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Show ALL Forums  > Science/philosophy  > Time Travel-Is it possible?      Home login  
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 nipoleon
Joined: 12/27/2005
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Time Travel-Is it possible?Page 3 of 20    (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
If you could travel faster than the speed of light, you couldn't travel through time personally but you could see what the Earth looked like in the past.

Consider, you have a space ship which can travel four times the speed of light.

So, you get in your space ship and travel 2 light days away from the Earth. It would only take you 1/2 day to get there. When you turned back and looked at the Earth you would see Earth as it was 36 hours before you left. It took the light from Earth 2 days to travel what only took you 1/2 day.

Now get out your Tachyon Laser ( naturally you have one of those too ) which beems Tachyons at four times the speed of light and start beeming pictures of the 2 day old Earth back.
Since it only takes the Tachyons 1/2 day to travel 2 light days, the people back on Earth will see the Earth as it was 2 & 1/2 days ago.
Not 48 hours ago because 1/2 day would pass for the Earth to recieve the images.
 MikeWM
Joined: 2/7/2011
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Posted: 10/31/2011 8:53:30 AM
Tachyons are purely a theoretical particle though still arent they?

The idea though that anything can move faster than light if its assumed that time slows as you approach light speed is actually endlessly interesting

Would time in effect cease to move in either direction at lightspeed? If light speed was exceeded what then? Would you relatively speaking be travelling backwards through time?

If that is the case, and then if tachyons rather than theoretical particles did infact exist could they be in effect like a photon, but one generated by the future of the universe moving backwards in time

So in the same way we say if you were x light years from earth you can see the past, if you were x tachyon years from earth and could view tachyons would you then be able to see the future?
 nipoleon
Joined: 12/27/2005
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Time Travel-Is it possible?
Posted: 10/31/2011 10:38:20 AM
Tachyons are still theoretical as far as I know. I don't think anyone knows how much faster Tachyons would travel than light, considering they exist.

If you had a telescope with perfect resolution which would allow you to see details on a planets surface from any distance, then the further away from the Earth you got the further back in time you could see.
From 1000 light years away, you could see 1000 years into the past.
Maybe, there are alien civilizations who are right now observing the Roman Empire on Earth.

It would be easy to send a message to yourself in the future but not the other way around.
You could also simply write yourself a note, leave it in a deposit box, and wait for it.
 MikeWM
Joined: 2/7/2011
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Posted: 10/31/2011 12:33:05 PM
Yeah I get that

But as most of this is purely hypothetical anyway its claimed and infact to varying extents proven that the closer to light speed you go the slower your relative passage of time would be

So, that would give you a decreasing linear relationship of some gradient, which, if movement faster than light was infact possible could also theoretically continue decreasing and actually become a negative quantity

So is you took light speed to be a point where time was null, niether going forwards or backwards then progressing past light speed would/could mean the slope continues into negative time, and relative to the rest of space youre actually travelling backwards in time

More simply though, that would mean tachyons if they exist could potentially be doing that, so in the same way photons viewed one year from earth would show you what earth was like in the past, if you could view tachyons in a pictorial representation they "could" show you how something will look in the future, and fhe further from the object you are the further into its future you would be looking

I guess that would require that when a photon collides with something it would in effect create a new photon that is reflected/emitted from the surface plus a tachyon also

One heading forward in linear time at the speed of light, and the other going backwards in time but at more than the speed of light

Not in anyway claiming thats a "scientific" idea, just an interesting one you understand

And I guess rather than possibly clouding the statement by using the term "tachyon" something like antiphoton might be better
 nipoleon
Joined: 12/27/2005
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Posted: 11/1/2011 10:45:21 AM
Well frankly I doubt it.
Going twice the speed of light simply means you can go between 2 points in 1/2 the time a photon does. No matter how fast you go, you still can't get between point A and point B before you left.

Now, for traveling at very fast speeds some unusual things happen.

If you were in a space ship, traveling very fast, you don't notice any difference in the passage of time. But, if you look out the window, you will notice the rate of time for the rest of the universe is speeding up.
People outside will notice no difference in their time. But, looking in the window of your spaceship, they will notice your time is slowing down. You are moving in slow motion.
This has been confirmed by hard experiments.

Time and space are the same thing. Time and space are mutual.

Once your spaceship hits exactly the speed of light, people outside will see that you have completely stopped.
You, going at exactly the speed of light notice nothing unusual for yourself. However, when you look out your window you will see the universe has disappeared !

Without time there is no space, without space there is no time.

How does the universe exist for a photon ?

Going faster than light doesn't mean you will reverse time and go back into the past.
Once you reach the speed of light, the universe disappears and there is no past to go to.
 MikeWM
Joined: 2/7/2011
Msg: 56
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Posted: 11/1/2011 11:10:32 AM
Actually nobody knows what will happen if you travel faster than the speed of light, its still classed as a theoretical speed limit

And we only assume you cant travel backwards in time, its another thing we dont actually know. other things we used to think we knew were than if you drove in a car the speed would kill you, that flight was impossible and that travelling faster than the speed of sound would turn your internal organs to mush

Infact if I remember correctly space wouldn t dissapear at the speed of light, I'm fairly sure you would see things that were behind you whilst looking forwards actually

The idea that theres no time without space doesnt really seem relevant and just looks like a random statement thrown in to up the word count though,

But what youre actually referring to with the universe "dissapearing" isnt that it somehow magically ceases to exist or gets sucked through a wardrobe star into the galaxy of narnia, its to do with you travelling at the same speed as the photons themselves and not actually being able to visually see them rather than them ceasing to exist, So yes there would be a universe to "go back" to, it hadnt actually gone anywhere in the first place.

That was a bit like saying "If I close my eyes the universe doesnt exist anymore" which obviously it does otherwise blinking would be apocalyptic
 MikeWM
Joined: 2/7/2011
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Posted: 11/2/2011 4:48:31 PM
I did actually spend a bit of time pondering the problems with the "portal" not being in he past before I did an earlier post and was sort of leaning towards the creation of the time portal being the earliest any time traveller could travel back to

But as such a device would in effect be creating a tunnel, unless the tunnel could "only" be created from one portal to another in a similar way to the experiments to create subspace tunnels with huge electromagnets it could still be possible

But it might mean as is the case in the new TV series Teranova that a single ended manipulation of space/time could only be used one way, so you would have to also take an IKEA portal with you if you wanted to return a bit like shooting someone from a catapult, or skydiving

Or that the distortion once open could be traversible in both directions like a fire escape allows, in that even though the opening mechanism is only on one side, once opened bidirectional travel would then be allowed
 CountIbli
Joined: 6/1/2005
Msg: 58
Time Travel-Is it possible?
Posted: 11/2/2011 7:51:32 PM
"And I guess rather than possibly clouding the statement by using the term "tachyon" something like antiphoton might be better."

Actually photons are their own anti-particle.

Charged tachyons are pretty interesting. When accelerated they emit radiation (like any other charged particle) and therefore lose energy. But for a tachyon losing energy means that it speeds up! So when it speeds up it loses even more energy to radiation and speeds up some more. And so on.
 hvclmail
Joined: 12/14/2006
Msg: 59
Time Travel-Is it possible?
Posted: 11/2/2011 9:40:05 PM
If the astronaut were in a close enough orbit around a black hole and could eventually escape to a normal gravity field (probably requiring a huge amount of energy), he would not age relative to the rest of the cosmos and may be able to witness the "end of the universe". This effect of gravity on him is the same as he would have if he were travelling very close to the speed of light. From his point of view, he has traveled into the future.
 nipoleon
Joined: 12/27/2005
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Posted: 11/3/2011 12:07:29 PM
We cannot see the future and we cannot see the present.
We can only see the past. Everything we see is only what used to be, not what is right now.

Go outside and look up into the sky..... do you see the Sun ?
That which you see is not the Sun as it is right now in the present. It takes 7.5 minutes for light to travel from the Sun to the Earth. So... what you see in the sky is only the " apparent " position of the Sun. The real position of the Sun is actually 7.5 minutes further to the West and is completely invisible to us here.

When you look at your image in a mirror, you are only looking at yourself as you were in the past.
Sure.... it's a billionth of a second in the past but it's still in the past.
We cannot see the present, this instant. We can only see what was.
Everything we see is what was, never what is right now.

Space and time are the same thing. Moving through space changes the perception of space and time. The faster you accelerate through space the more your perception of time and space changes. When you reach the speed of light, time doesn't exist anymore and space doesn't exist anymore.... for you.
For you, the universe disappears.

Our whole experience of the cosmos is entirely dependant upon our particular position.
 MikeWM
Joined: 2/7/2011
Msg: 61
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Posted: 11/3/2011 1:01:16 PM

Here's the idea, suppose you had a time machine that you had never used, you were the inventor of it, and on a certain day you used it and sailed off into time, the future.
Well then the presumption would be, since your the inventor of the first time machine, that just moments after that event , time machines from all points in the future would converge on your departure point


I do get the point to point theory and its limitations

But heres another analogy

If youre theorising actual time travel rather than just time dilation is possible then obviously carrying on with the portal or stargate type mechanism idea youre static (other than standard planetary movements at the time)

So it would seem logicaly that youre actually travelling by virtue of some type of manipulation of particles of some sort not currently known, or exciting ones that are known in a weird and wonderfull manner to create the connection between two points in time and space

Infact take that idea forward and if it was a necessity each portal might also need to be configured to connect to the other, so it would then only be possible by prior concensus anyway making multiple unexpected guests also an impossibility when the first one was invented

But leaving that aside for a moment and going back to the particle or wave manipulation angle.

Think of a small lagoon or lake, it would be quite possible to create a machine that created such a powerful circular torrent that you could create an inverse whirlwind type effect till you could see the bottom of the lagoon. Jump into it and stand water unimpaired on the exposed floor

(Dislaimer, there might be one or more physical reasons this wouldnt actually work lol, but its the best easy to visualise analogy I could think of (I'm blond, its genetic and therefore not my fault ))

So you only had a "portal" at one end of the whirlpool, but could still create the "tunnel" through the matter in question

If that type of manipulation was what was actually needed then single ended travel in one or even both directions could be possible

but even if you could only go one way, the option of also taking a flatpack ikea version of the portal with a wheelbarrow full of duracells with you for a return trip would be a workaround for the return trip
 nipoleon
Joined: 12/27/2005
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Posted: 11/4/2011 2:55:53 AM

So if its confirmed that the neutrino's went faster than light speed were they outside of time and space ?

That is a very pertinent question.

What reality does a photon experience ? Traveling at the speed of light, the universe we experience doesn't exist anymore. Does the universe of planets, stars, and galaxies make the real universe ? Or is it something else ?
Which reality is real ?

We are stuck, like a fly on flypaper upon a continuum of energy. Our whole universe is a spectrum of energy which is difficult to move around in.

However.... time, space, and gravity are all the same thing.
If you can manipulate one of those three, you can manipulate the other two.
 MikeWM
Joined: 2/7/2011
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Posted: 11/4/2011 4:40:54 AM
I have always wondered whether the three were actually time space and gravity tbh

If the perception of gravity was back to front, and rather than emanating from a mass was actually the action of particles being attracted to it then the actual triad would infact be time, distance and gravity, space itself wouldnt alter, but the tidal influences on the flow of gravity particles (gravitons?) would flow more intensely towards a creater mass and change the passing of light through normal space (imagine someone swimming in a swimming pool) to light passing through a strong gravity torrent (thing of the same swimmer trying to swim across the egde of waterfall)

Space itself wouldnt have altered, but the conditions within the space have
 Kohmelo
Joined: 9/20/2011
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Posted: 11/9/2011 5:42:26 PM
Based on this link, assuming all theoretical assumptions to be true, if one were to open a worm hole between earth and a black hole, would not the gravitational pull of the black hole be conducted through the worm hole thus pulling on the earth like a vacuum cleaner would pull on a tennis ball and seriously have a negative effect on our orbit?
 MikeWM
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Posted: 11/10/2011 4:30:44 AM
A black hole (as I understand it) isnt strictly speaking a "hole" it has an extremely dense chunk of matter at the centre of it that you would kind of splat into like a bug on a windscreen

A "worm hole" however is a tunnel between two points, so although you might get squished the splatability index should be pretty non existent, although ejecting from the other end as a jet of molecules would probably still count as severely bad hair day by all accounts
 Kohmelo
Joined: 9/20/2011
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Posted: 11/10/2011 2:07:22 PM
I'm not sure if you answered my question. I'm not sure if I posed it clearly
The proposal in the video offered up 3 posts ago was to create a worm hole with one end at the earth and the other end at a black hole.
Now I know the person that was dumb enough to head over to the black hole is going to get squished something fierce, but my question was if the force of gravity of the black hole would be conducted by the worm hole? Would the gravitational pull of the black hole effect the objects on the earth that have not entered the worm hole?
 MikeWM
Joined: 2/7/2011
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Posted: 11/10/2011 3:58:45 PM
Sorry, youre totally right I missunderstood what you had said


I guess that would depend on how "gravity" actually works really, which is something else that is really based on a house of cards of various theories stacked one on top of the other rather than actual facts based on definitive knowledge compared to assumptions based on observations

I would be "more" inclined to think that a black hole would be able to create/present the same forces at the distant end of a worm hole but that would really be no more than a 60/40 type of split really

If gravity is something exerted by a mass, and the worm hole creates the semblance of a short distance between two points then that would seem to be a "reasonable" assumption

If on the otherhand a large mass simply provides something akin to a vaccum that gravity particles have a natural predisposition to flow into then it would depend on where gravity particles exist in the highest numbers and whether the interaction between the two pressures could interact through a worm hole to begin with

thats probably not clear, but the best analogy I can thing of is this

Imagine that a large mass was in effect a plug hole, and gravity particles were water. You could phone somebody (your wormbole) and send sound information back and forth, but the plug hole at their end wouldnt attract water that you then poured over your handset through the wormhole

There would need to be some kind of compatibility between the medium and the item to be attracted or transferred
 Dave_eh
Joined: 10/29/2011
Msg: 68
Time Travel-Is it possible?
Posted: 11/11/2011 7:48:29 AM
If it was, I doubt we'd ever know it.

I think that if a person travelled backwards in time, instead of changing anything in the timeline they were born in, they would simply start a new timeline.
 abelian
Joined: 1/12/2008
Msg: 69
Time Travel-Is it possible?
Posted: 11/11/2011 7:56:45 AM
I'm not sure if you answered my question. I'm not sure if I posed it clearly
The proposal in the video offered up 3 posts ago was to create a worm hole with one end at the earth and the other end at a black hole.

The answer to your question is not simple, except for the special case where you are talking about the maximal extension of the Schwarzchild spacetime (a Schwarzchild black hole) where you have an Einsten-Rosen bridge as the wormhole. In that case, the answer is that you can't make such a wormhole stable, so it isn't traversable.

Now I know the person that was dumb enough to head over to the black hole is going to get squished something fierce, but my question was if the force of gravity of the black hole would be conducted by the worm hole? Would the gravitational pull of the black hole effect the objects on the earth that have not entered the worm hole?

Since gravity is the reason such a womhole exists, that isn't the right question to ask. The right question is ``Can you create a wormhole with a gravitational field that would allow it to be traversable.'' The answer is maybe, but probably not. The only way known to obtain such a gravitational field is with some sort of ``exotic matter'' that violates one or more constraints on the field equations, which seem to hold for all gravitational phnomena observed so far. Since the ``exotic matter'' was invented precisely to investigate what type of matter would be required to produce such a wormhole and matter with those properties has never been observed and would actually be quite weird, I don't think anyone would bet that it exists. I mean, it's possible to take a set of equations and get almost any answer you want if you're creative enough, but once you get the answer you want, you have to ask if the conditions required to get that answer, make physical sense.

There are lots of (scientific) articles about this subject you can obtain by going to scholar.google.com and searching for ``wormhole'' and ``metric.'' Even if the details are rather mathematical, you should be able to find text that summarizes the results.
 abelian
Joined: 1/12/2008
Msg: 70
Time Travel-Is it possible?
Posted: 11/11/2011 2:39:37 PM

I guess that would depend on how "gravity" actually works really, which is something else that is really based on a house of cards of various theories stacked one on top of the other rather than actual facts based on definitive knowledge compared to assumptions based on observations

Say WHAT? Do you really have any idea of how few assumptions are required to derive general relativity and the extent to which it's been tested through experients and observations? I mean, the assumptions required are so few as to be almost ridiculous. All you need to assume is that gravitational mass and inertial mass are equivalent. To avoid general relativity as a theory of gravity, you actually have to assume more than than general relativity assumes. I really can't think of a theory which is more elegant and natural than general relativity.
 Tah,
Joined: 11/18/2008
Msg: 71
Time Travel-Is it possible?
Posted: 11/12/2011 5:07:07 AM
The way my undereducated and naive mind works understands it that if we are able to make it to another star system we would of travelled forward in time .
 MikeWM
Joined: 2/7/2011
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Posted: 11/12/2011 11:12:04 AM

I mean, the assumptions required are so few as to be almost ridiculous


Which was the point of my comment

If you "have" to assume something then it is a house of cards built on assumptions, not actual "knowledge"

And until we can actually detect or definitively quantify and observe exactly what causes the effects of gravity thats what it will remain

Pretty much all "observations" pertaining to gravity would work just as well whether it was a force exuded by an object or a flow of particles TO an object proportionate to its size

Infact to some extent the behaviour of light near the event horizon of a black hole would be better explained with the later and would make sense without also then having to assume "space and/or time" needs to be bent or distorted as the behaviour of light could be explained without either of those two things being necessary
 _TALL_IQ2_
Joined: 2/10/2010
Msg: 73
Time Travel-Is it possible?
Posted: 11/12/2011 11:36:28 AM

If you could go forward

Actually most all of us ARE right now going forward in time, and in space.. Maybe not at the RATE you may have been imagining..
There are just a few Forumites who seemingly can go "backwards"..

It is now 1 month since you posted this thread, and you have traveled that month along with most of the rest of us..

When we find the Higgs boson, or can produce enough anti-matter to matter, we may learn to produce stable micro black holes..

IF we throw a mouse in to see if the "mouse" data survives somewhere long enough to recreate that same mouse elsewhere.. Then we may learn to time travel..
 Kohmelo
Joined: 9/20/2011
Msg: 74
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Posted: 11/12/2011 1:31:58 PM
Isn't the term micro-black hole an oxymoron?
 MikeWM
Joined: 2/7/2011
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Posted: 11/12/2011 5:00:24 PM
Maybe those ones were discovered by the japanese, they seem to have a knack for making everything smaller

Dunno what it actually is tbh (and too tired to google it) but oxymoron?

Surely the size of the matter at the heart of a black hole can vary in size, so the level of influence would vary accordingly, so having some so tiny theyre classed as a "micro black hole" doesnt seem that silly really

If anything its the fact its got "hole" in the title that I've always found a bit daft
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