Saturday, February 24, 2007

TIME TRAVEL

WHENCE THIS CREATION HAS ARISEN - PERHAPS IT FORMED ITSELF
OR PERHAPS IT DID NOT - THE ONE WHO LOOKS DOWN UPON IT, IN THE
HIGHEST HEAVEN, ONLY HE KNOWS- OR PERHAPS EVEN HE DOES NOT KNOW.

-- THE RIG-VEDA

People who have seen the movie- time machine will defenately remember the time machine used in the movie, the one with some rotating semi sphers.. Perhaps a practical time machine would be similar.

Light consists of particles called photons. Energy of these photons is proportional to their wavelength. When you are looking at a clock, light riflecting from it falls on your eyes and you can see the hands ticking away.. now consider same watch when kept inside a gravity sphere( all planets are gravity sphers but very large in size for our use, force of attraction at the center of this sphere is zero as forces from all the sides cancel each other) light reflected from the watch have to work its way out of the sphere and looses energy, Because of resultant increase in wavelength you see the same incidents(like second hand ticking) for a longer time(just like streched a rubber band which appears longer) and thus appear slower.

Now consider a man sitting inside of such sphere, his heart or any other growth of his is just like a clock and would appear slower to a person outside.Now for the light falling into the sphere, it gains energy and thus its wavelength shrinks and outside world seems faster to the man inside. Apparently he is on his rapid motion along time dimension compared to normal speed of one second per second.

Sounds simple huh? constructing a gravity sphere is something that needs a lot of time and money.... but hey it is not impossible... its just too complex.

For those who think all that above is fictious and foolish... i can only say you remind me of my grandmother when i tried to convince her that there are no real people inside of a t.v... LOL stay glued for time travel to past

10 comments:

distant_dreams said...

hey... your pilot post... good one... Its well written, the ends good, the lengths good (not too long, not too short) and enough info. to clear as a science post... good post...

But! i am afraid you got your physics mixed up.. =)
First of all, light is does not get affected by gravity like that, it doesn't gain or lose energy when traveling through gravity like that.
Gravity warps space-time around it, the amount of warping is dictated by Einstein's equation for general relativity, due to this the space-time gets curved around it. So.. as light has to pass through this curved space, the light takes longer to reach the observer.

Second, if the wavelength increases, it does not result in seeing the same frame for a longer time. Hence, because the wavelength increases does NOT mean the observer sees the same thing for a longer time, hence "perceives" the time to go slower... the light actually does take longer...

This is the same in a black-hole.. the light cannot escape it because the curvature of space-time is infinite, because the mass is infinite at THAT point (which causes the black-hole in the first place..)

distant_dreams said...

But it really is a well-written post, if its edited then its good as it is... :)

yang said...

don think so. try this.. i just said photon works its way out.. you are right that space time arouund the shell is curved for better understanding consider a ring pressed into a flexible rubber sheet you can move freely as long as you are on flat rubber surface inside the ring but if you try to climb out you need a lot of enegry.. same is the case with photon.. on its way out it has to spend its energy against gravity or its wave length becoms longer this is what we call redshift... ever heard of it?

second point when wave length becoms longer consider this.. imagine a bulb switched on only for one wave of light to escape and then switched off.. for our discussion think light has wavelength n=(c/f). now when this same wavelength becoms 2n or 3n and observed you can see the pulse for longer or the duration for which the bulb is on appears longer or the action of switching the bulb on and off appears longer...

i missed out these details with blog size in mind.. will try to be more eleborate from next time..

distant_dreams said...

nope, wrong... red shift is not caused due to that.. thats what i thought too at one time, buts its not cause of that, red-shift is caused when the source of the light is moving away from the observer, then red shift occurs, blue-shift occurs when the source is moving towards the observer. in fact you can check it out here... http://www.physicsforums.com/

About the wavelength, just because the wavelength is longer does not mean we see the frame for longer, if we vary the wavelength, we vary the color of the light..

distant_dreams said...

this is the specific link you should check for redshift...
http://www.physicsforums.com/showthread.php?t=124367&highlight=red-shift
also, theres a wiki, check here...
http://en.wikipedia.org/wiki/Redshift

yang said...

bro.. with no offence please read the links once yourself before you forward them to me.... wiki page just conformed what i wrote.. and about increase in wavelength i magine you are writing a letter on a paper and while sending the font size got increased somehow... then less information is transmitted in same space.. if still confused i will talk to u tomorrow
http://en.wikipedia.org/wiki/Redshift#Gravitational_redshift

distant_dreams said...

dude... didn't mean to sound putting down, was just stating what i thought was right, but i get the concept now, i owe you an apology.. but still, i just don't get how light can be affected by gravity, after all it has no mass, if you could clarify that, i would be grateful.. [:D]

distant_dreams said...

ah yes, checked up, from my wiki link only, Right you were, the point is simple, answering even one of the questions ive had for such a long time, its given by Einsteins energy, mass equivalence, since light has energy, it is affected by gravity in much the same the same way as an object having mass is.. I apologize for my accusation... [:)]

yang said...

never mind bro...

Aparna.G said...

Hmmmmm..

Not going all scientific about it, but, this concept of 'Time Machine' is appealing, but am not too intimidated by it..

Good post.. :-)