Seriously thoughtful The concept of 'TIME'

[Williamlk]

I'm starting this topic based upon a show I recently saw discussing how theoretcally time travel is possible.
I've long been interested in the concept of time. Is time real? Is it just an illusion?

I was wondering if anyone has read anything that discusses these implications, or wants to weigh in with an opinion.

[Anarel]

Haven't read anything about time recently (maybe look up some philosophical works?), but I once read somewhere that it's never going to be possible to go back in time, but it might one day be possible to go forwards...

[Solitaire1]

Originally Posted by Williamlk

I'm starting this topic based upon a show I recently saw discussing how theoretcally time travel is possible.
I've long been interested in the concept of time. Is time real? Is it just an illusion?

I was wondering if anyone has read anything that discusses these implications, or wants to weigh in with an opinion.

I enjoy time travel stories, and I'm currently reading a comic book (Booster Gold) where time travel and keeping history intact is the central point of the series.

As far as time itself, I think of time as the fourth dimension, on par with height, length, and width. I base this on the requirement for existance, meaning that in order for an object to exist it must have all four dimensions. If you set any of the four dimensions of an object to zero, then an object can't exist.

I think the reason time seems different from the other dimensions is that our consciousness operates along it. Also, we have an ability to move in the three physical dimensions under our own power, but we are basically stuck in the stream of time without an ability to alter our rate of travel or our direction of travel. Via technology it is possible to alter our rate of travel forward in time (such as accelerating to near the speed of light) but we are basically limited in what we can do.

When considering the possibility of time travel, I think that travel into the future might be possible. One factor in its favor is that it doesn't have to deal with the issue of time paradoxes. As far as methods to accomplish this, one simple way is via the use of some type of status (such as cryogenics) where you are basically put on hold and then released when you arrive at your destination.

More complicated is travelling backwards in time. This is when you have to deal with the issue of time paradoxes such is if you travel into the past and change history in a way where you suddenly couldn't exist yet you had to to make the change in history.

In many of the stories I've read, one way to deal with this is the branching timelines theory (this is my favorite theory). When you make your first trip through time you disappear from your native timeline and the timeline splits at the point where you departed and the point where you arrive. In one branch you didn't arrive, and in the other you did arrive. At that point, you can never return to your original timeline (from the point of view of someone there you just disappeared) and you can't eliminate yourself even if you travel back into the past and kill yourself. Your personal timeline becomes like a line of string that connects all of the points that you jumped from and to.

Just my thoughts and opinions, thanks for reading.

Originally Posted by Anarel

but it might one day be possible to go forwards...

I am continually travelling forward in time second by second and will do until the moment I die and even then I will continue to do so.

Look just did it again.

[Sparrow]

I remember reading that the totalled velocity of anything through four dimensional spacetime equals the speed of light.
If you're at rest with regard to three dimensional space; you're travelling at lightspeed through time. If you start moving in three dimensional space, your speed through time slows down - such that your total velocity is always the speed of light. So, you can alter your speed through time, but you can't go into reverse (I think ).
And photons, which travel at the speed of light, don't 'experience' time.

Stephen Hawking 'proved' travelling back in time is impossible. He sent an invitation out asking time travellers from the future to attend a party - but no-one showed up .

[montsnmags]

As this is "unrelated to e-books", I have moved this thread here, to The Lounge, and added the "Seriously Thoughtful" tag. I'd encourage and look forward to seriously thoughtful responses, as guided by the OP.

Cheers,
Marc
Moderator

[MickeyC]

[QUOTE=Sparrow;1067735]I remember reading that the totalled velocity of anything through four dimensional spacetime equals the speed of light..[/QUOTE\])

I've read the same thing; your speed through time and your speed through space together equals the speed of light. Consequently, if your speed through space increases, your speed through time has to slow down. This because it's against the law to go faster than the speed of light: thus time dilation.

A very good book on the subject is Einstein's Cosmos by Michio Kaku. In it, the author does a better job of explaining how Einstein concluded that, since the speed of light is constant, regardless of the speed of the observer, that the observer must be slowing down in time the faster he/she goes. And this has been proven using atomic clocks on airplanes and comparing them to atomic clocks on the ground.

Kaku also goes easy on the math and mixes Einstein's science in with his life thus making for an excellent read.

There Marc, we've mentioned a book. Are we out of trouble now?

[montsnmags]

Originally Posted by cassidym

...

There Marc, we've mentioned a book. Are we out of trouble now?

There's no "trouble".

It was in General Discussions, which is generally "about e-books" (e-books as a topic) rather than about a particular e-book (which is somewhat unlimited in scope). Whereas The Lounge allows for all other "Friendly...discussion unrelated to e-books".

Adding the "Seriously thoughtful" was just to add a slight aversive measure against hijacking and "Unutterably Silly" frivolity. The topic and tone can, of course, be guided by the OP.

Cheers,
Marc

[kindlekitten]

I thought EInstein had come up with the math that proved it possible.

[Sparrow]

The best novel I've read on resolving the apparent paradoxes of time travel is Stephen Baxter's brilliant "The Time Ships" .

[devilsadvocate]

There are 2 fundamental issues with the whole idea.

One, everything in Einstein's theory of Special Relativity is based on relative frames of reference; that is, there is no point in the universe which is completely stationary, and everyone has the right to call the shots based on "their" frame of reference. For instance, if train X is moving toward train Y then to the passenger on train Y it would appear thus, but to a passenger on train X it would appear that train Y is moving toward them.

Special Relativity is comprised of 2 postulates: One says that the laws of physics are true for all frames of reference. The other says that based on this, the speed of light is the same in all frames of reference. Here's where it gets goofy...this means the speed of light is the same no matter what speed the object generating it is moving. If someone throws a ball from train X at train Y at, say, 30 MPH, then the ball itself would be traveling at 30MPH plus whatever speed the train is doing, so if that train is going 50, then the ball will hit you at 80 MPH (ouch!)

With this in mind, you'd think the light (which travels about 670,000,000 MPH) coming from the front of the train would be going 670,000,050. HOWEVER, the second postulate of Einstein's theory says that isn't the case; the light is still going 670,000,000MPH regardless. Remember that speed is distance x time; then remember that whole frame-of-reference thing in the first paragraph...the way we measure it is the problem, which leads me to the second issue with time travel.

Hasn't anyone stopped to consider the idea that time is a uniquely human invention? It's in our nature to measure things; it's how we orient ourselves in the universe. We need to know "when" something happened--or will happen--therefore we need a scale on which to place events relative (there's that word again) to each other. Think of it this way: Would a tree measuring 30m still be 30m tall if humans weren't around to measure it?

Think about that for a second...or however long you like, since this is about time

Yes, the tree would still be the same height, but would it be 30m? Put another way: Yes, the dinosaurs would have become extinct at the same point in time, but if we weren't here to measure that period of time (much less develop the technology to determine it), it would be just another event that happened after something but before something else.

To me--from my frame of reference, if you will--the pursuit of a unification-theory of time and space resembles that of Zeno's Paradox, wherein science will get closer and closer, but technically never get there.

[TGS]

Originally Posted by kindlekitten

I thought EInstein had come up with the math that proved it possible.

If he came up with anything it was the maths that proved it impossible.

I was wondering if anyone has read anything that discusses these implications,

Best thing I've read recently is Images of Time by Robin Le Poidevin - which is more to do with how we represent time but the early sections present a good summary of some of the problems involved in thinking about time,

[beppe]

I do not think there is a simple way to illustrate the bounds and limits of time-space at the light of the theory of relativity.
For who might be interested there is this voice on Wkipedia that might give a succint introduction. It immediately becomes abstract and mathematical.

Either one knows or not.

Speculating about it in a SF context, that can be a lot of fun, and also to reflect on the perception of time, both personally in the flow of our life, and historically, how time was conceptualized, before about 100 years ago.

[Sparrow]

Originally Posted by devilsadvocate

Hasn't anyone stopped to consider the idea that time is a uniquely human invention? It's in our nature to measure things; it's how we orient ourselves in the universe. We need to know "when" something happened--or will happen--therefore we need a scale on which to place events relative (there's that word again) to each other.

I don't understand why the idea of time would be 'uniquely human', since other species share the same needs. A squirrel buries nuts knowing they will be there in the future.

I agree the scales use to measure stuff are human inventions - but I don't think the stuff is.

As the American scientist John Wheeler pointed out, time is what stops everything happening at once.

http://www.abc.net.au/science/bigquestions/s460740.htm

[bjones6416]

Originally Posted by Sparrow

I agree the scales use to measure stuff are human inventions - but I don't think the stuff is.

Interesting idea. You're right, I think.