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Author Topic:   Time traveler caught on film in 1920?
onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 76 of 104 (589327)
11-01-2010 6:20 PM
Reply to: Message 74 by crashfrog
11-01-2010 5:15 PM


But there isn't anyone on Alpha Centauri.
Say there was, what would they see?
- Oni

This message is a reply to:
 Message 74 by crashfrog, posted 11-01-2010 5:15 PM crashfrog has replied

Replies to this message:
 Message 77 by crashfrog, posted 11-01-2010 6:24 PM onifre has replied

  
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 77 of 104 (589328)
11-01-2010 6:24 PM
Reply to: Message 76 by onifre
11-01-2010 6:20 PM


Say there was, what would they see?
What would who see what?

This message is a reply to:
 Message 76 by onifre, posted 11-01-2010 6:20 PM onifre has replied

Replies to this message:
 Message 79 by onifre, posted 11-01-2010 6:31 PM crashfrog has replied
 Message 80 by onifre, posted 11-01-2010 6:32 PM crashfrog has not replied

  
ringo
Member (Idle past 489 days)
Posts: 20940
From: frozen wasteland
Joined: 03-23-2005


Message 78 of 104 (589329)
11-01-2010 6:30 PM


Okay, suppose I want to travel backwards in time from 2010 to 1920. I make sure my cellphone is charged, I get into my time machine and I press the "Reverse" button. The widgets and whirligigs bend space-time until my reference frame is right beside the reference frames of those people in Charlie Chaplin's film. Then I press "Stop".
Now, how do I transfer myself from my reference frame to theirs so I show up on their film?

"It appears that many of you turn to Hebrew to escape the English...." -- Joseppi

Replies to this message:
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onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 79 of 104 (589330)
11-01-2010 6:31 PM
Reply to: Message 77 by crashfrog
11-01-2010 6:24 PM


CF writes:
But there isn't anyone on Alpha Centauri.
Oni writes:
Say there was, what would they see?
CF writes:
What would who see what?
You said no one travels back in time relative to a universal time, but relative to someone on Earth. So I asked, relative to someone on Alpha Centauri, what would they see - time wise?
If you travel back in time relative to someone on Earth, using Einstein's field equations as you have suggested, what would in be relative to someone (hypothetically) in Centauri? Remembering that Alpha Centuari is 4.4 light years away.
- Oni
Edited by onifre, : No reason given.

This message is a reply to:
 Message 77 by crashfrog, posted 11-01-2010 6:24 PM crashfrog has replied

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 Message 83 by crashfrog, posted 11-01-2010 6:36 PM onifre has not replied

  
onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 80 of 104 (589331)
11-01-2010 6:32 PM
Reply to: Message 77 by crashfrog
11-01-2010 6:24 PM


Double post
Edited by onifre, : No reason given.

This message is a reply to:
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crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 81 of 104 (589332)
11-01-2010 6:32 PM
Reply to: Message 75 by onifre
11-01-2010 6:12 PM


Re: Ok, lets actually get into this.
Are you sure that doesn't have to do with the difference in speed between the satellites and the Earth?
Yes, quite sure. That's the consequence of general relativity; standing at rest on the Earth's surface is equivalent to accelerating at 9.8 m/sec/sec.
Are you sure gravity isn't the result of curved spacetime and not the other way around?
In general relativity gravity and curved spacetime are equivalent.
No, they exist because there isn't a full theory of quantum gravity.
We can only speculate on the consequences of a theory of quantum gravity, because we don't have one. Thus you're free to suggest that a theory of quantum gravity will necessarily preclude time travel into the past, and I'm free to respond that in general relativity as we currently understand it, travel into the past is permissible under certain (practically impossible) circumstances.
Without a full QG theory this is still sci-fi.
Currently, so is a full theory of quantum gravity.

This message is a reply to:
 Message 75 by onifre, posted 11-01-2010 6:12 PM onifre has replied

Replies to this message:
 Message 84 by onifre, posted 11-01-2010 6:52 PM crashfrog has replied

  
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 82 of 104 (589333)
11-01-2010 6:33 PM
Reply to: Message 78 by ringo
11-01-2010 6:30 PM


Now, how do I transfer myself from my reference frame to theirs so I show up on their film?
You match velocity and acceleration with the Planet Earth. That puts you into the same reference frame.
AbE: Let me expand your question and correct it, somewhat - as a consequence of these timelike curves, the best you can do is get back to the origin of the curve. So, in 1929, you create a "time machine." Later, in 2010, you step into the machine. You experience time continue in a forward direction - your watch ticks from 12:00 to 12:01 - but when you get out of the machine, you're at the origin of the timelike curve, in 1929. You don't have to do anything to "get into their reference frame", you're already sharing a reference frame with the Earth of 1929 because the exit of your time machine has always been in the same reference frame as Earth in 1929.
Edited by crashfrog, : No reason given.

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crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 83 of 104 (589334)
11-01-2010 6:36 PM
Reply to: Message 79 by onifre
11-01-2010 6:31 PM


So I asked, relative to someone on Alpha Centauri, what would they see - time wise?
They'd see whatever was going on around Alpha Centari, because that's where they are. What on Earth could you possibly be asking?
If you travel back in time relative to someone on Earth, using Einstein's field equations as you have suggested, what would in be relative to someone (hypothetically) in Centauri?
What would what be "in relative to someone in [Alpha] Centarui"? Seriously, Oni, you're making precisely zero sense with these questions.

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onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 84 of 104 (589335)
11-01-2010 6:52 PM
Reply to: Message 81 by crashfrog
11-01-2010 6:32 PM


Re: Ok, lets actually get into this.
Oni writes:
Are you sure that doesn't have to do with the difference in speed between the satellites and the Earth?
CS writes:
Yes, quite sure.
Then you need to research that again, because it is actually the difference in speed of both objects (earth and the satellite).
In general relativity gravity and curved spacetime are equivalent.
Gravity is the result of curved spacetime; which is curved by mass.
I'm free to respond that in general relativity as we currently understand it, travel into the past is permissible under certain (practically impossible) circumstances.
But you are not, at all. GR is local, that's the issue crashfrog. Einstein's field equations are local and have chronology protection. The only way to get your time travel to circumvent this is by pulling the wool over people who don't understand relativity.
Your time travel hypothesis is only acheived by grossly misrepresenting relativity and not recognizing that they are local field equations.
Currently, so is a full theory of quantum gravity.
It may not even be necessary.
Semiclassical QG works fine to represent reality, and it has chronology protection. Classical relativity works fine to represent reality also, and it too has chronology protection.
A full QG theory might actually help your time travel hypothesis.
- Oni

This message is a reply to:
 Message 81 by crashfrog, posted 11-01-2010 6:32 PM crashfrog has replied

Replies to this message:
 Message 85 by crashfrog, posted 11-01-2010 7:02 PM onifre has replied

  
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 85 of 104 (589337)
11-01-2010 7:02 PM
Reply to: Message 84 by onifre
11-01-2010 6:52 PM


Re: Ok, lets actually get into this.
CS writes:
Yes, quite sure.
I'm not CS.
Then you need to research that again, because it is actually the difference in speed of both objects (earth and the satellite).
I never said that it was not the speed as well, but it's a matter of settled fact that clocks desynchronize down on Earth compared to a high altitude due to the difference in proximity to a gravity source. That's absolutely true, it's been measured by a number of space probes, and it's a consequence of the equivalence of acceleration and gravity.
Gravity is the result of curved spacetime; which is curved by mass.
No, again, they're equivalent. Look, Oni, these are elementary matters that are covered in Brief History of Time as well as other books.
But you are not, at all.
I am, and do.
GR is local, that's the issue crashfrog.
This is not at all the issue. The issue is you continuing to make dunderheaded characterizations of general relativity because of a lack of knowledge on your part. I mean you didn't even know what a Lorentz transformation was.
Semiclassical QG works fine to represent reality, and it has chronology protection.
Well, no. It's conjectured to have "chronology protection", and it's assumed that a theory of quantum gravity will uphold that conjecture (because why else aren't we up to our tits in obnoxious American time tourists?) But that's not known. And until it is you have only a conjectural basis to assert that travel into the past is a physical impossibility, instead of just an incredibly difficult engineering problem (which is the conclusion of a number of physicists.)
The only way to get your time travel to circumvent this is by pulling the wool over people who don't understand relativity.
LOL! Yes, that's exactly right, Oni - I'm a member of the powerful Time Travel Lobby trying to put one over on people, just like the oil industry or Big Tobacco. Well, it's a good thing a comedian showed up to educate us all on general relativity.
What a tool you've become, lately.
A full QG theory might actually help your time travel hypothesis.
Maybe, but unlike you I'm not prepared to draw conclusions from theories that don't yet exist.
Edited by crashfrog, : No reason given.

This message is a reply to:
 Message 84 by onifre, posted 11-01-2010 6:52 PM onifre has replied

Replies to this message:
 Message 87 by onifre, posted 11-01-2010 7:24 PM crashfrog has not replied

  
cavediver
Member (Idle past 3721 days)
Posts: 4129
From: UK
Joined: 06-16-2005


(1)
Message 86 of 104 (589340)
11-01-2010 7:23 PM


Arggghhhhhh
Bloody hell, I skip out for a few weeks to move house and all hell breaks loose. I'm still in the middle of moving both home and business, so won't be back properly for a while. But let's just clear up a few things:
CTCs are an everyday part of General Relativity. They crop up in many solutions, most famously the Kerr-Newman family of black holes, the Godel space-time, and suitably accelerated wormholes.
The Chronology Protetction Conjecture is precisely that - a conjecture. It is the observation that space-times that admit CTCs are typically unstable to perturbations (which you can understand from the idea of particles trapped on inifnite circuits of the CTC creating a diverging stress-energy)
The field equations of GR are certainly local, but that does not prevent global topological non-triviality, including black holes, CTCs, wormholes, etc.
Microscopic-scale CTCs are certainly possible within the context of the "quantum foam", should it exist. CTCs are a feature of space-time physics, not just the Einstein Field Equations (GR)
Photons do not have mass - but they do have momentum.
Lots of tripping up over various uses of the word "time". Acceleration does not make "time" "speed-up". Acceleration simply means you are changing your path through space-time. The more you accelerate, the shorter your path between two fixed events, relative to someone who travels between the two events without accelerating. The length of the space-time path is the time experienced along that path.
The dimensions of time and space are warped and curved by the presence of stress-energy (mass, momentum, charge, etc), and this too will affect the length of paths taken through space-time. Which is why the mass of the Earth affects the rate at which clocks tick.
Lorentz transformations are part of Special Relativity, not General Relativity, and have little to do with the maths/physics of CTCs (LTs are still approximately relavant in sufficiently small volumes of curved space-time)
Right, work to do...

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onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 87 of 104 (589341)
11-01-2010 7:24 PM
Reply to: Message 85 by crashfrog
11-01-2010 7:02 PM


Re: Ok, lets actually get into this.
I'm not CS.
My apologies for insulting Catholic Sci like that, I changed it.
Look, Oni, these are elementary matters that are covered in Brief History of Time as well as other books.
Lucky for me I actually sat in these classes and didn't get my info from only laymen books.
I mean you didn't even know what a Lorentz transformation was.
I think you can search this site and find that I know what it is quite well. That I ignored it because it wasn't relevant is another thing.
Well, it's a good thing a comedian showed up to educate us all on general relativity.
I wasn't always this funny. There was a time I went to college for reasons other than to tell jokes and fuck college chics - wait, I always went to fuck college chics. But you get what I mean.
What a tool you've become, lately.
Lately? Where the fuck have you been?
Besides, don't take this so serious. Geez
Maybe, but unlike you I'm not prepared to draw conclusions from theories that don't yet exist.
Ok, crashy. I see you've gotten sand all up in 'yo vagina because a comic schooled you on relativity, so I'll let you go on your way thinking you're smart and all that. Stick to debating creationist where you actually do well.
I don't pretend to be an expert on any of this, but I do have some (still) have some grasp on it. If you weren't acting like such a little whiny cunt we could actually discuss it further. But fuck it now.
- Oni

This message is a reply to:
 Message 85 by crashfrog, posted 11-01-2010 7:02 PM crashfrog has not replied

  
onifre
Member (Idle past 3028 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 88 of 104 (589342)
11-01-2010 7:31 PM
Reply to: Message 86 by cavediver
11-01-2010 7:23 PM


Re: Arggghhhhhh
Thanks for the corrections Cave. I was wondering when you'd chime in to shut us up.
Anyway, crashfrog has allowed his ego to get in the way of a interesting discussing, so I will bow out of further talks on this with him. Unless of course you wish to correct anything I wrote directly, then lets discuss.
- Oni

This message is a reply to:
 Message 86 by cavediver, posted 11-01-2010 7:23 PM cavediver has not replied

Replies to this message:
 Message 89 by crashfrog, posted 11-01-2010 8:14 PM onifre has replied

  
crashfrog
Member (Idle past 1544 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 89 of 104 (589355)
11-01-2010 8:14 PM
Reply to: Message 88 by onifre
11-01-2010 7:31 PM


People without degrees in physics talk about physics - the conclusion
Anyway, crashfrog has allowed his ego to get in the way of a interesting discussing, so I will bow out of further talks on this with him.
As I kind of suspected (and alluded to) I think we've both made total boners of ourselves on this subject. Agree to disagree? I'm no more a supporter of the reality of time travel than you are, I assure you. Can that be our common ground, at least?

This message is a reply to:
 Message 88 by onifre, posted 11-01-2010 7:31 PM onifre has replied

Replies to this message:
 Message 90 by Wounded King, posted 11-01-2010 8:33 PM crashfrog has not replied
 Message 91 by onifre, posted 11-01-2010 10:30 PM crashfrog has not replied

  
Wounded King
Member (Idle past 110 days)
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 90 of 104 (589359)
11-01-2010 8:33 PM
Reply to: Message 89 by crashfrog
11-01-2010 8:14 PM


Just look at the evidence
I'm no more a supporter of the reality of time travel than you are
But she has a mobile phone!! Are you blind!!!??eleventyone!
TTFN,
WK

This message is a reply to:
 Message 89 by crashfrog, posted 11-01-2010 8:14 PM crashfrog has not replied

  
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