Fast orbit

And since when has anyone measured the speed of light in frame (I mean feet) per second?!

Metric baby! Get with the program!

(Actually I'm only posting this, because JG summed up what I was gonna type)

How do you know that this hasn't already happened?

I know I haven't invented time travel, because I would've visited myself by now to tell me. Unless that was against the law (temporal or otherwise) or something crazy...

Well... there's only one type of object around which you can orbit at the speed of light... and unfortunately Earth isn't one of them. Well, fortunately, I guess. Otherwise we'd all get ripped apart instantly! What a happy ending.

mmmmm spaghettification....

*drool*

To everyone saying that 'time is an idea' or 'time is a concept' or 'time doesn't actually exist'..

Before 1905, most scientists would have been inclined to agree with that. There were three spatial dimensions, and 'time' was a concept used to put events in some order.
However, Einstein changed all that. Most of you will probably be familiar with relativity, and some degree of special relativity, so I'll skip straight to what is relevant to this thread. Einstein showed that space and time were not separate entities, the Universe is comprised of events in four co-ordinates. I'm also sure that you've all seen the model of the Universe as a rubber sheet, with masses placed on it, curving the rubber sheet; a massive object curves spacetime. Note, it distorts spacetime. Space is distorted, and so is time. A very massive object, such as the Sun, will distort time. I'm not quite sure whether time 'slows down' or 'speeds up' relative to a distant observer, though.. I'm inclined towards it slowing down, but I'm not quite sure.
'Time' is not just a mathematical concept, time is a physical entity that can be distorted and can be curved.

And herein lies the answer to 'time travel'. The 'twin paradox'. We covered this in a similar thread, 'travelling faster than the speed of light' - We all concluded that travelling faster than the speed of light is not possible. okay. But, luckily, we don't have to.
When you accelerate towards the speed of light, time 'slows down' relative to the rest of the Universe. A stationary observer would see you slow down - for them, time passes slower.
This is how you could 'time travel'. You wouldn't actually be 'travelling through time', you'd be slowing down time, so what you experience as a week could be a year to a stationary observer. This is the effect of time dilation.
It could very well be used to navigate huge distances within a lifetime. It would, however, consume huge amounts of fuel to maintain such a velocity, and certainly require an entirely new method of propulsion. Besides that, travelling 'into the future' is very possible.

Einstein did make one huge mistake, though, in ignoring quantum mechanics. He quite famously said something along the lines of "God does not play dice with the Universe".
He was wrong.
The Universe is random. Quark decay occurs spontaneously. Einstein's (second) greatest blunder was in neglecting quantum mechanics, but we shall not make the same mistake!


When looking for a fundemental law that suggests that time travel into the past is impossible, a few ideas spring to mind. Most notably, the 'grandfather paradox' - what happens if you go back in time and kill your grandfather?
That is a very basic and simple thought experiment that shows that time travel into the past is logically impossible. I do think, though, that the spontaneity of quark decay is evidence for why time travel into the past is physically impossible. If you travelled back in time, the quark would not decay at the same point in time, which would result in a completely different set of events from those of which you travelled from.

Bah mort, your evidence is good, but we need something new to talk about because I"ve been hearing about those kinds of stories, like hte "twin" theory and hte grandfather theory for years.

not to mention similar examples have made telivision shows famous for a long time.

But the fact is...
well.

I think Time is relevant.

We know that time travels at different rates at different speeds. I BELIEVE we know that time travels at different rates in conjunction with amount of gravity.

Basicaly time moves differently at different places.

So seriously... 10 places start at different rates at the big bang:
One is us. 6000 estimated (no clue the real #) years of human history and we measure time in 24 hour incriments, we have telescopes and the space station/shuttle/russian ship. We have 2005 science. We see other places with our own eyes in space moving from our perspective.

now.

#2 moves a hell of alot slower. By the time we're in 2005, the cave men are inventing the wheel there.

#3 moves a hell of alot faster. They have transporters and have battles with Klingons regularly because they're alot more advanced

#4 is a little bit slower. They're coming out of the industrial age, and the car is almost invented

#5 is a bit faster, Iraq is a province of the US here after the war.

#6 is a black hole. Gravity is stronger the closer you get to the center, and regardless is strong overall, sucking in light at even the seemingly furthest distances (well... in terms of the black hole). Here, the black hole is distorting stuff so much, that time is moving at a different rate in almost every section of the region due to gravity.

#7 is an empty void of nothingness. Just a space with hardly any matter at all. THis region is actually so far from the fringes of any galaxy that there is little to no light, just stars, and hardly any amtter/gravity. (yeah it's cold too). Time would be measured here if there was something or someone to measure it, but it's not happening for 48 quadtrillzion light years. It's probably moving kinda fast, but who knows.

And so on...

The point is, Time, as we know it, is relevant to the situation/place. In my opinion. It exists as a hole (IE: it exists in general), just like matter exists in large amounts in some places and smaller in others, Time moves fast in some places and slow in others.

Or... perhaps( hypothetically) I'm totally full of crap.

Yes, you're right Veger, the stuff I covered has been done time and time again. I do wish I had something new to bring to this, but I don't. I think quantum mechanics may well put a whole new spin on time travel, or it may be a whole new way of proving that it's impossible. I'm not quite sure. But a few people seemed to misunderstand some important principles, so I thought it important to go over the fairly standard 'time travel' discussions.

Your thing about time moving at different speeds at different points in the Universe....

...hmmm...

That is genuinely very interesting, actually, I had never considered that. (I didn't quite understand the list, #2,#3,#4,#5 though?)
Time dilation can be caused by gravity, so surely areas where matter is collected together, such as galaxies, would observe greater time dilation than areas where matter is collected less densely, like the space between galaxies..
..which would mean that in the space between galaxies, time would be distorted differently to within a galaxy. Again, I'm not quite sure whether it would 'slow down' or 'speed up', but it would certainly be different.

hmm! very interesting, veger.

try ~100,000y. physical evidence of Homo Sapiens uncovered in the last 5y have proven to be about that old, give or take 50k.

Ah, only off by a few 94k years.

6000 is the age of the Earth according to the Bible.

Well if it is a construct of the mind can't you go back and reconstruct it????

Time is an illusion. Lunchtime doubly so.

First of all, suppose any one of you do build a time machine. It is possible that perhaps you will realize why you shouldn't go back and tell yourself that you will invent a time machine, etc.

Secondly, it is an assumption that the speed of light is a constant. What does that even mean? Distort time? How can a speed distort time when speed is dependent on time? Furthermore, light passing through various mediums travels at different speeds, so the speed of light as a constant falls apart.

Thirdly, I don't see how you can go from shining a flashlight on a train to time travel...none of you have made a clear argument. It seems like you were told this or read about this and thought it was a novel idea but didn't really understand it so thought long and hard about it and then thought you did understand it and told yourself you did, but you didn't really because it is flawed.

Fourth of all. Time is a physical entity---chronotons? Particles of time? Ha ha. Shut up.

Take High School physics, I implore you.

The speed of light is (so far as we know) a constant. The speed of light in a VACUUM is what we're talking about.

Science-type subjects come too easily for me. They are completely unchallenging. I ruin them effortlessly.

Your obvious lack of knowledge for even the basest of physics, shows otherwise.

Obvious lack of knowledge? Please elaborate.

The whole time taking it, it was a ridiculous joke. I can't believe any of you eat it up so readily.

WE SHALL BUILD A MACHINE AND WE SHALL CALL IT FRAN

IT SHALL BE MADE OF THE FINEST CHEESE

FRAN WILL TRAVERSE THE VAST REACHES...of time

i would havw to agree. i will admit i dont have any background in physics(sp?) or spelling for that matter. but lets put it this way, if you were to draw out a timeline of my life and to ask the question could i go back to any one point on it, the answer would simply be no. time in that sense IS only a theoretical construct. if parallel universes exsited all happening at the same time but at diferent points in history, then maybee it would be possible to go back, but then even it wouldnt really be time travel, because it would not be "this" same time... thingy. yes i know i stole the plot of the book timeline... but still my point stands while it may be possible to rebuild the city of rome and possibly somehow reanimate julius cesars corps you still cant go back to 60 A.D. or whenhave you.

Just a minute, I have a call on the quandam phone.

/Obscure?

Time is just a measure or a rate, like MPH, KPH, etc. You guys are reading too far into time.

You made yourself look pretty silly with the second paragraph.. The speed of light in a vaccuum is 3.0*10^8 m/s, and nothing can travel faster than that. Yes, when light passes through a medium it slows down.. this is what we observe as refraction. I'm not quite sure what you were trying to prove with that.

The important thing about light is that it is the same for all observers:
If you were standing on a train going at 10 m/s, and throw a ball forwards at 2 m/s, relative to you, the ball is travelling at 2 m/s. Relative to someone standing on the ground, watching the train go past, the ball is travelling at 12 m/s. That makes sense.
However, if you stand on the train and shine a torch, relative to you, the light is travelling at 3.0*10^8 m/s. Relative to the guy on the ground, the light is also travelling at 3.0*10^8, (not 3.0*10^8 + 10) - the speed of light is the same for all observers. This is what makes it unique. And this is what we mean by 'constant'. I think this is a point you should read again, because it's very important and you don't seem to understand it at all.



'speed' does not distort time. Mass does. and mass does not depend on time.

You are the last person to criticise others for not making a 'clear argument'. Your argument lacked any sort of coherence, or any sort of argument either for that matter.

You may well be 'gifted', but your ideas are about a century out of date. You are completely ignoring special relativity, which has been well accepted for about 100 years.
'Time' and 'space' do not exist as separate entities. They exist together, as flat 4 dimensional Minkowski space, often called space-time. Anything that distorts space will distort time - it is distorting space-time. The concept of space-time is one I want you to understand, because that is what you, and a lot of people, are neglecting.
Fortunately, Minkowski space is very similar to 3 dimensional Euclidian space, with only one additional differential, and so is very easy to work with.

I get the feeling that you're working with very a basic scientific understanding, and though you might excell at that, there is a lot more to it.

Please read up on the Michelson Morely Inferometer experiment.

It was MEANT to measure the change in the speed of light from when the earth was moving towards the sun, and from when we were moving away from it (Imagine measuring the speed of cars while jogging next to the road, then change directions).

It failed.

It was the most famous scientific failure in history. It was meant to show that the speed of light is variable. All it proved was that the speed of light in a vacuum is constant from all points of reference. Even if you were travelling at 50% the speed of light, and then you measured the speed of photons (light carrying particles - I know that's a gross simplification, but anyway), in ALL directions around you - the ones coming at you, the ones overtaking you, the ones coming into the side of you, they would ALL be going at the same speed: 3e8ms^-1

FACT.

Anyway, return to your lives, and I shall continue with my work now

What you are neglecting, however is that 'The speed of light is the same for all observers' is a postulate. This is just a fancy scientific word for assumption. You, however, are stating it as if it were fact. The example you gave has not been experimentally proven. What you also have to consider is that the validity of Relativity hinges on said assumptions. If only one of them can be proven false, the whole Theory will fall apart.

Your argument that it's widely accepted is fallacious in its own. It's called the band wagon fallacy. There are plenty of conspiracy theories that are widely accepted as well, though they are no more valid then Relativity. Relativity is not yet a scientific law (and for good reason). So until then, for the sake of fair (unfallacious) argument, let's keep opinions/theories/ideas independent of proven facts/laws. If you keep pushing theories as facts, then there's no motive to prove/disprove them. This accomplishes the opposite of science creating anti-science. Let's keep an open mind here.

Just adding on a bit to Martyn's post:


The Michelson Morely experiment took place long before Einstein. The 19th century logic was that waves travel through a medium (water), and sound travels through a medium (air), so light must also travel a medium, a 'luminiferous aether'.
The Michelson Morely experiment was aimed at finding out more about this luminiferous aether. As the Earth moved around the Sun, it would move through this aether, and produce detectable aether winds. The effect of aether winds on light waves would be like the effect of wind on sound waves; sound waves travel at a constant speed relative to the medium they are travelling through, approximately 340 m/s. If the wind were travelling at 10 m/s, it would appear to someone downwind that sound is travelling at 350 m/s.
This was assumed to be true of the light in the aether as well.

His experiment was the most famous failure in science, and showed no evidence of any aether at all. Morley himself was never convinced of his own results, he thoroughly believed there was an aether, even though his own experiment was the first that really disproved any such medium. His experiment showed that light travelled at a constant 3.0*10^8 m/s, regardless of the motion of the Earth.

Lasers and masers have reproduced the experiment and have become commonplace.

So, Tonberry, you are in fact 118 years behind.



Are you not the 'velocital physics' person? I forget names, but you sound like it.

It's a shame maevie isn't here, I think she'd enjoy debunking your nonsense again.

If you want experiment evidence for special relativity, read up on:

* Kennedy-Thorndike experiment into time contraction
* Hamar experiment into obstruction of ether flow
* The Michelson-Morley experiment, which we've been talking about here
* Trouton-Noble experiment - torque on a capacitor

Most notably, I'd suggest you read up on emitter theory experiments, which demonstrated that the speed of light is independent of the speed of the emitter.

Friend14, the fact that the speed of light is constant for all observers has been shown many many times... I, for one, did an experiment in my grade 12 physics class that demonstrated it. So unless you can come up with a set of laws in which the speed of light isn't constant, but still looks and acts like it is... well, it's just that right now you sound like the people pushing for Creationism: "Remember, evolution is just a theory, which is not universally accepted. So keep an open mind...."

And I do like to think that I keep an open mind, but attacking a theory because you don't like it, while at the same time not providing an alternate theory, isn't going to get you many believers.

<3, sir. <3.

He's too busy playing the persecuted scientist role to care about being accepted, kyle.

If time travel was possible in the future, wouldnt we already be visited by the people from the future.

some people believe the UFOs are actually time machines:confused:

I never questioned Einstein's First Postulate. Though there are scientist that are (which is a good thing, right or wrong).

His Second Postulate, however, is a bit more trickier to effectively prove. At this time, it is not possible to take an event in two reference frames and compare them apple to apple in some type of "common frame." Relativity attempts to do this but it's always from the POV of one frame or the other, not from "outside the box" as I'd call it. All effective experiments are performed using the "outside the box" philosophy (though not always the case, since in most lab experiments, time is constant and your concept of time is parallel to that constant and they are the same in both events/objects being compared, it is possible to look at one and then the other individually, then compare). This is so that you're not starting from a subjective reference point. What makes this particular postulate so hard to compare, is that the commonality between them (the speed of light) is skewed to thier own frames of reference (and subsequently, as postulated, time is skewed in the same manner see twin paradox).

If you're going to attack me, at least read more carefully...

Wait, so now you do agree that the speed of light is constant?

Man, it's hard to argue with someone whose position keeps changing....

Anyways, I'm not trying to attack you, but your previous post was basically just saying that relativity wasn't a fact (which is fine; no theory should ever be accepted outright), except that you said it as if any scientist that believed in relativity was just "following the crowd" and not keeping an open mind.

As I said, I have an open mind, but I'm not going to stop believing in relativity until you (or someone else) comes up with something that explains the universe better than relativity does. And since all you've done is posted your misgivings about relativity, I haven't seen much in the way of a new theory.

P.S. The twins paradox isn't really a paradox. It may seem to be, but the reference frames of the twin in the spaceship and the twin on Earth aren't actually symmetric. The symmetry is broken when the spaceship accelerates (you can really only compare inertial reference frames). So the twin on the spaceship will return home and be younger than the twin that was left on Earth. I know it seems weird, but so does a lot of real stuff (i.e. quantum physics)

Interesting, if only somewhat related:

http://plus.maths.org/issue12/news/fasterThanLight/

I've never stated disagreement with it. Ever. So I fail to see how my position "keeps changin."

In actuallity, it doesn't matter to me rather it is or isn't. For all intent and purposes, it's actually easier on my end to assume that it is.

I've been told that I have that I 'don't think like everyone else does' (intended in a good way). A close friend of my described it best when he said, "Everyone's inside the box trying to figure out what's outside the box and here you are outside the box trying to figure out how to explain to everyone inside the box what you see (understand)." He's right. I have a difficult time extrapulating my thoughts together to give a clear picture of what I know. But to try to put it simply, everyone's so consumed with trying to think "outside the box" that they over look the knowledge and understanding we already have. I had a teacher in highschool that called it the "teenager effect." Simply put, when you're a teenager, you tend to take a very simplly task and complicate it. It's done on purpose (I guess it's still one of those great mysteries), it's just what they tend to do. Probably has something to do with being thorough, If I had to guess. Likewise, it's become a scientific unspoken rule, that if it's not complicated or require complicated math, it's probably not going to hold true. That's also what happend to Relativity. It started as an innocent little concept that would easily and simplicitly explained the differences when observing an event in more then one reference frame, and complicated it significantly. If you follow the Theory of Relativity in a text book, you can easily see where it begins to drift away.

My challenge to you is this. If you can take a theory. Take away a couple of the rules and still come up with the same result on your own, then the Theory is probably true. However, if you get a different result reflect and test it further. Or you can set your own (new) rules.

Take Relativity for example. Take away the second postulate. Assume light is independant of Time and Time is only a concept (or tool for measuring). Now take one of the phenomonan commonly associated with Relativity and try to reach the same result (without breaking our new rules we've established). Be open minded and thorough. Try to take all varibles into consideration. If you can't explain the phenomonan under the new rules, then the Theory probably holds true. If you can explain the phenomonan under the new rules, then a closer look needs to be made. I choosing an easy one. Like the lightning striking the box car example.

Go ahead, try it. Post your line of reasoning.

Mort, i'm sorry. It really isn't.

That's the age according to Bishop Usher and other suchlike with an unapologetic ignorance of history, hebrew grammar and culture, &c.

Given the geneological records in the bible, one can calculate anywhere from about 6k to 60k of human history [homo sapien sapien], depending on how complete the records were and other factors. The records were not holistic and different parts are listed in different areas, it's not that they were inaccurate, merely that some had more relevance to x event than y time.

Effectively "son of" or "father to" in Hebrew at that time [i don't know about now, actually], simply meant "in the line of", so "Shibolleth son of Megakudo" could be his son his grandson his great-grandson, &c.

This could easily place the flood somewhere around 40k years ago, i believe [though further abuot this should go in the Genesis thread].


As to time travel, i feel obligated to cite this:

Oh okay, Dor. I stand corrected.

Friend14, explain time dilation without the concept of space-time.

According to what I know, It's possible to come close to stopping time, but not possible to reverse.

If you went back in time, ANYTHING you did would change the future. Though... the future you'd have gone back in, would perhaps be the future that you caused...

Seems quite confusing as a concept. They explain it well in Back To The Future films...

Except for BTTF2, which has a huge plot flaw in its time travel logic.

BTTF3 has a slightly smaller one.

BTTF1, however, is a classic.

Why is it Friend14 has offered this theory many times before. And we've always debunked it. And yet he still offers it, without being to prove it or even come up with a decent 'though-experiment'.

What you're saying may make sense to you, and I can see how it does, but it's more a conspiracy theory than a postulate. You're hinging your 'theory' on the fact that nobody can prove it...no offense, but until you do find some way to prove it, I'm rather hesitant to believe you.

That being said, there's only one thing faster than the speed of light...and that's Mort. GIGGITY GIGGITY GIGGITY

*runs*