Bending Light + Building a time machine

Originally posted by Motile
OK im going to say this one last time you can NOT BEND LIGHT, it is a stream of particles, its like saying how do I bend sand?

There are some aspects of lights behaviour that can only be explained if light has wave like properties. At the same time it has properties that can only be explained if it is a particle. It is now accepted that it has both properties

Wow, did you ever open a can of worms with opposing views.

Anyway, for those of you that are confused, the reason for the opposing ideas, is because the answer depends on how you define "bending" and your point of view. And, (as with most things in life), both views are correct, just from different perspectives.

You see, from a classical physics point of view:

Ask A Scientist Archive

From the point of view of general relativity and
Einstein's Equivalence Principle, light bends as a result of the curvature of space-time caused by the presence of a mass.

So Amorymeltzer is correct that:

Any body with mass bends spacetime to a degree, and thus exerts SOME negligible change upon the path of light.

probably could have stated as anything with mass can bend light, but it is really just refraction.

See Elementary Science, Bending light

When light has to travel through a material, such as water, it moves somewhat slower. Putting the brakes on the speed of light causes the light to bend as it passes from one medium (such as air) to another (such as water). This is called refraction.

************************************************************

However, from a quantum mechanical point of view Motile is correct that:

LIGHT, is a stream of particles, its like saying how do I bend sand? YOU CANT, you can only bend the path the light is taking.

because,

From a quantum mechanical point of view The limit of this bending is reached when the central mass is great enough to cause the curvature of space-time to be so great that the light bends back in a loop of limited height.

When this limit is reached one has a black hole and the limited height is called an event horizon. For more info. check out Stephen Hawkings book "A brief History of Time" or Edward Teller's book "Dark Secrets of Physics". Both have excellent discussions on these matters.

So you see, the argument is really a matter of semantic's based on the level of ones understanding. When in reality, both are correct, just from differing perspectives.

OK, that is my 2 cents. Back to the discussion. Nothing to see here. Move along.


P.S.
Can you tell I am left handed? It helps me to see that both sides oppose each other, and are also both correct!

[edit on 9-4-2005 by makeitso]

Cool thread, I cant wait to see how it ends, time travel or banned.

I wish I had something to give, I know nothing about bending light and im not going to pretend to.

Originally posted by Shadow88
how would one make an object oscillate at the speed of:
light?
sound?

Not to be obtuse, but it seems as though you may be lacking some fundamental science theory necessary for where you seem to be headed.

Oscillation is generally measured in wavelengths, not velocity.

The speed of sound is not a constant.

The speed of light appears to be something an object might approach, but not achieve, since mass would become infinite.

When you refer to "bending light", do you mean what is implied in this picture?

i dont recall referring to oscillation as velocity

also the speed of light is not constant, as it is energy, and therefore susceptable to the variables in its present environment. and so there is no terminal velocity where one cannot continue

(p.s someone asked me about this? cant remember...ah wellSpace time

o and what reason would ats have to ban this thread?? its really intriguing.

[edit on 10-4-2005 by Shadow88]

sorry but I really cant believe that you people are actually responding to this.

I too am 16, but no better than trying to make a time machine. I did, however, once decide to make a spaceship with a group of mates, but at the time i was about 7.

If the governments of the world can't do it, with there more vast ammounts of funding, how the hell will an apparently uneducated 16 year old on, at best, paper round wages and pocket money??

Post your designs regardless, they should cause quite a giggle.

At least people will learn stuff about physics from this thread.

[edit on 10/4/2005 by lucas_900]

I RESENT TO BEING CALLED UNEDUCATED

I dont see your problem. I am merely having an intriguing conversation about time travel with people from around the world.

I find it interesting! why have a massive downer on it? LET US CONVERSE ABOUT BUILDING TIME MACHINES IF WE LIKE!!!

(BTW my IQ is 147 so dont call me uneducated! (145 is considered lower genius :lol

[edit on 10-4-2005 by Shadow88]

[edit on 10-4-2005 by Shadow88]

Hey i thought this might be interesting, a bit lacking in pictures but interesting if you can be bothered to read.
Time travel for beginners
The "building a time machine" is interesting

[edit on 10-4-2005 by Shadow88]

uh huh. sure. thats why you think you can build a time machine

discussion - fine, but there's no way you will be able to build one in your back garden, with your limited resources and even more limited funding, as you suggest you are.

hurry up with those plan anyway, school starts tomorrow so I need something to cheer me up.:

Heehee although i am quite rich

and i neva sed "I KNOW HOW TO BUILD A TIME MACHINE!!!! IT DEFINATELY WORKS!!! IM GOING TO MAKE YOU BELEIVE ME"

stop being so negative geez lighten up and have a nice interesting conversation about time machine theory!!!!!

im just....researching it....i have an idea which im going to follow....and i was getting additional information from around ats

now please if you have any constructive tell me! what is the point of coming on ats and taking the pee out of everything, just because you think something is silly.

[edit on 10-4-2005 by Shadow88]

Shadow I commend you for posting this topic. I find that you have a very imaginative mind and that is a very good thing.






P.S
Shadow88 is the young John Titor!

wow someone that appreciates good clean conjecture!

Here are some interesting sites for anyone actually interested in time travel and its practical application.

Wikipedia - Time travel

Nova online - very good for beginners

Howstuffworks - well written article (Although a tad innacurate)


[edit on 10-4-2005 by Shadow88]

it has been theorised that to travel backward in time, to before the point that the actual machine was created, would be impossible because the time machine does not exist at that point - so no going back to see the dinosaurs or to ruin someones life/ future.

Shadow88, this isnt a place to write out your thoughts and waste peoples time. Write out your situation in a clear post, with any questions you might have. So far no-one has any idea of why you want to create a time machine, neither have you stated out your plans to so. As a consequence it appears, and i suggest that you are, yanking our chains.

Goto anomalies.net --forums--- time travel forum
Probably the biggest time travel forum on the net with some qualified quantum scientists as mods. You'll need to state your plans clearly though, otherwise they'l ban you, enough 'time-travellers' have frequented their forums to not take kindly to jokers.
This thread should be closed IMO unless your next post includes a reasonable description of your situation and why you want to time travel and how you plan to do so.

6.3 Bending Light

At the conclusion of his treatise on Opticks in 1704, the (then) 62 year old Newton lamented that he could "not now think of taking these things into farther consideration", and contented himself with proposing a number of queries "in order to a farther search to be made by others". The very first of these was

Query 1: Do not Bodies act upon Light at a distance, and by their action bend its Rays, and is not this action strongest at the least distance?
Superficially this may not seem like a very radical suggestion, because on the basis of the corpuscular theory of light, and Newton's laws of mechanics and gravitation, it's easy to conjecture that a beam of light might be deflected slightly as it passes near a large massive body, assuming particles of light respond to gravitational acceleration similarly to particles of matter. For any conical orbit of a small test particle in a Newtonian gravitational field around a central mass m, the eccentricity is given by



where E = v2/2 - m/r is the total energy (kinetic plus potential), h = rvt is the angular momentum, v is the total speed, vt is the tangential component of the speed, and r is the radial distance from the center of the mass. Since a beam of light travels at such a high speed, it will be in a shallow hyperbolic orbit around an ordinary massive object like the Sun. Letting r0 denote the closest approach (the perihelion) of the beam to the gravitating body, at which v = vt, we have
www.mathpages.com...

Maybe this can help.

You are right lucas_900. you must regard foward-travelling and past-travelling as COMPLETELY different sciences.

Travelling into the future is relatively (no pun intended) easy compared to travelling back in time (unless of course a universal means of moving through time was invented)

all you have to do is travel really REALLY fast bla bla bla....

to travel backward you would need to find someway to shift through dimensions yada yada (ill post the pic next it is far easier than explaining)

[edit on 10-4-2005 by Shadow88]

picard_is_actually_a_grey sorri if i have given you that impression i am not yanking your chains at all.

i am firstly inquiring about the theory of time travel
secondly any attempts to build one
thirdly i have been conversing in general about time travel etc.

im not just spouting random thoughts some of us have actually been having really deep and intellectual conversations so w/e.

[edit on 10-4-2005 by Shadow88]

Heres the idea of going back in time. roughly....
Time loop

The theory is the normally time would go in a (visually) straight line. now if we can find a way to do what the picture displays we can circumvent the passage of time and loop back to a time that to us has already occured, but is on the timeline.

on that note, given that we arent altering the timeline (because we cant!) wouldnt everything that happens ahead of us on the timeline be set, and able to be predicted. (can some psychics tap into the future timeline??) beginning to confuse myself

that picture shows how 2 places can, theoretically, co-exist and how we could reach distant areas of the universe without faster than light travel, which is impossible. It does not show how to travel backward in time. To travel back in time would be too dangerous to contimplate.

Think of this - say you wanted to go back in time to murder your mother's father, and you do so, In doing this your mother (assuming you went back before her conception) could not be born, so neither would you, and, therefore you would not be able to go back and kill your grandfather. Because of this he would not die and so you would be born and would be able to go back in time. Incertain x ammounts of repeats her. this simple example shows how some form of never ending tiome loop could be caused, and, although no one would be aware of it, would prove dissaturous because EVERYTHING in the universe would be trapped.

So, so far, we have travel faster than light and go forward (impossible), and, rtegardless, if it were possible to travel to the future it would make our existence meaningless, and would mean that we have destinys and that what we do is set, ergo, no free will. Not a pretty thought (for me at least).

It is my belief that time travel, realistically, is too dangerous to contemplate. Another problem could arise when someone goes forward in time and finds a new invention, which s/he then takes back to their time and claims as their own, thus changing the future and giving similar effects to travelling backwards through time.

im starting to get confused now