27 AM

Originally Posted by ScottGem

Really? Can you prove that?

As has been pointed out, since no one has ever done it, anything about time travel is theory. I don't think anything has been proven one way or another about it.

So until you can prove something making statements about what is and isn't possible, doesn't make sense.

Time dilation has been proven by numerous scientific experiments going back as far as the 1970's. Subsequent experiments since have confirmed the findings.

See the following link.

http://www.hyperphysics.phy-astr.gsu...iv/airtim.html

This is also why global positioning satellites need to be adjusted on a regular basis. Time passes slower at altitude ( relative to sea level).
Tut

ScottGem · Nov 24, 2012, 06:51 AM

Your statement was that it is possible to revisit the earth in the future. How does time dilation prove that?

TUT317 · Nov 24, 2012, 02:15 PM

Originally Posted by ScottGem

Your statement was that it is possible to revisit the earth in the future. How does time dilation prove that?

The velocities we are able to obtain in out world only represent a fraction of the speed of light. Nonetheless, time dilation has been reproduced experimentally. Even the Space Shuttle orbiting the earth at about 8 k.p.s represents about 0.0000300 the speed of light. Even if the Shuttle orbited the earth for a year this would still only represent a time dilation of about 5 nanoseconds.

Therefore, upon returning from my Space Shuttle journey I would find to my amazement (compared to my atomic clock) all the atomic clocks on earth had gained 5 nanoseconds.

There are of course a number of ways to interpret the data. One of those ways is to say that the Shuttle pilot, upon returning to earth has done so 5 nanoseconds into the future.

The reason I said that it is possible to revisit the earth in the future is because I support a particular interpretation of the data available.

Tut