Darwinbots Forum
General => Off Topic => Topic started by: Zelos on March 02, 2005, 01:22:59 PM
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We are all familar whit the fact we humans have sent up satellits into orbit around our beloved planter, the mother of all life here, earth. And we humans have sent probes to the outer parts of our soler system. But will it ever be possible for us to travel att FTL (faster than light) speeds? there is a way to fake such enourmus speeds. In Special relativity (http://en.wikipedia.org/wiki/Special_relativity) it says time it self is slowed down when we come close to C (the speed of light, which is 299792458m/s). Like when we are at .99C (99% of the speed of light) the time is slowed down so that 1 second on the ship is 7 seconds on earth. on earth we see that the ship in question is still moving whit sub-light speed. But for those on the ship, which have a slowed down time, it seems to move FTL. But sadly for those on the ship, if they are traveling very close to C and is going to a start that is very far away they will never be able to meet anyone on earth they knewed, becouse they are all dead when the travelers has returned. But many who have seen star trek know the warp drive (http://en.wikipedia.org/wiki/Alcubierre_drive) which bend the spacetime continium around the ship. it bend it so the distance infront of the ship becomes smaller while it makes the distance larger behinde it. we also have the hyperdrive (http://en.wikipedia.org/wiki/Hyperdrive) which would enter higher dimensions to make the distances much shorter.
which 1 is most possible of these? or do you know another way? what is that way if so?
My Thought:
if you ppl ask me I think that the [you]Warp Drive[/you] is most possible. I base this on that einstein predicted that spacetme it bent when there is energy/mass present. so that tells some for the warp drive. and ive read that we might not need the "negative energy" that was proposed from the begining. what do you think guys`?
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Wormhole. Read the Algerbraist.
EDIT: And warp drive would take the energy of an exploding star every second.
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I think we'll find a way to cheat and move faster than light someday, but it probably won't be the way we think. But still, if it is invented, it'll be called warp or hyper drive because that's what science fiction tradition dictates.
Robots were invented in science fiction (in this case a polish play) long before they were in real life. Science Fiction is pretty perceptive most of the time.
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MightyPenguin, wouldnt creating wormholes take more energy than a warp drive?
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The present theory is that to open a wormhole the size of a penny would take the equivalent of converting the mass of Jupiter to pure energy.
I read that quite recently in "New Scientist" magazine
Scientists beleive that they know exactly how to do it but just don't have enough power.
:rolleyes: PY :rolleyes:
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iver ead alot about things like that, scientist know how to get like a time machine but they dont have the energy for it. very itneresting whit time travlers, sadly you cant change the past even if you get there :angry: I wish it was possible, I had a test today and I just couldnt get the last part of it right, when I got outside I figured it out :banghead: , 30seconds later, im so angry on my self :burnup: , I hope I learn somethign from this experience :lecture: :lecture:
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You won't.
It will happen time and again. It does to all of us I think.
Before and after a test you know the subject matter perfectly but actually during the test your brain turns to mush.
:lol: PY :lol:
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damn you nature who made us humans this :angry: why, why, WHY, DAMN IT TELL ME WHY WE HUMANS CANT BE PERFECT. thats why its better to be machine/cyborg, they are more perfect :evil: :evil:
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I read in youth that to make a time machine would take a long cylinder made of lots of neutron stars. Of course, this sends you back to a parallel universe's past, which doesn't really help you change the past. At best you can observe.
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The thing with the energy needed to create a wormhole is that you only need to pay it once. For a warp drive you need to pay that cost every second. That sort of expenditure adds up fast.
All you need to do to keep a wormhoel open is lace it with exotic matter.
Yes, PY, I did say "all" ¬_¬.
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yes you would need exotic matter for a wormhole, but scientists doesnt know if that exist, and to create a wormhole you need a white hole (made of exotic matter). we make a blackhole here whit normal matter which worx like a convex lens, and a whitehole at the end of the worm hole to like a spreading lens. if you have a worm hole based on black-black you get a wormhole were you get stuck in the middle, both holes is trying to eject you from the other side, but whit a black-white wormhole you have 1 which tries to eject you from the other and 1 to eject from it self, you got a end :D sadly you can go throught that hole tog et back, you need a new hole for that. and keeping a wormhole alive costs, both black/white holes is ejecting matter in form of hawking radiation. so it will die out after some time (most likly after we have decied not to use it anymore) but we also need negativ energy to keep it open, so ure still paying a constant energy price. the negative energy cost 2
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Yes you would need exotic matter for a wormhole, but scientists don't know if that exists, and to create a wormhole you need a white hole (made of exotic matter). We make a black hole here with normal matter which works like a convex lens, and a white hole at the other end of the wormhole [to like] a spreading lens. If you have a wormhole with two black holes you get a wormhole where you get stuck in the middle, as both holes are trying to eject you from the other side, but with a black-white wormhole you have one which tries to eject you from the other and one that tries to eject you from itself. Sadly you cannot go through that hole to get back, you need a new hole for that. And keeping a wormhole alive costs, both black/white holes is ejecting matter in form of hawking radiation. So it will die after some time (most likely after we have decided not to use it anymore) but we also need negative energy to keep it open, so you're still paying a constant energy price. [the negative energy cost 2]
The bits in square brackets are the bits I didn't get.
The half-life of a black-hole is long enough to negate that type of 'hole death within any reasonable time framework. And the exotic matter is the antigravity type, foo' - it keeps the wormhole open by pushing away from itself.
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Hmmm , well I am a beleaver in dreams , I think its a way of comunication , just like radio waves. I got this funny dream once that the closest Inhabited planet (with smart beings) is 35 light years away. (I might off read it from a news paper, anyway thats not the main point)
If we get atleast 1 ufo an hour arround the world somewear, Don't you think thouse ET's even from the closest Inhabited planet [you]Don't [/you] wait 35 years at light speed just to reach earth , witch (by the same reasoning) is inhabited by very simple life.
The point is there is deffinetly a way to travel faster then light , and ^ here is my prove.
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Here is an interesting question to think about.
First of all, light speed is supposed to be a universal constant. Yet relativity says that all velocity can only be measured relative to something else.
So what the heck is light speed relative to?
Another thing.
If spaceship A travels at 90% of the speed of light (which is definitely possible under Einsteins rules) and it meets another spaceship going the exact opposit direction at 90% of the speed of light then they pass each other at a relative speed of 1.8 times the speed of light.
Wouldn't you say that this proves that it is quite possible to exceed the speed of light since all velocity is relative to a point of reference.
Another example is that distant galaxies are supposed to be moving away from us at incredible speeds. Significant fractions of the speed of light. Try accelerating away from them and your combined speed will be much more than C.
There are a bunch of other unexplainable things about relativity too.
More later
:D PY :D
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PY, you have no clue about the relativity theory, don't you :)
Sorry, but it is obvious :)
Without going into details, think about it this way: don't you think that tens of thousands of scientists would not think about the example of two ships going towards each other with speeds over 1/2 of light speed? :)
I would recommend reading some very basic book about theory of relativity (just pick one in a library) - the basics are very elegant and easy to understand. And most books do consider these fun cases that seem to "disprove" the theory :)
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Relativity always made my head hurt.
The reason cestial bodies can move aparty at speeds greater than the speed of light is that the actual fabric of space is expanding. Either celestial body isn't moving greater than light speed in its frame of reference, but compared to each other they look like it.
The end effect is a doplar shift in the light's wavelength that either body recieves. Usually a redshift (I think).
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I think I read that you have to either do extremly complicated equations or measure the speed from a nonmoving frame of reference, to tell the actual speeds(all of which are less than light).
What exactly would an object going backwards in time look like to us? I heard some talk about antimattter being matter going backwards in time, but that it still can't be used to send a message since we can only observe reactions taking place in a forward direction. My guess is that time travel is possible as long as the law of conservation holds. Since matter/anti-matter are essencially opposites it should balance out. But I'm not exactly planning on volunteering to be turned into explosive anti-matter anytime soon :)
Maybe, like PY says, we're really in a giant computer and all we need to do is to find the savegame file somewhere. Who knows?
Endy :blueblob:
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when tis about the special relativity and 2 ships moving at 0,9c and are moving toward each other, there is a formula which tells us they will only see that the other ship is moving whit 0,99C or something like that. nothing can move whit the speed of light relative to anything. and the speed of light is always the same relative to everythingand endy, antimatter is like ordinary matter, but it have the opposite charge, a proton is -1 and a electron (positron) is +1, you get it?
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I think I read that you have to either do extremly complicated equations or measure the speed from a nonmoving frame of reference, to tell the actual speeds(all of which are less than light).
Trouble is there is no such thing as a non-moving frame of reference.
I remember a simple example that my college physics proffessor showed us once to demonstrate relativity and why time is the variable rather than light speed. You have to have a pretty good imagination for this.
There is an observer on an asteroid who watches a spaceship fly past at high speed.
On board the spaceship is another observer who carries out an experiment to measure the speed of light. he fires a light beam from one side of the ship to the other, where it hits a mirror and returns to a detector at the source. He knows the distance travelled and he measures the time taken so he can easily calculate the velocity. Distance = twice the width of the ship. Time = t. Go figure.
The observer on the asteroid is able to watch the beam of light that traverses the spaceship and makes his own measurements of it. To him the light beam doesn't simply cross the ship and back in a straight line, It travels diagonally as the spaceship is moving. Let's say the ship is moving at the correct speed for the light beam to be moving at a 45 degree angle to the perpendicular.
From the asteroid observer's frame of reference, the light beam travels a much greater distance than it does for the observer on the spaceship. he measures that distance as 2 * the square root of (double) the square of the width of the spaceship using simple trigonometry.
He calculates the speed of light from his time and distance measurements.
According to Einstein, both observers will measure the speed of light to be exactly the same.
We know that the light beam must actually be moving in the way that the observer on the asteroid sees it since the ship is in motion. It is logical that the light beam must be moving with the direction of the spaceship's travel and not just side to side since it takes a finite time to complete its trip.
Therefore, in order for the observer on the spaceship to measure the speed of light to be the same universal constant, his time must be moving slower than that of the observer on the asteroid. (relatively)
Everybody follow this still?
I will leave it at this point before carrying on. More later.
:D PY :D
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Makes perfect sense to me. I guess the question I have here is how these two guys know which one is moving and which one is sitting still? It might as well be that the ship is stationary and the asteroid is passing by :)
Also, on the practical side of things: these two dudes seem to observe and measure the speed of light without any special equipment. In real life they'd be somewhat distanced from the beam of light in question and will use some physical phenomena to a) measure the distance the light travels and B) measure the time. These measurements would introduce another level of calculations and make the problem really complicated! I'm glad I'm not a physicist to figure all this stuff out :)
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Makes perfect sense to me. I guess the question I have here is how these two guys know which one is moving and which one is sitting still? It might as well be that the ship is stationary and the asteroid is passing by :)
Also, on the practical side of things: these two dudes seem to observe and measure the speed of light without any special equipment. In real life they'd be somewhat distanced from the beam of light in question and will use some physical phenomena to a) measure the distance the light travels and B) measure the time. These measurements would introduce another level of calculations and make the problem really complicated! I'm glad I'm not a physicist to figure all this stuff out :)
Exactly right.
It all makes perfect sense within th eprecepts of relativity.
And there is no known way that these observers could actually measure the stuff in this way. You have to assume a few things here but they shouldn't change the fundamentals of the equations.
Your point about the relative speed of the spaceship and the asteroid actually lead on to my next point which is where a lot of this logic falls apart for me.
Let's imagine that the asteroid is actually a second spaceship going the other way. It too has a little guy doing a light beam experiment as well as watching the other guy's light experiment through some kind of subspace observation module or something.
In this scenario both observers will see time slowing down for the other observer while their own stays the same.
If both ships travel in a wide circular path and eventually meet again while constantly observing each other (again with the imaginary subspace instant communications module), each one should see the other as being much younger than he is himself. Eventually, each observer will see the other one remain young while he himself dies of old age.
This is somewhat of a paradox that I just can't get my head around.
I realize that a wide circular path means an acceleration is applied which could change things according to special relativity so let's assume that this path is an orbit of a large black hole or something so that the gravity will exactly cancel the acceleration of travelling in a circle.
How do you square these observations with each other?
:blink: PY :blink:
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talking about relativity? sweet I love how this evolve. well when it comes to the timedilation that happen when you begin to reach speed close to light can easly be calcylated whit this formula:
T2=T1/root(1-(V/C)²)
where T2=the time for us
T1= the time on the ship
V=velocity of the ship
C=speed of light
so lets say they are moving at 99% of the light, their time will then be slowed down so that 1 second for them is 7 for us. but both is still moving whit the same speed relative to the blackhole on question they are orbeting. but to reach this speeds they need to be very close to the blackhole. So now of a suddenly the timedilation from gravity become important, the formula for that is:
T2=T1/root(1-(R1/R2))
where T1/T2 is the same as whit speed
and R1=Schwarzschild radius (the place where the escape velocity is C, nothing can from here return)
and R2 is the distance from the center of the blackhole.
but both cant be older for each other and still be young to it self. where have you heard that? I would like to read it, but I dont think that is possible, coz what happen then when both stop moving? they are younger compared to each other, and still older compared to each toher, its not possible to be older/younger compared to both. but if you can show me where you read it I´ll gladly read it
:lecture: zelos :lecture:
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its not possible to be older/younger compared to both. but if you can show me where you read it I´ll gladly read it
I didn't read it. it is an exercise in logic. just think it through.
Also these observers don't need to be anywhere close to the speed of light and they could be orbiting the entire universe rather than a black hole. It doesn't matter.
Each observer sees his own time as normal and measures light speed at C.
Each observer also sees light moving further on the other spaceship than the observer on that spaceship does.
Therefore each observer sees time moving more slowly on the opposite ship than it does on his own.
Inference: The observer will grow old and die while the other won't.
This clearly can't be correct.
I can't see anything wrong with the logic so what is the deal here?
:wacko: PY :wacko:
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well, if they have the same speed compared to the same thing they will never become older compared to each other. they have the same flow of time. if they dont have the same speed or are compared to different thing one will have a slower flow of time and will be younger when they reach the same speed to compared to the same thing
:lecture: zelos :lecture:
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PY, I found a web-site that explains special thoery of relativity in very simple terms: http://www.phys.vt.edu/~takeuchi/relativity/notes/ (http://www.phys.vt.edu/~takeuchi/relativity/notes/)
You should check it out. The question that you posed is a variant of the old "twin paradox" and it is explained right here: http://www.phys.vt.edu/~takeuchi/relativit.../section15.html (http://www.phys.vt.edu/~takeuchi/relativity/notes/section15.html)
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In the (x,t) frame, the apple is hit after the arrow was shot. In the (x',t') frame, the arrow being hit and the shooting of the arrow occur simultaneously. But in the (x'',t'') frame the apple is hit before arrow is shot!. How can this possibly happen? This contradiction occurs because we allow the arrow to travel along the line connecting A and B which requires the arrow to travel at a speed exceeding the speed of light.
Bs , Even if arrow travels faster then light, The abserver will see apple being hit after he launched the arrow: why? Simple , because light is slower then the arrow it talkes more time for light to travel from the apple to the abserver then for the arrow to the apple.
aye , lets look at another example: wth does instantaneous communication have to do with faster then light travel? And even if there was sutch a thing then distance and speed of objects wont matter.
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PY, one gets old and dies because time from his perspective and that of his body is actually going faster, as I understand it.
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But do I have a point here or what? Or is my english so bad no one can read it? I mean who is going to argue with 50 years of physics? right?
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Depends how much faster the arrow is going than light, I suppose. And you can only communicate instantaeneously if the carrier medium can move the information from point to point instantaneously; I.e. faster than light.
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Depends how much faster the arrow is going than light, I suppose.
Lets do a picy:
:shoot: ------------------------------------------------------------------- :help:
light reached here in <-- 20^202 years because its too far <-----------
----------> too fast arrow -----> reached the target in 1/10^10 a milisecond
means the guy had to wait a nice 20^202 years - 1/10^10 milisecond witch still about 20^202 years.
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And you can only communicate instantaeneously if the carrier medium can move the information from point to point instantaneously
If you are not moving the information from point to point instantaneously then you are not communicating instantaeneously. duh. Then its not called communicate instantaeneously
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Let's consider that (as far as I know, it sounds a bit dodgy to me) an object moving faster than light is technically going backwards in time.
So in theory the arrow could arrive 20^202 years + 1 second before you fired it, and you would see the arrow hit before you fired it.
EDIT: Bots, you asked what comunicating instantly had to do with ftl. I told you.
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But what happend to that " inertial frame " rule
The Twin Paradox
suddenly stuff like that dont apply ?
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You lost me. You're talking to a guy who is working from a basis of second year high school physics and cool shit scrounged from the odd science book/journal.
EDIT: I wikied it and I know what you're talking about now. Tell me what the paradox has to do with arrows moving backwards in time.
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lol you say: "an object moving faster than light is technically going backwards in time" Well no, an object moving faster then light only ages slower so it has nothing to do with it.
So I say: "New Twin Rule"
Lets make more stuff up :)
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TIME SLOWS DOWN AS YOU SPEED UP. AT THE SPEED OF LIGHT, TIME STOPS. IF YOU GO BEYOND C, TIME REVERSES. DO YOU UNDERSTAND?
THIS IS NOT SOMETHING I MADE UP. THIS IS SOMETHING I READ.
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ok sorry , I did not know that one.
Now all I need to do is figure out what happens after time stops , no one knows that, They think things go backwards in time, but who knows? I know now , the gods get an overflow error of some sort ...time to edit that universe code again.
Well now the stuff about light behaving like waves as well as particals makes sense.
New time past compered to old time 1 second past = 1second * (1 - (speed^2/lightspeed^2))^0.5
:blink: :wacko: :(
Now how am I supposed to program my vedio games, I dont want to have maid up physics but it apperars I have no choise...
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Technically people aren't sure what happens if you managed to go faster than light. It'd undefined behavior. The mathematical model says you'll go backwards in time, but the mathematical model wasn't designed to extrapolate like that.
Time dilation is something like this:
1/(1 + (v/c)^2)
or something very similar
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Which is why it always seemed iffy to me.
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PY, one gets old and dies because time from his perspective and that of his body is actually going faster, as I understand it.
Exactly
But the other one does exactly the same. they both get old and die before the other one does.
:blink: PY :blink:
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well, if they have the same speed compared to the same thing they will never become older compared to each other. they have the same flow of time. if they dont have the same speed or are compared to different thing one will have a slower flow of time and will be younger when they reach the same speed to compared to the same thing
:lecture: zelos :lecture:
Everything has the same speed with respect to something.
You can cross reference every atom in the universe and find that every one can be said to moving at the same relative speed to some point somewhere. Then that point can be calculated to be moving at the same speed as another point, relative to yet another point. The whole lot would eventually cancel out in such a way that time dilation isn't possible under any circumstsnces.
That would make the whole of relativity superfluous and completely pointless.
My point is that from each of my two observer's frames of reference, they are the one who is going to die first while the other one stays young.
Let's just assume that there is a method of instantaneous communication over infinite distances, wormhole, subspace, whatever. Distance and speed should be completely irrelevent if the two observers are able to carry on a video conference with each other all the time.
In this case then each observer would see the other remain young while he himself aged.
It doesn't make sense.
:wacko: PY :wacko:
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You should check it out. The question that you posed is a variant of the old "twin paradox" and it is explained right here: http://www.phys.vt.edu/~takeuchi/relativit.../section15.html (http://www.phys.vt.edu/~takeuchi/relativit.../section15.html)
Actually this isn't a version of the twins paradox since no change ever occurs in either observer's inertial frame of reference.
The twins paradox requires the twin on the spaceship to accelerate away from the (relatively) staionary twin and later to accelerate back towards him.
In my example I propose that both observers continue on in a completely unaltered straight line for eternity. All I need is a hypothetical method to instantly comunicate between the two for them to directly observe the aging phenomenon.
Of course it isn't actually necessary for them to observe it for it to happen.
Each observer ages faster than the other whether they actually see it or not.
"But they are each in a different frame of reference", the argument goes.
So what? This only means that the two frames of reference are at direct odds with each other. They cannot logically both exist since in each of the two frames, the observer is dead long before the observer in the opposite frame is.
I have been through all the math and all the logic I have spoken to supposed experts in the field and I have never got a satisfactory explanation for how this can be.
:blink: PY :blink:
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No, PY, it is exactly the same situation. If these two guys are observing each other from distance, each of them will see that the other is aging slower (first part of twin paradox scenario). There is no contradiction. But if they want to get together and compare their observations right next to each other, then at least one of them will have to brake and reverse direction. At that point, it will look to that guy (who is braking and then accelerating) that his twin suddenly grew very old. The simmetry is broken, because they are not in innert systems anymore. Read that website, it does explain the whole thing pretty well and is quite short to go through in 15 minutes :)
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Relativity made sense to me in highschool. I've since lost it, but I remember it used to make sense to me. It's not an intuitive system, but it does solve alot of problems. More than it creates.
If relativity is false, it is false in the same way newtonian physics is. It's a special case.
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each of them will see that the other is aging slower
I think I just came up with a good example how this can be and not be a contradiction. Imagine two guys standing on sphere, but they don't know they are on a sphere. They come close to each other and measure up - both are six feet tall. Then they move apart. They use instruments to measure each other's height. Due to the curvature of the sphere it will appear to both of them that the other person is getting shorter.
This situation does not exactly replicate the situation with twins, but I just tought that it gives a good example that sometimes reality depends on your point of view.
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But if they want to get together and compare their observations right next to each other, then at least one of them will have to brake and reverse direction. At that point, it will look to that guy (who is braking and then accelerating) that his twin suddenly grew very old. The simmetry is broken, because they are not in innert systems anymore. Read that website, it does explain the whole thing pretty well and is quite short to go through in 15 minutes smile.gif
But there is no acceleration since they never stop moving or ever come together.
They don't need to. Both frames remain totally unchanged.
They are using a hypothetical, might exist one day, system of instant communication over infinite distance.
The twins paradox is completely different. In that there is acceleration which then kicks in special relativity.
In my case, there is no acceleration whatsoever so general relativity covers it.
:wacko: PY :wacko:
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Well, the whole point of special theory of relativity is that "instanteneous" events are not possible, because no two observes can agree on when a given event occured. Instanteneous would mean that they did agree.
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So that would make any kind of wormhole travel impossible then.
I understood that instantaneous travel was theoretically possible.
here's another slant on it.
One of my observers goes through a worm hole and comes out in front of the other one.
They pass each other again at the same relative speed but without either one ever undergoing any kind of acceleration.
When they pass this time they should both be older than the other one.
That satisfies all the criteria for the paradox.
:D PY :D
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I doubt special theory of relativity even considers things like wormholes. Besides, if wormhole moves an object instanteneously in space, it would also move it in time. So the dude that goes through wormhole will travel in time and may not necessarily be older than his twin. Maybe going through wormhole will throw him back in time many years.
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You are right that relativity doesn't even consider the existance of worm holes. At least I am pretty sure it doesn't.
I think (though I might be wrong here) that Einstein himself postulated the existence of wormholes.
Wormholes are still a bit of an unknown but I don't think it is inevitable that time travel is also included in wormhole travel.
You have to see though that for my example to happen with no associated shift in time then we would have a REAL paradox that couldn't be reasoned away.
This leaves us with two posible conclusions
1 Einstein was wrong and relativity is bollox.
2 Wormholes are physically impossible.
Take your pick.
:D PY :D
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3) They move you through space and through time. After all, these two are tightly linked together.
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If relativity is false, it is false in the same way newtonian physics is. It's a special case.
Yes you are probably right here.
There is no doubt that relativity and all the equations that go with it, can be used in all of the situations that we have so far tested it in. We have never yet even come close to testing it in a situation which could make it fail.
However, it is well known that in certain circumstances, relativity disagrees with quantum mechanics.
It is impossible that both are 100% correct.
Newtonian physics is rather simplistic but serves well enough in every day situations.
Relativity is useful in 99% of circumstances but I have a lot of nagging doubts that when we are able to really test it, we will find it to be a pile of bollox.
Quantum mecahnics make a whole lot more sense and appears to be applicable in a lot more situations.
:D PY :D
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if wormhole exist we have time machines, coz if the 2 ends are moving in a different rate throught time they will be spereted not only in space, but in time 2. if let us say that 1 opening is in a orbit around our sun at a distance of plutos radie. and the other end is close to a neutron star, or moving whit speeds close to light. they will be seperated throught time, and woila, we have a time machine, but we still cant change the past, and if you ask me, relativity and quantum mechanic give as much sense both, sometimes I think relativity givers more
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hmmm--- Well what happens to an object that is moving near light speed and it Emits light, does this light go slower in one direction (to the abserver moving at near light speed) or not? (Light have to travel at a fixed speeeed)
:lol: Bau :lol:
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it moves at the same speed in all directions. if that object is moving ,99C compared to earth we will only see it slow after slithly every second, but for this object the light is moving C metres from it it all directions every second
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It travels at the same speed for all observers. It has been tested in numerous experiments, and the whole general theory of relativity has been done to incorporate this observation into physics.
I say it's just a bug. whoever was coding our universe just forgot to apply newtonian physics to light :)
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"It travels at the same speed for all observers." How is that possible?
Here is another picture:
--------( L1<----A---->L2 ) ------>
B
For A to abserve that the light is traveling the same speed
L1 = speedA - speedoflight
L2 = speedA + speedoflight
For B to abserve that the light is traveling the same speed
L1 = -speedoflight
L2 = speedoflight
Note:
-speedoflight != (speedA - speedoflight)
speedoflight != (speedA + speedoflight)
gg laws, or what?
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So here is another little conundrum.
It is supposed to be impossible for any observer in a box to be able to tell anything about the outside world by means of any experiment that he does that remains entirely inside the box.
He cannot perform any experiment that interacts with anything outside the box in any way.
Supposedly, he cannot ever know how fast the box is moving provided it does not undergo any kind of acceleration.
This is a very well known scientific law that is taught in pretty much every physics class.
This doesn't sit well with relativity.
Think about this scenario.
The observer has a mechanism consiting of a laser that is able to emit a beam of light in a specific direction and at a specific wavelength, and a very narrow detector which is able to detect a photon of the specific wavelength of the laser.
Any change at all in wavelength or trajectory will cause the photon to NOT be detected.
If the observer rotates the mechanism then starts it going, he is going to see diferences if relativity is correct.
If the beam of light is being emited in the direction of travel then the wavelength is going to be blue shifted at the detector.
If the beam of light is being emited opposite to the direction of travel then it will be red shifted. Just like light from distant galaxies is.
if the beam is perpendicular to the direction of travel then it won't ever hit the detector at all since the box (and therefore the detector) will have moved out of the way by the time the beam gets there.
The only way the beam could hit the detector is if the photons are moving with a velocity relative to the laser source rather than at a universal speed.
Remember these photons are being ejected from the laser perpendicular to the direction of travel so they will not be imparted with any forward velocity at all. They will be moving in a straight line from the position that the laser was when they were fired.
So which LAW of physics is right and which is wrong cuz they can't both be right.
:sly: PY
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Guys, seriously - read the website that I posted above! It goes over these questions!
Bots - theory of relativity explains how it is possible. The whole point of theory is to explain this strage fact.
PY - there is not going to be any change in wavelengths frequency. For observer in a box everything is going to look as if he were standing still. Look at the example with the train in the web-site I listed above. It is a similar idea.
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PY, are you actually a physicist, or one of these crazee internet people who just pretend because their actual lives amount to sod all? I'm beginning to wonder... ;)
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For observer in a box everything is going to look as if he were standing still
I know that is what is supposed to happen. I just don't buy it!
for there to be no frequency shift, the distance between the source and detector must remain in the same proportions to the velocity of the light beam.
Oh Crap! :(
I just figured out that the frequency change at the detector will be cancelled out by the frequency change at the source so this won't work anyway.
Still doesn't explain the perpendicular example though.
And yes I have read the information at the site that you linked. I have also read bunches of textbooks and taken university level physics courses about the subject.
No book and no Physics professor has ever managed to fully answer my questions. All the answers I get just use circular reasoning. Relativity says this will happen so this is the reason why that happens. All the explanations are based on the assumption that relativity is correct. Nobody is willing to put a foot outside the box.
I even had a physics proffessor who told me that if I could prove that Einstein was wrong then he would kill himself because he had wasted his entire career.
"What a complete twat!" I thought. Nobody with that attitude should be allowed to call themselves a scientist. Science is about pushing the bounds of knowledge, not sticking to some religious notion that what we know is what we know "so just deal with it!". That is the attitude I always come up against.
Let's all bow down to the great God Einstein :pray:
:angry: PY :angry:
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Nice smiley, PY
You are right about the professor - this kind of attitude is a shame for a scientist. It is the reason why some people believe that science is a sort of religion.
One thing to remember though - theory of relativity appeared to explain an already observed fact - that speed of light is the same for all observers in inertial systems. You may not buy the theory, but you have to accept the fact :) And explain it somehow :)
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schvarz, why does light have to be ruled by newtonia physics? relativistic is good as any, relativity does alot of sense.
all speeds are different relative to different things, exept the speed of light which is the same relative to everything
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zelos: I can't quite place your post. Is this a question or a comment? What are you trying to tell me here?
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im trying to tell that relativity does make as much sense for speeds close to light as newtonia do for speeds belowe 0,1C, and the "all speeds are different relative to different things, exept the speed of light which is the same relative to everything " is just a comment that is true, think it matches in this topic
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OK....
But why are you telling me this? I never argued with this.
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just got the picture you did
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One thing to remember though - theory of relativity appeared to explain an already observed fact - that speed of light is the same for all observers in inertial systems. You may not buy the theory, but you have to accept the fact And explain it somehow
This may just be me being out of touch but I haven't actually seen any incontravertable proof that the speed of light actually is the same for all observers in inertial systems.
Do you have any links to actual experiments in which this has been observed? (particularly before Einstein came up with the theory)
I don't actually know of any but as I said, this could just be me being out of touch with physics research papers.
I know they did some experiment with an atomic clock on a fast airplane that circumnavigated the world. while its twin stayed behind. The claim was that they read different times afterwards but if they did then it kind of screws up the explanation given for the twins paradox.
More than likely, the acceleration, different air pressure, magnetic fields or whatever, messed with the workings of the clock on the plane so that it didn't keep accurate time during the trip.
:D PY :D
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I do know that mercury's observed orbit was off from its newtonian orbit, and that relativity helped explain it just about perfectly.
There was another thing too, another celestial event, that occurred just a bit after Einstein released his theory but I don't remember what it was.
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In the same website: http://www.phys.vt.edu/~takeuchi/relativit.../section07.html (http://www.phys.vt.edu/~takeuchi/relativity/notes/section07.html)
he is talking about Michelson-Morley experiment. I am not a physicist, so I can't tell the details and setup and validity. I just assume that scientists who did this knew what they were doing. I also assume that many similar experiments have been performed many times after the theory has been put forward. Or at the very least that many experiements relied on the fact that speed of light is constant for all inertial observers and got the expected results.
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I will go back and read your article again to see if I can find specifics.
By my understanding though, there is no experiment that we are able to do in which relativity comes up with a different answer than Newtonian physics.
In order to see any divergence we would need to be travelling at a very significant fraction of light speed.
We simply don't have accurate or precise enough instruments to tell the difference at the speeds that we are able to travel.
Num: I haven't heard about this Mercury orbit thing. Do you have any references?
:unsure: PY :unsure:
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ahhh ic , light is really traveling on the same speed, but because the abserver on the ground is in a "different time frame" it "seams" to him that the speed of light is different for bouth directions.
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PY, try this (http://archive.ncsa.uiuc.edu/Cyberia/NumRel/EinsteinTest.html) out.
I think that's what I'm talking about. Second section entitled 'Mercury's Changing Orbit'.
Also, I think there have been some tests using the mirror on the moon to test the idea of the speed of light being constant for all intertial frames. Could be wrong though, I'm not a scientist.
Bots, are you talking about the Ether? Because that was proved wrong later, which is why they needed relativity.
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No I am quoteing some of my comprehansion of the link shvartz posted, just never mind or somthing.
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The ETHER was never actually proved wrong.
Using this contraption
(http://upload.wikimedia.org/wikipedia/en/thumb/a/ac/325px-Michelson-morley.png)
The Michelson Morley experiment showed that there was not the expected flow in the ether on the surface of the Earth. They did, however, measure some differences.
This discepency could be explained either by relativity or by the Fitzgerald-Lorentz contraction.
Another possible solution was found in the Fitzgerald-Lorentz contraction. In this theory all objects physically contract along the line of motion relative to the aether, so while the light may indeed transit slower on that arm, it also ends up travelling a shorter distance that exactly cancels out the drift.
Other suggested reasons for the results include the magnetic field of the planet dragging the ether along with it. After all we know that gravity effects light.
And even to this day there is a small difference noted when the experiment is repeated with modern lasers over much longer path lengths. They just don't match up to the effect expected by the presence of a universally stationary ether.
The ETHER theory has now been all but abandoned in favor of relativity even though, with certain ammendments, it can explain pretty much everything as well as relativity can.
:D PY :D
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btw I was never talking about an "ether" theory...
http://www.phys.vt.edu/~takeuchi/relativit.../section09.html (http://www.phys.vt.edu/~takeuchi/relativity/notes/section09.html)
there, now thats what I was talking about in the lest 2 posts here.
B) Btw Py how did you paste a picture? For example: I want to draw somthing in paint right now and post it, how would I do that? Is it even possible? B)
:ph43r: Bau :ph43r:
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btw I was never talking about an "ether" theory...
http://www.phys.vt.edu/~takeuchi/relativit.../section09.html (http://www.phys.vt.edu/~takeuchi/relativity/notes/section09.html)
there, now thats what I was talking about in the lest 2 posts here.
B) Btw Py how did you paste a picture? For example: I want to draw somthing in paint right now and post it, how would I do that? Is it even possible? B)
:ph43r: Bau :ph43r:
You click on the button labelled "IMG" and paste or type in the URL to the picture that you want to display. This only works for web hosted pictures and not from your own PC.
something like this picture taken by the hubble space telescope.
(http://imgsrc.hubblesite.org/hu/db/2004/07/images/a/formats/thumb.jpg)
:D PY :D
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Bots
What you have there in that link is a hypothetical situation predicted by relativity and passed off as fact.
This has been my problem all along.
Relativity predicts stuff but nobody has ever satisfactorily proven that it happens.
Your observer in the car has no real way to measure when the light beam hits either the front or back or the train so it can't be proven.
The observer on the train can't actually measure it either.
Besides which, a train doesn't move fast enough for there to be a measurable difference any way.
What if light is moving relative to its source rather than at a universal constant? It more or less explains the anomolies of the Michelson Moreley experiment.
:D PY :D
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Any system that replaces relativity has got to explain:
1. Black holes. Predicted by relativity (although Einstein hated the idea) have been seen (not the hole itself, but the xrays of excited particles entering the event horizon).
2. Mercury's orbit. See the link I posted earlier.
3. Doplar shift of light from celestial bodies moving > c relative to us.
And a bunch of others. My opinion: if it looks like a duck, sounds like a duck, and smells like a duck. It's probably a duck.
Bots, try image shack (google it). They host images for free.
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why they abonded ether was that it wasent needed in the relativity, but if it had exist it would create friction in space, and there is no friction in space, thats why you just keep moving for ever unitel you hit something
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Ether had some funny properties.
It had to be very viscous (that's why the speed of light was so high) but frictionless to explain planetary movement.
Of course, it's not necessarily odder than relativity, but relativity does have a few observations on its side.
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Forgot to check your site earlier Num.
Just went in and had a look. Very interesting stuff.
I totally agree that anything that replaces relativity has to explain all the things that relativity does. That is the nature of science. One theory surpasses another simply by explaining stuff a little better than the last one did.
I don't disagree that relativity explains a lot of stuff very well and I don't actually think it is wrong per se.
My objection is more to the attitude that surrounds it. There is a massive reluctance to entertain the notion that maybe something else can also explain stuff and maybe even do it better.
At the first sign of anyone suggesting such a thing, the defences come up and they set out to prove that Einstein was right.
I have seen it so many times.
The point is that when doing an experiment of any sort, you don't set out to prove your point. That is going into it with a biased frame of mind so answers that are borderline will be given the benefit of the doubt and some answers that could conceivably point the other way may be discarded as outliers.
To do real science, you have to be completely unbiased or the results will be meaningless
How many papers or web sites have you seen that are actively defending relativity. From my experience, most seem to do this. The researchers are so convinced that relativity is 100% correct that they become blinded to other possibilities.
Maybe they are right, at least most of the time, but then again maybe they are missing something else that explains it all even better.
For one thing, we know that relativity doesn't apply in all situations since it comes into direct conflict with QM in certain cases. It isn't the be all and end all of science.
It is a useful tool. Nothing more and nothing less.
Just because something looks like a duck, walks like a duck and sounds like a duck doesn't necessarily make it a duck.
Maybe it's a decoy and you are about to get shot through the head by an irate hunter.
:D PY :D
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Hey check this out.
Just googling around to try to find out a bit more about "emitter theory" and how it was disproved and came up with THIS (http://www.norbertfeist.de/english.htm#Absatz1) which later led me to THIS (http://home.tiscali.be/leo.gooris/mich/)
Interesting sites claiming to show the error in the MM ether experiment.
For those of you who enjoy MATH, go work through it to see if it makes sense. I can grasp the concept and it seems to go along with what I was trying to get at earlier, but as far as the equations go :blink:
I might as well be reading chinese.
Math makes my brain hurt :wacko:
:D PY :D