What I've seen and learned do not correspond with the members here

[QuantumTheory]

Everyone tells me here, time travel is not even *theortically* possible. Some scientist are bold and say time traevl to the future IS possible. I don't understand why no one here even accepts it as a theortically possbility? Physics allows it, and I don't have a PhD in physics but according to special relativity if it was possible to get close to the speed of light you would travel into the future relative to the people on Earth are those speeds. The problem is getting to those speeds, as light travels at 186,000 MPS and the fastest we've gone is about 20,000 MPH

Seriously, why doesn't anyone here agree with it? Is Frank Tipler a hoax? I Find it pretty funny how people tell me the Science Channel is wrong on all of its channels. It has a lot of facts, right ones at that, sure, it may be to the laymen people, but whatever.

Frank Tipler said if you were to rotate a massive object it would bend time and you may be able to travel into the past. There are also hypotentical cosmic strings.

Is Frank Tipler, PhD some type of psuedo Jack Thompson wacko?

I just don't understand , I just search in time travel, I see valid scientific facts (Not the hoax ones) that it IS possible, yet many people here are very smart people with PhD degreees and scientist and everyone degrees. In fact, I can't find a single person to admit its a theortically possbility at best. (Or that physics allows it)

Even stephen hawking in his "Brief history of time' mentions it may be possible. Yet people want me to quote the book, I don't even have it, but I read it.

 

[Chi Meson]

Tipler is a professor at Tulane University, so I am not qualified to pronounce him a crackpot. I can quite easily state, however, he is at the very least a fringe element in theoretical physics; he also has a very clear agenda and therefore a bias toward one way of thinking.

Tipler is attempting to bring theology and science together. Google "Omega Point," for one to get a clear idea of his worldview.

It is clear that his ideas are NOT accepted by the larger community. Could he be right? Sure, but most physicists don't think so.

For a more acceptable theoretical conditions for time travel, research Kip Thorne. He has a mathematical model for creating quantum tunnels, but even he admits it would require an impossible to acquire "negative energy density."

Edit:
Here's a link to an article on "negative energy."
http://www.physics.hku.hk/~tboyce/sf/topics/wormhole/wormhole.html
Here's Tipler's defense of his "Omega Point Theory."
http://home.worldonline.nl/~sttdc/tipler.htm

This is a quote from Tipler in that article:
" This is a question of physics, not mathematics. However, until an experiment - and only an experiment - shows quantum mechanics to be wrong, I shall assume quantum mechanics to be right."

Such an attitude is specifically non-scientific.

 

[Tarheel]

In before lock!

Try using the phrase "Date Altering Journey".

If you say "Time Travel" on this message board the thread is locked as soon as a moderator spots it.

 

[vanesch]

Google "Omega Point," for one to get a clear idea of his worldview.
It is clear that his ideas are NOT accepted by the larger community. Could he be right? Sure, but most physicists don't think so.

Yeah, I even spend some money on buying one of his books. Nevertheless, I think that with the right mindset, Tipler IS great reading. That mindset is "speculative mode ON'. I don't see what's wrong with, starting from what one knows today, and extrapolate it beyond what is "reasonable", to explore the consequences. Even adding a few reasonable or unreasonable hypotheses is, to me, not unallowed for, as long as you keep in mind that you are EXTRAPOLATING and hence speculating.

This is a quote from Tipler in that article:
" This is a question of physics, not mathematics. However, until an experiment - and only an experiment - shows quantum mechanics to be wrong, I shall assume quantum mechanics to be right."
Such an attitude is specifically non-scientific.

Well, I disagree. At most you should put a caveat that you are using quantum mechanics according to its axiomatic foundation, but outside of its empirically tested scope. WITH that caveat, I think it is the most reasonable form of speculation, no ?

However, don't go thinking that I now claim that Tipler is RIGHT. Tipler is SPECULATING. But his speculation is informed and based upon an extrapolation of currently accepted physics ; in fact his speculation is much less extreme than the speculation in spin foams, or string theory. It is "informed science fiction". Sometimes it can be fun to do so, be it just to see what ARE some of the consequences of the current axiomatic system we call "conventional physics" (ok, with some extra hypotheses). It is much better speculation than, say, Star Wars or so. And as all this stuff is in any case for the entertainment of the mind, and nothing else.

 

[Aether]

In before lock!
Try using the phrase "Date Altering Journey".
If you say "Time Travel" on this message board the thread is locked as soon as a moderator spots it.

This message board is all about trying to understand mysterious phenomena. If you post a copy of tomorrow's newspaper (today), and ask "how did this happen?", then we would definitely have something to talk about. However, there isn't any time travel phenomena to talk about since nobody is claiming to have any evidence of such a thing. To talk about whether or not time travel is theoretically possible is something that the "Special and General Relativity" forum might have something to say about, but that would be a highly technical discussion.

 

[Doc Al]

Everyone tells me here, time travel is not even *theortically* possible. Some scientist are bold and say time traevl to the future IS possible. I don't understand why no one here even accepts it as a theortically possbility? Physics allows it, and I don't have a PhD in physics but according to special relativity if it was possible to get close to the speed of light you would travel into the future relative to the people on Earth are those speeds. The problem is getting to those speeds, as light travels at 186,000 MPS and the fastest we've gone is about 20,000 MPH

This so-called "time travel" to the future is a commonly accepted consequence of special relativity. Why do you say that "no one here" accepts it?

I agree with Chi Meson that Tipler has his own off-the-wall, highly speculative agenda. I wouldn't take him seriously.

 

[vanesch]

If you say "Time Travel" on this message board the thread is locked as soon as a moderator spots it.

Depends on the moderator

If you go around claiming that you are building a machine to travel to the middle ages in your basement, and you ask for credits here, yeah, it will be locked. If you claim that people at NASA are idiots, because they don't want to use your superduper theory on time travel, probably too. However, if you are asking what is the theoretical status of "time travel" in modern physics, I don't see why it should get locked.

In GR, nothing prevents from having topologies which contain "closed timelike curves (CTC)", except a POSTULATE from Hawking, which states: "we don't want to see CTC". The reason for that is of course that it clashes with an idea of causality that we have, and that could lead to a paradox. It is exactly the same idea that tells us that information on which we can base decisions, cannot travel faster than light in special relativity.

The paradox is the following:
at time t1, I receive a signal (A or B). I make a device that upon reception of signal A, sends out signal B, and vice versa at time t2 > t1. If this signal can now travel around a CTC, and arrive back at t1, then we clearly have a logical contradiction. If it was signal A, then B was sent out, but then we should have received B, not A! And if it was signal B, then A was sent out, but then we should have received A, not B.

Now, quantum theory could alter this picture, if "multiple worlds" are somehow allowed, so the strictly logical paradox disappears.

Nevertheless, the MAIN reason why CTC are not considered seriously, is simply, that we do not seem to NEED them. There seems to be no empirical indication that things do follow CTC's. Does it mean that they are strictly forbidden ? Or does it mean that they are a possibility, but that they don't appear in our universe ? Again, just material for the entertainment of the mind !

 

[fargoth]

Everyone tells me here, time travel is not even *theortically* possible. Some scientist are bold and say time traevl to the future IS possible. I don't understand why no one here even accepts it as a theortically possbility? Physics allows it, and I don't have a PhD in physics but according to special relativity if it was possible to get close to the speed of light you would travel into the future relative to the people on Earth are those speeds. The problem is getting to those speeds, as light travels at 186,000 MPS and the fastest we've gone is about 20,000 MPH
Seriously, why doesn't anyone here agree with it? Is Frank Tipler a hoax? I Find it pretty funny how people tell me the Science Channel is wrong on all of its channels. It has a lot of facts, right ones at that, sure, it may be to the laymen people, but whatever.
Frank Tipler said if you were to rotate a massive object it would bend time and you may be able to travel into the past. There are also hypotentical cosmic strings.
Is Frank Tipler, PhD some type of psuedo Jack Thompson wacko?
I just don't understand , I just search in time travel, I see valid scientific facts (Not the hoax ones) that it IS possible, yet many people here are very smart people with PhD degreees and scientist and everyone degrees. In fact, I can't find a single person to admit its a theortically possbility at best. (Or that physics allows it)
Even stephen hawking in his "Brief history of time' mentions it may be possible. Yet people want me to quote the book, I don't even have it, but I read it.

"time travel to the future"?
isn't that what youre doing right now?
we travel time to the future all the time its traveling backwards that can't be done.

seriousely, why spend so much energy on flying near the speed of light, when you can just freeze youreself and wake-up somewhere in the distant future... i see no difference.

 

[Ivan Seeking]

We just went through this QuantumTheory

My best understanding is that there are solutions to the equations of General Relativity that appear to allow for time travel, however, practical considerations as well as deeper complications may render time travel impossible. At this time there is no consensus among physicists what the correct answer to all of this may be, but the nay crowd seems to have a larger population than the yay crowd. My opinion is that without a unified theory this is all speculation at best. For all that we know, we may not have even identified all of variables needed for such a theory.

If any Mentors wish to correct or modify [add to] this statement, please go ahead. If any of our physics gurus wish to comment, please send me a PM. I am closing this to prevent inappropriate speculation.

https://www.physicsforums.com/showthread.php?p=867661#post867661

The next thread like this that you start will be deleted and you will be penalized for annoying behavior.

Your interest is appreciated but we can't allow wild speculation. The final answer at this time is that we just don't know - nobody does. Many of us hope that such things are possible, including me.

 

[Ivan Seeking]

"There's a solution of the equations of general relativity called the Aichelburg-Saxl solution, which describes massless black holes moving at the speed of light. There's no experimental evidence that these actually exist, but they're fun to think about nonetheless, since you can use the equations of general relativity to figure out what they would do if they did." – Dr. John Baez