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Time travel (209)

1 Name: Anonymous Scientist : 2006-07-20 11:12 ID:6bO6LaVD

Do you think it's possible?

2 Name: Anonymous Scientist : 2006-07-20 21:00 ID:V6IBoqJE

If you have a Delorean

3 Name: Anonymous Scientist : 2006-07-20 21:38 ID:2/lMP+G6

and some plutonium

4 Name: Anonymous Scientist : 2006-07-21 07:59 ID:5DB94XDu

Yeah and then you just need to accelerate to 88 MPH :D
Ok, I love that movie, in fact Back to the Future is one of my favories.
But my question is somewhat serious.
Imho time travel maybe possible but only for traveling to the past. I think future isn't determined yet so you cannot go there. On the other hand, going to the past and changing only a minor thing can lead to huge effects on the present. Just is you go to the past, you've already changed it.

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5 Name: Anonymous Scientist : 2006-07-21 08:31 ID:SnW+PwLL

I watched a whole show on this on either Discovery, Learning Channel, or oddly enough, History Channel. Maybe I watched it on Nova back when I was still watching Nova.

Anyway, they talked about Einsteinian physics and said that as far as we understand the universe time travel is inherently possible. Science has accepted that. But, what does that mean? Is it possible to go back in time to kill your grandfather before your father is born? That's the paradox question that comes up every time you get into time travel.

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6 Name: Anonymous Scientist : 2006-07-21 14:23 ID:LY1xpFZJ

Once we invent the Flux Capacitor...

7 Name: Anonymous Scientist : 2006-07-21 17:43 ID:2/lMP+G6

>>6 Nah, the flux capacitor is most likely a simple wave generator.
I'm more worried about the 1.21 gigawatts of power needed...
We don't have portable plutonium-powered nuclear reactors currently.

8 Name: The Prof : 2006-07-21 17:46 ID:wjII0OVr

But we have Mr. Fusion :D

9 Name: Anonymous Scientist : 2006-07-22 12:41 ID:2/lMP+G6

>>8 But Mr. Fusion is in the future... TIME PARADOX!

10 Name: Anonymous Scientist : 2006-07-22 22:42 ID:VzUJnlrH

Back to the topic (oh dear god no!! I didn't mean to)

I don't believe so. I'm too tired to explain it, but I thought about it enough to right a 3 copy page essay on it last year.

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11 Name: Anonymous Scientist : 2006-07-23 15:28 ID:yeOQlzIA

At least thirty years back, there were some papers published discussing the possiblity. I mean scholarly papers, from physicists, who were looking at the mathematical models in Einstein's theory of relativity and examining them under unnatural, possibly impossible conditions.

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12 Name: Anonymous Scientist : 2006-07-24 00:26 ID:2/lMP+G6

>>10 Time travel is a reality. I'm travelling in time right now. And so do you. At 1x speed.

13 Name: Anonymous Scientist : 2006-07-24 12:05 ID:ZFmfiOfB


Your humble opinion is completely wrong. Time travel into the future is very easy. Besides the fact that you're travelling there right now, simple special relativity tells you that if you're in a hurry, you just need to go move very fast and you'll get there quicker. Once you're there, though, you're stuck.

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14 Name: Anonymous Scientist : 2006-07-27 04:49 ID:Esy8Gj2L

Using what I've heard and read of time travel and parallel universes, most likely what would be experienced in time travel is just going to a universe that is however far back as you think you've traveled (say 2006 to 1920s, just 86 years behind ours). Because of this, coming back here will show no know changes because it affected another world entirely.

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15 Name: Anonymous Scientist : 2006-07-27 14:16 ID:2/lMP+G6

>>13 Yeah. There is also gravitational time dilation: for example the GPS satellites we have in orbit have their clocks running behind. I guess one could say that the satellites are time-travelling into the past, by a minute amount.

16 Name: Haiiro : 2006-07-29 03:22 ID:sRCevtic

GPS satellites, as they are orbiting or just falling through the vaccum of space, aren't affected (or very little) of gravity. Somehow matter moves at a slower pace when not under gravity. So clocks on satellites tend to stay behind earth-time and need to become updated in a periodic basis.

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17 Name: Anonymous Scientist : 2006-07-29 20:01 ID:Heaven

I think biological clocks have as much to do with time travel as sunglasses with have with nuclear fusion.

18 Name: Anonymous Scientist : 2006-07-31 19:48 ID:bbWgBel6

>>17 Lol. Good analogy.

Yes, time travel is possible under Einsteinian physics. Unfortunately we have no clue how it works nor how to move backwards through time. Since to move backwards in time forces us to break the speed of light, which also under Einsteinian physics is impossible. Tests have shown however that time travel is possible. We have tested and measured small instances of slowing time, most notably through the use of atomic clocks placed in orbit.

19 Name: Anonymous Scientist : 2006-08-03 18:26 ID:JXZ4g7yq


You are technically correct that we have "tested and measured small instances of slowing time", but this really is a bit misleading. Not only are experiments confirming this (by necessity) done every day, but many everyday occurances depend on it - notably, GPS navigation.

20 Name: Anonymous Scientist : 2006-08-04 03:00 ID:2/lMP+G6

Adding to my comment >>15, "time travel into the past", I'm still not sure of my assertion. Is it the GPS clock that moves backward in time, or is it the clock on the ground that moves (fast)forward in time?

21 Name: Anonymous Scientist : 2006-08-05 01:16 ID:SnW+PwLL

I think you're misunderstanding. Both are moving in time at the same speed according to the effects of both gravity and motion. Since according to Einsteinian physics the closer you are to a gravitational center the slower you move in time. Also the faster you travel the slower you move in time.

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22 Name: Anonymous Scientist : 2006-08-05 02:30 ID:GICCrd1N

People... "time" doesnt exist...
its invented by humans to make life a little easier, like: "hey lets meet at 7 ok?"
the so called "ageing" is just a procces off cells breaking down
so how can time traveling be possible is there isnt even time to travel with?

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23 Name: Anonymous Scientist : 2006-08-05 04:15 ID:2/lMP+G6

>>21 Okay, but which time should a time traveller sync his clock to? I suppose that with the Moon orbiting Earth, they are variations in the atomic clocks on the ground as well. Also planets/the Sun moving closer or away. Don't those ground clocks get out of sync with each other at times? Or not?

24 Name: Anonymous Scientist : 2006-08-06 19:37 ID:SnW+PwLL

Yes, a clock set on the moon will move at a different rate then one on Earth, or the Sun, or Jupiter, or wherever it's placed. It's unavoidable. We do the best we can with what we've got though and right now since Greenich standard time is universal on Earth you can assume that it's universal in the Galaxy (assuming of course that we're all there is in intelligent life). Any clock which gets out of sync presumably would be reset to GMT whenever possible.

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25 Name: Anonymous Scientist : 2006-08-08 13:28 ID:JXZ4g7yq


The basic principle of relativity is that there is no preferred reference frame. That is to say, there is no clock to sync to. All clocks run different, and there's nothing you can do about it, except choose an arbitary one to call your standard time. Even if you do, it won't have anything to do with any deeper aspect of reality, it will just be bookkeeping for yourself.

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26 Name: Anonymous Scientist : 2006-08-08 16:15 ID:2/lMP+G6

There is another way of timetravelling into the future that hasn't been mentioned above yet, and that's temperature.
For example, food in the fridge decays slower that in the heat.
So this is yet another factor that could influence an atomic clock, isn't it?

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27 Name: Anonymous Scientist : 2006-08-08 18:32 ID:zJqXzlir

> But! The effects of being away from the center of the earth is negligable compared to the effects of traveling at high speed that slows it down.

But! all movement is relative, so it isn't actually moving at all.

28 Name: Anonymous Scientist : 2006-08-08 21:01 ID:bbWgBel6


Cold only slows down the atoms. I don't believe cold has anything to do with slowing time to any degree. It's used to preserve foods because it keeps bacteria and molds inactive.

29 Name: Anonymous Scientist : 2006-08-08 22:49 ID:Heaven


No. Lay off the acid.

30 Name: Anonymous Scientist : 2006-08-09 15:10 ID:2/lMP+G6

>>28 Wait, wait... if cold is slowing down the atoms, why has it no influence on an atomic clock?

31 Name: Anonymous Scientist : 2006-08-09 15:50 ID:Heaven

No. Lay off the acid.

32 Name: Anonymous Scientist : 2006-08-09 16:53 ID:Heaven


Just because both the statements "slowing down the atoms" and "atomic clock" have the word "atom" in them, does not mean they are directly related.

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33 Name: Anonymous Scientist : 2006-08-10 13:29 ID:2/lMP+G6

>>32 Well, okay. I need to look up how an atomic clock works.

Rephrasing my other question: are forward-timetravel factors (gravity + speed) cumulative?

34 Name: Anonymous Scientist : 2006-08-10 15:29 ID:Heaven

gravity and speed are the same factor.

35 Name: Anonymous Scientist : 2006-08-10 18:52 ID:bbWgBel6

Yes, they are cumulative.

36 Name: Anonymous Scientist : 2006-08-10 20:09 ID:JXZ4g7yq

Well, it's not as simple as being "cumulative". >>34 has it, they're different sides of the same thing. The important thing is paths through space-time. Figuring out what the result will be with strong gravity and high speed is nowhere near intuitive. You pretty much have to work through the maths to figure it out.

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37 Name: Anonymous Scientist : 2006-08-11 14:55 ID:2/lMP+G6

I see. Ok, my next question:

As one's velocity increases, one goes forward in time. The maximum speed is the speed of light, and is a known constant.

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38 Name: Anonymous Scientist : 2006-08-11 21:31 ID:Heaven

black hole?

39 Name: Anonymous Scientist : 2006-08-12 06:53 ID:WiTTMhOC

We are always Time Traveling to the future!!

40 Name: Anonymous Scientist : 2006-08-12 14:38 ID:JXZ4g7yq


There is no maximum as such for how strong a gravity field can be. However, a strong enough gravity field can reach the point where spacetime is bent to the point that no particles can escape, even if they move at the speed of light. As a first approximation, you can think of it as a gravity field so strong that the escape velocity is higher than the speed of light (however, you will need to account for relativistic effects when considering this in practice).

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41 Name: Anonymous Scientist : 2006-08-12 17:04 ID:2/lMP+G6

>>40 Something I don't understand here. Light cannot escape a black hole (obviously), but light particles have no mass, which is why they can travel at the speed of light. If a particle has no mass, how come it can be trapped in a gravity well?

42 Name: Anonymous Scientist : 2006-08-12 23:05 ID:Heaven


Because the simplistic view of gravity as masses acting on masses in the Newtonian model is incorrect.

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43 Name: Anonymous Scientist : 2006-08-13 15:02 ID:2/lMP+G6

>>42 Is the warping of spacetime temporary?
That is, does a light ray after passing near a strong gravity like a sun (looking bended while doing so), re-take its original trajectory?
In other words, is it just an optical illusion?

44 Name: Anonymous Scientist : 2006-08-14 19:30 ID:bbWgBel6

Simply put, no.

Optical illusions are created either by the brain misinterpreting information or light passing through a medium like water or air which distorts the image. Neither is happening here.

45 Name: Anonymous Scientist : 2006-08-15 12:49 ID:E4evLiqi


The Sun's gravity field is actually not all that strong, but it is the strongest we have nearby. And no, it's not temporary - spacetime is warped by the presence of mass. Light moves along straight lines in spacetime. After passing close to a large mass, the direction of the light will have changed.

46 Name: Anonymous Scientist : 2006-08-15 15:20 ID:2/lMP+G6

Ok, I think I get it.
So, near a strong gravity field spacetime is warped, and that includes whatever light ray that passes thru it. Also, time is passing faster.
What if the strong gravity field is inverted? In a mathematical model of an inverted gravity field, is the time factor also inverted?

47 Name: Anonymous Scientist : 2006-08-16 13:54 ID:E4evLiqi


Time passing faster is not a separate effect. Also, time can pass slower or faster, depending.

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48 Name: Anonymous Scientist : 2006-08-16 15:25 ID:2/lMP+G6


Has there been any known instance of black holes vanishing?
Or black holes appearing where there were none before?

49 Name: Anonymous Scientist : 2006-08-16 19:59 ID:bbWgBel6

blech, you're starting to ask questions that are beyond me. Basically I can answer that stellar phenomenon like the creation of black holes, is not something that occurs in any amount of time we as humans can witness. It basically takes eons to mash stars together or cause them to explode thus creating black holes. I remember reading a short paper by Stephen Hawking that explained that there's a subatomic particle which is created spontaneously in space. If one were to be created on the edge of a black hole (the event horizon) part would spiral back into the black hole while half would break away and return to normal space. This is the only way a black hole can reduce it's mass, eventually decaying over countless millenia. It's been years since I read that article so the science behind it is beyond me now.

50 Name: Anonymous Scientist : 2006-08-16 23:43 ID:Heaven


We still can't observe black holes directly, only their large-scale effects, and even those can be hard to unambiguously make out. As far as I know we don't have perfectly solid evidence they exist yet (although lots of circumstantial evidence, so to speak).

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51 Name: Anonymous Scientist : 2006-08-17 14:11 ID:2/lMP+G6

OK. It seems we'll have to wait for the CERN's LH Collider in 2007 to (hopefully) crank out mini black holes to study before we can map fully the black hole's properties.

52 Name: Anonymous Scientist : 2006-08-20 00:53 ID:SGb3zWWj

Before you can ask yourself "is time travel possible?", you first must ask yourslef "what is the nature of time?". We don't know for sure that time really physically exists at all, it may just be a concept that we associate with the changes in the world around us, and use to chart the progress of those changes, a concept we have become so dependant on that we view it as something physical that can be seen or changed or altered. The fact is we don't know for sure that time is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.

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53 Name: Anonymous Scientist : 2006-08-20 01:40 ID:Heaven

Before you can ask yourself "is space travel possible?", you first must ask yourslef "what is the nature of space?". We don't know for sure that space really physically exists at all, it may just be a concept that we associate with the changes in the world around us, and use to chart the progress of those changes, a concept we have become so dependant on that we view it as something physical that can be seen or changed or altered. The fact is we don't know for sure that space is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.

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54 Name: Anonymous Scientist : 2006-08-21 19:34 ID:bbWgBel6

>>53 Um, we're not talking about the philosophy of existence but the observable nature of spacetime. So, please don't bring psychology into a discussion of physics. You may be correct, we could all be brains placed in a jar and fed stimulation to see our reactions but since we can't measure that scientifically we discuss the things we can measure. And by our mathematics and knowledge of physics time travel IS possible.

55 Name: Anonymous Scientist : 2006-08-23 12:21 ID:E4evLiqi

> The fact is we don't know for sure that time is a physical thing at all, it may just be all in our heads, a psychological crutch, if you will.

Spoken like a true philosopher with no knowledge whatsoever about the actual physics of what he is talking about. When you say "we", you really mean "I", don't you?

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56 Name: z : 2006-11-20 11:37 ID:mXCNc57F

To understand timetravel one must first understand time and if this 'time' really exists.

Is traveling faster than the light timetravel? We are looking up at the stars and looking back in "time" beacuse the light is extremely slow when it comes to interstellar distances.

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57 Name: Anonymous Scientist : 2006-11-20 19:06 ID:JXZ4g7yq

> Is traveling faster than the light timetravel?

No, because there is no such thing as "traveling faster than light".

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58 Name: Anonymous Scientist : 2006-11-20 19:08 ID:2/lMP+G6

To understand spacetravel one must first understand space and if this 'space' really exists.

(...wait, I already did this joke earlier in this thread.)

59 Name: Anonymous Scientist : 2006-11-21 09:16 ID:mXCNc57F

>No, because there is no such thing as "traveling faster than light".

I know we aren't able to travel faster than light.. YET!

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60 Name: Anonymous Scientist : 2006-11-21 09:18 ID:Heaven

and i mean 'faster than the speed of light'.. not light itself -__-;

61 Name: Anonymous Scientist : 2006-11-21 13:26 ID:Heaven

>How is it possible for me to look at women yet not be able to become one?

Becoming something is not the same as traveling to something.

62 Name: Anonymous Scientist : 2006-11-21 23:51 ID:JXZ4g7yq

> Why can you travel @ the speed of light (light does this) but not actually go 1m/s faster than it?

Because "1m/s faster than light" is a meaningless concept. You only think it makes sense because you are used to very low velocities. Your intuitive image of the universe is nowhere near correct, and it is that incorrect image which makes you think moving faster than light makes sense.

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63 Name: Anonymous Scientist : 2006-11-21 23:53 ID:JXZ4g7yq

> Becoming something is not the same as traveling to something.

Similarly, seeing something is not the same as travelling to it.

64 Name: Anonymous Scientist : 2006-11-22 09:20 ID:Heaven

>the maximum possible speed. The structure of the universe is such that moving faster than light is not something that can happen.

yeah, and there cant be life without water... lolz

65 Name: Anonymous Scientist : 2006-11-22 13:03 ID:E4evLiqi


I am telling you the truth, but you refuse to listen, so what can I do? Well, I guess I can tell you what happens if you try to go faster than light. Please try and read and understand at least some of this.

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66 Name: Anonymous Scientist : 2006-11-27 04:05 ID:vgIuB127

ok suppose that we have a looooooooooong tube with inside diameter of 1 cm and length of 10 light seconds. and in side this tube is full of small 0.9 cm metallic spheres lined up from one end to the other. so you push the first sphere. with common sense, you might think that on the other end of our tube, a sphere drops instantaneously right? I mean, nothing is moving faster that the speed of light right? you are just pushing one sphere slowly and on the other end, no matter how long the tube is, one should come out of the tube.

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67 Name: Anonymous Scientist : 2006-11-27 09:32 ID:mXCNc57F

scientists are known to have slowed the speed of light down, and there was an incident in a russian nuclear reactor, i cant remember what it was, but there was some matter that travelet faster than the speed of light.

google for it, it's there..

68 Name: Anonymous Scientist : 2006-11-27 17:28 ID:JXZ4g7yq


Light travels at less than "the speed of light" in a medium. When people say "the speed of light", they actually mean "the speed of light in a vacuum", also known as c. Travelling faster than the speed of light in a medium is not only possible, it happens all the time around nuclear reactors. It causes a phenomenom known as Cherenkov radiation, which incidentially is quite pretty:

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69 Name: Anonymous Scientist : 2006-11-29 12:12 ID:Heaven

im not talking about light itself.. just the speed it has.

70 Name: Anonymous Scientist : 2006-12-09 02:09 ID:vnkaDxrv

Didn't Kurt Godel have something important to say about time travel in relative space.

71 Name: Anonymous Scientist : 2006-12-10 18:10 ID:Heaven

Gödel was a mathematician, not a physicist.

72 Name: Anonymous Scientist : 2007-01-30 21:51 ID:QPZM8lgA

From Wikipedia's article on "Kurt Godel."

"In the late 1940s, Gödel demonstrated the existence of paradoxical solutions to Albert Einstein's field equations in general relativity. These 'rotating universes' would allow time travel and caused Einstein to have doubts about his own theory."

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73 Name: Anonymous Scientist : 2007-01-31 12:31 ID:Heaven


Well, you learn something new every day!

74 Name: Anonymous Scientist : 2007-02-01 22:59 ID:OodQrro+


almost. it does happen pretty much simultaneously with the first ball. it will simply take 10 seconds to observe the ball fall out of place, because of the distance the light has to travel to reach back to you. an observer at the other end will see the ball fall out of the tube before you push it, in theory. thats also assuming you can even move that many small metal bearings. they should weigh in the vicinity of several tonnes.

75 Name: Anonymous Scientist : 2007-02-02 01:45 ID:JXZ4g7yq


That's plain and simply wrong. It will take at least 10 seconds, in practice much, much longer, before the last ball starts to move. The reason it takes longer is that the pressure will move through the system at the speed of sound, not the speed of light. The speed of sound in a metal is pretty high, but it's much less than the speed of light.

76 Name: Anonymous Scientist : 2007-02-02 08:23 ID:pCdOblrF

so the energy you apply to item #1 moves to item #2 and so on. but, assuming we has something strong enough to push them all, wouldnt that mean that either 1) the metallic bearings would change shape, or even break under the pressure or 2) two bearings will occupy the same space at the same time. assuming the bearings are indestructable, neither scenario seems likely. but im also imagining a constant application of pressure, not a impact, like you see on those desk-ornaments with the balls on string.

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77 Name: Anonymous Scientist : 2007-02-04 15:35 ID:JXZ4g7yq

> wouldnt that mean that either 1) the metallic bearings would change shape, or even break under the pressure


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78 Name: Anonymous Scientist : 2007-06-24 22:55 ID:Zv2mBs0a

>>59 The only way to travel faster than the speed of light is by cheating. Usually this involves parallel dimensions or creating a "warp bubble" around you spaceship.
The reason you can't travel faster than light is, basically, because you can't.

79 Name: Anonymous Scientist : 2007-06-25 19:55 ID:X4CV/S9s

It's possible. Very likely too if you consider the following "time travel"

You could build spaceship that accelerates at 1g. It would take you 24 years to get to Andromeda galaxy in your time frame, remember you would be going at relativistic speeds (time dilation). But us here on earth, we would see you on your way for millions of years.

80 Name: Anonymous Scientist : 2007-07-21 07:09 ID:FeesWdyy

There. I guess it's not just normal people who believe this shit. The project funders must have too much money in their hands.

81 Name: Anonymous Scientist : 2007-07-30 14:53 ID:TxHhdkbQ

>>39 ya , lol

82 Name: Anonymous Scientist : 2007-07-31 04:42 ID:Qix6jNpG

If time travel to the past was possible, we'd currently be flooded by otakus from the future who want to catch original broadcasts of Lucky Star.

83 Name: Anonymous Scientist : 2007-07-31 12:21 ID:sW+pmhcT

>>82 The RIAA from the future will not allow it for copyright reasons.

84 Name: Anonymous Scientist : 2007-10-12 05:19 ID:T9RzPwMp

Believe Einstein. I think you can go into the future if you can travel at the speed of light. I think it's true that it is relative to the space you are in so as you travel at the speed of light it might not seem like you have aged but you return and everyone else will be older depending on how long you were away. Maybe it is not time travel but age travel.

85 Name: Anonymous Scientist : 2007-10-12 13:07 ID:sW+pmhcT


86 Name: Anonymous Scientist : 2007-10-12 16:20 ID:Heaven

I'm going into the future right now!

87 Name: Anonymous Scientist : 2007-10-13 00:13 ID:Heaven

reverse the polarity.

88 Name: Anonymous Scientist : 2007-10-13 12:10 ID:sW+pmhcT

Great Scott! Where are you going to find 1.21 gigawatts??

89 Name: Anonymous Scientist : 2007-10-13 15:03 ID:+Swof75c

all time is occurring simultaneously. It's like pictures in a flip-book. All other informationis classified.

90 Name: Anonymous Scientist : 2007-10-15 07:48 ID:J+ol/sfP

no its not possible, period.

91 Name: John Titor : 2007-10-15 23:40 ID:Heaven

It's real, and I can prove it!

I just don't feel like it...

92 Name: Anonymous Scientist : 2007-10-18 02:19 ID:kbhYcDY3


93 Name: Anonymous Scientist : 2007-10-18 02:20 ID:kbhYcDY3

I can travel back in time to >>92

94 Name: Anonymous Scientist : 2007-10-19 07:22 ID:idwUBqtg

Nobody managed to go backward, and so far it seems impossible,...

95 Name: Anonymous Scientist : 2007-10-19 11:41 ID:Heaven


What, >>93 totally did it!

96 Name: Anonymous Scientist : 2007-10-19 13:24 ID:sW+pmhcT

I can go backward any time, the problem is how to bring my body with me.

97 Name: Marty McFly : 2007-10-21 21:49 ID:6cEGOR5r

I managed to do it at least to years ending in "5", and then I had to go and wreck the delorean... At least now I have something that travels between years ending in "7", so welcome summer of love!

98 Name: Anonymous Scientist : 2007-10-21 22:01 ID:6cEGOR5r

Stephen Hawking once tried to prove time travel was impossible by means of a convoluted argument that took into account several factors, and then tried to argue that all of them didn't work, probably in an effort to explain why he considered such things as the "grandfather paradox" to be impossible. Seems to run afoul of Occam's Razor to me (but I wish I remembered the argument). There is another school of thought: that if people were to travel back in time and change history, they'd wind up in an alternative universe or in another timeline (and THAT has spawned an entire science fiction subgenre itself).

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99 Name: Anonymous Scientist : 2007-10-21 23:01 ID:sW+pmhcT

>>98 There is a third option. In some of the Philadelphia Experiments (Scifi or truth? We may never know.) they sent some accomplice back in time to kill the father of some guy, but when the killer came back there was no change in the present. The only thing that changed was that the memory of the father of the guy was somehow fading away.

100 Name: Anonymous Scientist : 2007-10-22 19:19 ID:wvcUGj1x

100 Get

101 Name: Anonymous Layman : 2007-10-22 23:00 ID:VpMuU2/w

With an infinitely powerful telescope and an unending search of the night sky, perhaps one could peek around the corner of a singularity 500 million light years away and see a billion-year old Earth. Just see what it looked like then, of course.

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102 Name: Anonymous Scientist : 2007-11-25 08:55 ID:6PACnZ0v


But what about the possibility that the time machine has to be stationary (a la Ronald Mallett and his "time machine")?

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103 Name: Anonymous Scientist : 2007-11-30 15:57 ID:a4NPZkeb

OK, point on the speed of a tube of ball bearings 10 light second long. It would take approx. 139 hours, assuming the ball bearings are perfectly aligned and made of steel, for the "information" that the first ball bearing moved to reach the last one.

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104 Name: Anonymous Scientist : 2007-12-02 16:51 ID:TZ2BDyKP

> Interestingly, a cylinder that is infinitely massive would be unable to be compressed, and it seems that the information of a force should be instantaneous through it, right?

You're making the usual mistake here of thinking of a "solid" as something that actually exists. "Solid" is an intuitive shorthand we use for something which is actually very, very different.

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105 Name: Anonymous Scientist : 2007-12-03 00:19 ID:MK0OTpW5


Now you question becomes, what do you mean by "infinitely massive"? Do you have infinitely massive nuclei with normal electron clouds? Do you have an infinite number of nuclei packed into a finite volumes?

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106 Name: Anonymous Scientist : 2007-12-04 18:38 ID:cTtQmPZW

Quark star? Isn't that basically "infinitely compressed", such that it is a solid piece of matter, as much as we understand matter to be? A collection of free quarks gathered together to form, essentially, a single particle of a size similar to a neutron star? If so, that material would be, intuitively at least, unable to support shock waves through it.

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107 Name: Anonymous Scientist : 2007-12-04 23:15 ID:MK0OTpW5

> isn't the inside of a black hole considered to be infinitely massive and infinitely small by some?

I imagine that's just poetic license taken by some cheap science fiction writer.

108 Name: Anonymous Scientist : 2007-12-05 06:28 ID:tbSEwcZO

Actually, cheap science books. Not that there is a huge difference...

109 Name: Anonymous Scientist : 2007-12-07 12:10 ID:E4evLiqi


That would still be entirely finite.

110 Name: Anonymous Scientist : 2007-12-07 23:57 ID:dEIbNI8R

What about 10 dimensions or M theory?

111 Name: Anonymous Scientist : 2007-12-07 23:58 ID:dEIbNI8R

In the year of '39 assembled here the Volunteers
In the days when lands were few
Here the ship sailed out into the blue and sunny morn
The sweetest sight ever seen.

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112 Name: Anonymous Scientist : 2007-12-17 05:56 ID:EtkKbyMa

I recently read somewhere (I don't remember where) that they're toying with the idea of time as a 4th dimension of space. It seems to me to make sense, but in any case, if it is, I don't think I can say yes to "Since light moves at the speed of light (or very, very close to it), from the perspective of the light (if you can imagine such a thing), would the light exist along all of its paths at once, if we ignore any time it hits a medium that slows it down?"

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113 Name: Anonymous Scientist : 2007-12-17 13:30 ID:Heaven


Time has been considered a fourth dimension of space-time for a hundred years, soon. Note, however, that that is specifically space-time, not space. The spatial dimensions are different from the time dimension, although they together form a whole.

114 Name: Mahuloq : 2007-12-19 07:37 ID:zQsajZBT

What about the 6 other dimensions of space!

115 Name: Anonymous Scientist : 2007-12-20 01:10 ID:Heaven


I wouldn't worry about them until the spring theorists actually manage to find some actual experimental evidence.

116 Name: Anonymous Scientist : 2007-12-20 15:56 ID:sW+pmhcT

But if time is a dimension then it should mean we can go back in time, and we have seen that it's highly unlikely. Therefore time can't be a dimension... or that it's a special, one-way dimension?

117 Name: Mahuloq : 2007-12-20 20:44 ID:pDElAak7

I have always thought that to defeat that paradox, when you go "back" in time, you are always just traveling to a parallel dimension, therefore no paradox can occur, fine kill the your mum in that universe, your still there and fine.

118 Name: Anonymous Scientist : 2007-12-21 01:33 ID:Heaven


It is a dimension, but it is a time-like dimension instead of a space-like one. The Minkowski metric, which describes flat space-time, contains ones for the three space-like dimensions, and a -1 for time:

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119 Name: Anonymous Scientist : 2008-01-04 15:53 ID:9AtRNDu8


i think it's more like this:

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120 Name: Anonymous Scientist : 2008-01-06 01:04 ID:MK0OTpW5

> is there any proof of paralell universes?

Not yet, and there may never be any.

121 Name: Anonymous Scientist : 2008-01-09 18:39 ID:OxZASRqc

Time-travel is indeed possible. We know the mathematics and methods of how to bend time and space. The only problem is our energy constraints. It would take all the energy of our solar system PLUS that of another to actually travel in time.

122 Name: Anonymous Scientist : 2008-01-09 18:56 ID:sW+pmhcT

So, two portable black holes? Yup, that's what John Titor was/will be using. Created by CERN's Large Hadron Collider in the near furure. Currently scheduled to begin operation in May 2008.

123 Name: Anonymous Scientist : 2008-01-09 20:46 ID:9AtRNDu8


that's just plain false. The likelihood of creating a black hole is small, like one a second, when considering the scale of time with particle physics. Next, the holes themselves would be too unstable as such a small scale, meaning they won't last, and FINALLY, even if a black whole were to be created, and be able to stick around long enough to acrete the earth, it would evaporate instantly from (they still technically unproven) hawking radiation. If making black holes to destroy the earth was that easy, some jerkass would have done it by now - or the universe would be CONSTANTLY hurling black holes everywhere.

124 Name: Anonymous Scientist : 2008-01-09 20:47 ID:9AtRNDu8



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125 Name: Anonymous Scientist : 2008-01-10 02:31 ID:sW+pmhcT

No, those mini black holes created by Man would not destroy the Earth. They probably wouldn't even sink below ground, they would evaporate. The actual danger would come from the evaporation point, with plenty of heat and radiations.
Not all black holes are stellar-size-massive. The braneworld theory predicts the existence of tiny black holes seeded throughout the universe, remnants of the Big Bang. And that thousands of them should exist in our solar system.

126 Name: Anonymous Scientist : 2008-01-11 19:11 ID:9AtRNDu8


that's what i was trying to say, but i guess i forgot to mention they were really tiny, which is important.

127 Name: Anonymous Scientist : 2008-01-11 20:12 ID:sW+pmhcT

Okay. Next, how much energy does a black hole needs to be? If we look at John Tytor's time machine manual, we see in the "Emergency procedures" section: "Unit self-destruct is pilot controlled. The singularities will automatically evaporate with a compromise in the containment field. A nuclear explosion with the equivalent of 2x megatons will detonate upon singularity evaporation."

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128 Name: Anonymous Scientist : 2008-01-20 19:30 ID:QPZM8lgA

>>Not all black holes are stellar-size-massive. The braneworld theory predicts the existence of tiny black holes seeded throughout the universe, remnants of the Big Bang. And that thousands of them should exist in our solar system.
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129 Name: Anonymous Scientist : 2008-01-20 22:22 ID:sW+pmhcT

26 June 2006

130 Name: Anonymous Scientist : 2008-01-31 10:14 ID:C7FFjEIl

I already figured out time travel. The problem isn't getting to there. It's getting from here.

131 Name: Doctor : 2008-02-01 01:48 ID:Heaven


132 Name: Anonymous Scientist : 2008-02-01 04:56 ID:sW+pmhcT

What's strange in those time-travel stories is that "space" is omitted out of the equation. Time and space are very closely related. A time machine should be able to do space traveling. Even John Titor said that the first problem they had with their time machine is that the machine would re-appear elsewhere, and it puzzled the engineers for a while (it was because the Earth is in motion, while the machine wasn't when operating.) Where are all the space travelers' stories?

133 Name: Anonymous Scientist : 2008-02-01 19:57 ID:idwUBqtg


This is a very insightful comment,... It sometimes pays of to waste time here

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134 Name: Anonymous Scientist : 2008-02-01 23:39 ID:MK0OTpW5

Not only earth is moving, the system and the galaxy are in motion as well.

135 Name: Anonymous Scientist : 2008-02-02 01:50 ID:Heaven

all motion is relative, only acceleration is relevant in this case. also, it's quite possible that earth's gravitational field might cause the time machine to follow earth.

136 Name: Anonymous Scientist : 2008-02-11 15:02 ID:idwUBqtg


Well,... Time travel could be seen as a form of acceleration in space-time. In which case some of this acceleration might result in the problems mentioned... Or not.

137 Name: Anonymous Scientist : 2008-02-15 01:16 ID:o/K6QW7l

That is very interesting. If you think of time like a space dimension, then jumping forward or backward in time faster than the rate we are going now, is like traveling faster than light. So a time machine is an FTL drive. Cool.

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138 Name: Anonymous Scientist : 2008-02-15 14:19 ID:QPZM8lgA

>>warp drives would be like going forward in time really fast. Fini.


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139 Name: Anonymous Scientist : 2008-02-15 15:00 ID:o/K6QW7l

Theory of relativity only deals with sub-light travel. I can make up whatever the hell I want to wrt faster than light travel.

Anyway, I don't know what you are talking about. Explain please.

140 Name: Anonymous Scientist : 2008-02-15 20:11 ID:GUxM/xdZ


It's hard enough to get <i>to</i> the speed of light, let alone past it. From the Usenet Physics FAQ:

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141 Name: Anonymous Scientist : 2008-02-16 11:02 ID:o2Omsbkr

However, none of that explains why time only flows in one direction

142 Name: Anonymous Scientist : 2008-02-16 17:36 ID:o/K6QW7l

As I said, that only deals with sub-light stuff and using actual down-to-Einstenian-mechanics forces. You can't just use good old classic mechanics when talking about time travel and say oh noes, FTL (faster than light) is impossible.

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143 Name: Anonymous Scientist : 2008-02-16 17:42 ID:enesCUJn

it is possible. If i get a plane to somewhere far away, i'll find myself in tomorow or yesterday, lol.

144 Name: Anonymous Scientist : 2008-02-16 18:24 ID:o2Omsbkr


>Time paradox.
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145 Name: Anonymous Scientist : 2008-02-16 19:57 ID:Heaven

>>As I said, that only deals with sub-light stuff
>>that only deals with sub-light stuff
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146 Name: Anonymous Scientist : 2008-02-16 20:19 ID:dFSPKAAa


I'm not sure that you can just turn around and move in the opposite direction through time.

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147 Name: Anonymous Scientist : 2008-02-16 21:08 ID:Heaven

PROTOP: This is a thread of time travel.

148 Name: Anonymous Scientist : 2008-02-17 01:16 ID:o2Omsbkr

You bring up the classic point of linking time and entropy. Thats fine with me, except for two things:

We use entropy to the issue because it's one of the rare physical laws which is not symmetric, and could thus explain the perceived irreversibility of time.

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149 Name: Anonymous Scientist : 2008-02-17 01:56 ID:MK0OTpW5

How do you know time only flows in one direction, or at all?

150 Name: Anonymous Scientist : 2008-02-17 04:02 ID:o/K6QW7l

How would local reversal of time work though? I tried imagining it and I just can't come up with anything that makes sense.

One, you can't just hop into a time machine and watch the world outside reverse itself. The world is huge and it will take an immense amount of energy...if it's even remotely possible, what with all the tiny atoms and energy and stuff.

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151 Name: Anonymous Scientist : 2008-02-17 12:02 ID:FQiRyXDB


We have trouble understanding time, because we spend all our life immersed in it. It's a bit like air: in the past people did not realised that air is not just space between objects, it's something in itself. Of course there were hints (water/air interface forming bubbles, winds). Nowadays it's much easier to understand air, because we see all the time applications of our knowledge of it (airplanes, etc).

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152 Name: Anonymous Scientist : 2008-02-17 12:06 ID:FQiRyXDB


Oops, I meant to say 'In a black hole the mass DENSITY is infinite,...'

153 Name: Anonymous Scientist : 2008-02-17 17:16 ID:o/K6QW7l

In my previous post, I was thinking of time as a consequence of the movement of matter and energy but that's not the case obviously, space-time and all that. So you wouldn't need infinite energy to change your perception of time outside you (or your frame of reference). You need to somehow change your frame of reference so that the outside world is reversing to you. Argh, I need to properly understand special relativity to actually begin to make a guess at this.

154 Name: Anonymous Scientist : 2008-02-17 17:21 ID:CrGUsWlF

Not necessarily. In order for it to be defined as a black hole, the mass density need only be sufficient that light cannot escape.

155 Name: Anonymous Scientist : 2008-02-17 18:27 ID:FQiRyXDB


We are both right, but at different time points,... You are right that mass density does not need to be infinite to CREATE a black hole (otherwise you'd need infinite amounts of matter and there would be no black holes). What really counts is the amount of matter bound by the gravity well. If this amount is enough to cause collapse and a singularity to occur (a black hole), then the mass density will become infinite. This is why it's called a singularity: all the mass collapsed to a single point in space, the singularity, hence mass density is infinite.

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156 Name: Anonymous Scientist : 2008-02-18 12:48 ID:sf6Yn2sp


Special relativity won't get you much. You need general relativity, and that actually intuitively understanding that may require being insane.

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157 Name: Anonymous Scientist : 2008-02-18 16:15 ID:idwUBqtg

>On the topic of time and entropy, though, I recently saw the suggestion made that maybe time itself is only a macroscopic property.

Hard to accept that,... Gravity does not play a role at microscopic scales, but space and time do. Particle accelerators show relativistic effects on time affecting the particles. So it seems it's sleight of hand to suddently consider time a macroscopic property.

158 Name: Anonymous Scientist : 2008-02-19 10:03 ID:CrGUsWlF

That, and also many kinds of subatomic particles have measurable half-lives which are extended by relativistic travel. This seems to contradict the idea that time is a macroscopic property only.

159 Name: Anonymous Scientist : 2008-02-19 14:19 ID:E4evLiqi

I think that was more specifically the direction of time being a macroscopic effect, or the flow of time.

160 Name: Anonymous Scientist : 2008-02-19 14:51 ID:o/K6QW7l

What does that even mean?

161 Name: Anonymous Scientist : 2008-02-19 15:49 ID:idwUBqtg


I don't see why direction would be macroscopic, while flow remains microscopic. That sounds like a heap of ad hoc contrived postulates,...

162 Name: Anonymous Scientist : 2008-02-19 16:17 ID:uTBmth22

ITT we get confused because we used English instead of maths.

163 Name: Anonymous Scientist : 2008-02-19 17:42 ID:MK0OTpW5

Why would you say time has a direction, or flow?
Space does not have direction or flow.

164 Name: Anonymous Scientist : 2008-02-19 19:01 ID:idwUBqtg


> Why would you say time has a direction, or flow?
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165 Name: Anonymous Scientist : 2008-02-19 20:02 ID:TZ2BDyKP


That is not what I said. I used "direction" and "flow" as different descriptions of the same thing.

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166 Name: Anonymous Scientist : 2008-02-20 14:16 ID:o/K6QW7l


167 Name: Anonymous Scientist : 2008-02-20 14:53 ID:idwUBqtg


Loud but short of arguments,...

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168 Name: Anonymous Scientist : 2008-02-20 23:01 ID:CrGUsWlF

ITT we are wholly unfamiliar with Feynman diagrams.

169 Name: Anonymous Scientist : 2008-02-20 23:30 ID:o/K6QW7l

You mean Minkowski diagrams.

170 Name: Anonymous Scientist : 2008-02-21 02:18 ID:CrGUsWlF

No, I am talking specifically about Feynman diagrams, with time as one axis and space as the other, in which one can see plots of wonderfully counterintuitive ideas like an electron bouncing back and forth in time, turning into a positron when it's traveling backwards, and annihilating itself in a flash of gamma rays, which become an electron-positron pair that is the original electron/positron.

171 Name: Anonymous Scientist : 2008-02-21 02:20 ID:MK0OTpW5

I would say time doesn't have a 'flow', because like we move through space, we move through time (if this perspective is not just a product of a weak three-dimensional brain interpreting the world the only way it can).
Unprovable philosophy and nitpicking semantics, I know, but this thread is about time travel. Complete speculation.

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172 Name: Anonymous Scientist : 2008-02-28 16:20 ID:Heaven

Wouldn't time travel backward require undoing entropy?

173 Name: Anonymous Scientist : 2008-02-28 22:46 ID:XDpQDIXS


Not if you increase entropy as you move backwards in time,... this has already been discussed ITT

174 Name: Anonymous Scientist : 2008-03-03 15:52 ID:Heaven

My bad... just asking.

175 Name: Anonymous Scientist : 2008-03-28 06:39 ID:jaX/YWTO

Scientists still believe in time to such a degree that they suggest it is possible to travel through it, just because they've discovered it's just illusional.

Time and travel is the exact same thing, "time travel" is a pleonasm.

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176 Name: Anonymous Scientist : 2008-03-29 00:53 ID:MK0OTpW5

> Scientists ... time ... discovered it's just illusional.
> illusions of colours and sounds, other things that do not actually exist.

'Scientists' have also discovered the phenomenon of your mother being so morbidly obese, the only method by which you could theoretically have escaped her reproductive organs is through thermal radiation with a black body spectrum.

177 Name: Anonymous Scientist : 2008-03-29 02:23 ID:jaX/YWTO

I guess that's your way of saying, that you think I'm wrong. Why not try to convince me instead?

178 Name: Anonymous Scientist : 2008-03-29 04:42 ID:sW+pmhcT

If time is "illusional" then space is too. So find the frequency of the illusional vibration, put it into a computer and wire someone with it. Hop, a time/space machine. :)

179 Name: Anonymous Scientist : 2008-03-30 06:00 ID:SDrd4fDR

The frequency of the illusion would be a non-physical energy frequency, there probably is no physical frequency. The only way to do it is to master astral pojection, probably. Very scientific.

180 Name: Anonymous Scientist : 2008-03-31 01:15 ID:sW+pmhcT

Well, if the person can master astral projections, then he can view the past using the Akashic Records.

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181 Name: Anonymous Scientist : 2008-03-31 04:17 ID:SDrd4fDR

that was my point. Akashic records, or, just find the past, and go hang out in it, lol. Probably just going to the past would be a better idea... you're not really supposed to use the akashic records for entertainment.

182 Name: Anonymous Scientist : 2008-03-31 04:22 ID:SDrd4fDR

Forgot to add-
The thing that had me interested was the possibility of there being an identifiable energy frequency... if someone could find that, it would maybe be a much more accurate way to time travel astrally, instead of just trying to do it, or ending up in the past somewhat randomly. Though then it seems likely that this frequency is alreadfy tied to the akashic records.... hmmm. Anyway, it sounds like something well worth looking into, for real scientists and astral projectors alike.

183 Post deleted.

184 Name: Anonymous Scientist : 2008-04-02 16:05 ID:o/K6QW7l

Hey guys, what do you think of this? Time travel is like a feedback loop connect back through a second dimension of time. And all the changes and paradoxes can be explained by changes that happen in the feedback loop until it stabilizes.

185 Name: Anonymous Scientist : 2008-04-03 08:44 ID:jaX/YWTO

this is fucking idiotic

186 Name: Anonymous Scientist : 2008-04-03 14:05 ID:sW+pmhcT

"The Cambridge physicist Professor Stephen Hawking spent much of his career attempting to prove that time travel is impossible. If it were possible, he reasoned, why have we not been visited by voyagers from the future? But he was forced to conclude that there is actually nothing in the laws of physics that prevents moving in time.

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187 Name: Anonymous Scientist : 2008-04-04 00:39 ID:o/K6QW7l

u're fucking idiotic.

188 Name: Anonymous Scientist : 2008-04-10 07:52 ID:lgK52Yx4

Time doesn't actually exist, it's just a social construction to measure change. Of course time travel is not possible. Assuming the laws of the universe holds true and applies that is.

189 Name: Anonymous Scientist : 2008-04-10 16:05 ID:h3UAXBQj

Space doesn't actually exist, it's just a social construction to measure change. Of course space travel is not possible. Assuming the laws of the universe holds true and applies that is.

190 Name: Anonymous Scientist : 2008-04-12 01:18 ID:o/K6QW7l

Physics is just a social construction. We don't really know what is going on beyond this superficial socially constructed mathematical model for what we perceive our physical universe to be.

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191 Name: Anonymous Scientist : 2008-04-12 03:34 ID:MK0OTpW5


You're just spouting philosophical rhetoric.
Which is just a concept constructed by humans.

192 Name: Anonymous Scientist : 2008-04-12 17:11 ID:QPZM8lgA

>>190 is just a social construction. We don't really know what is going on beyond this superficial socially constructed mathematical model for what we perceive this message board to be.

4-ch is just a concept made up by us for the lulz. It doesn't really exist; it's just change. Causality. Which is just a concept constructed by humans. It's just a mathematical model to explain cause and effect. Therefore, >>190 doesn't actually exist.

193 Name: Anonymous Scientist : 2008-04-12 20:04 ID:o/K6QW7l

No I am not. What I am saying is the truth.


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194 Name: Anonymous Scientist : 2008-04-13 00:36 ID:Heaven

> I can't measure time; clocks only measure themselves, not time itself. So it really doesn't exist, it's just causality.

You can change time. That alone should give you a hint that it exists.

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195 Name: John Titor : 2008-04-13 01:05 ID:ylRqS0DE

It's possible.

196 Name: Anonymous Scientist : 2008-04-13 21:00 ID:Heaven


> I can see me, so I know I exist and I can see everything around me, so I know they exist.
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197 Name: John Titor : 2008-04-14 09:14 ID:ylRqS0DE

I'm going to be visiting earlier in this thread to prove it's possible. Just thought you should know!

198 Name: Anonymous Scientist : 2008-04-14 09:15 ID:Heaven


Oh, Titor! Choice performance, my friend! Choice performance indeed!

199 Name: Anonymous Scientist : 2008-04-15 05:26 ID:Nm9Ibg3H

That still = the person and their surroundings existing. Simply in a different form and context than what was percieved, doesn't cancel out the existence. That's similar to saying that because people a few hundred years ago thought the world was flat, that their world didn't exist. It sure wasn't flat, but it definitely existed.

200 Name: Anonymous Scientist : 2008-05-09 15:46 ID:Heaven


>>It sure wasn't flat, but it definitely existed.
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201 Name: Anonymous Scientist : 2008-05-12 13:44 ID:YvDogC4N

social constructions exist, duh.

202 Name: Anonymous Scientist : 2008-05-12 18:21 ID:jxbTFocg

Could my dong be this huge if reality was fake?

203 Name: Anonymous Scientist : 2008-05-12 21:28 ID:CrGUsWlF

Roses are red
Violets are blue
Your dong's a social construction
And so are you

204 Name: Anonymous Scientist : 2008-05-14 19:48 ID:J0jYyKkj

Time travel is impossible.

205 Name: Anonymous Scientist : 2008-05-14 21:32 ID:Xgs3XmRW

Could my dong be this huge if time travel was impossible?

206 Name: Anonymous Scientist : 2008-06-05 01:24 ID:QVAqbbCX

it's possible, so, shoo, shoo! all of you am powtaytowes.

207 Name: Anonymous Scientist : 2008-06-05 16:01 ID:4dOHvLjH

Is anyone here an actual time traveler?

208 Name: Anonymous Scientist : 2008-06-05 20:26 ID:h3UAXBQj

Yes. We all are traveling in time.

209 Name: Anonymous Scientist : 2008-06-06 20:12 ID:60qRu929