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This post has been edited by marsalee: Nov 13 2010, 08:10 PM

and what, pray tell, will you call the passing of one moment to the next?

the problem is simple: it's all relative.

rule: the closer u move to the speed of light, the slower time passes for u.

u wont notice time moving faster or slower until u compare it with something that moves slower than u. lets say u have a twin brother, and he stayed behind on earth while u go traveling near the speed of light. when u return lets say 10 years later earth time, he would've aged 10 years (obviously), but u would have aged perhaps only 5 years (depending on how close u were to the speed of light).

but if everybody is moving at the speed of light, then there's no difference in age. u will still perceive time just as u are right now.

Strange.

Why do you compare speed of life with age?

"lets say u have a twin brother, and he stayed behind on earth while u go traveling near the speed of light. when u return lets say 10 years later earth time, he would've aged 10 years (obviously), but u would have aged perhaps only 5 years (depending on how close u were to the speed of light)."

i dont understand this statement. Let say If i travel the speed of light. It only take me to certain place(A) much faster that the light. But the time I travel to A will determine my age, not the speed of light.

For example: If i travel to sun in 1 minute. Earth can only see after 3-4 minutes. By that time, I'm already back to Earth. What earth saw was my past (2 minute ago) but present I'm still 3minute older (when earth see me).

Am I right or wrong?

This post has been edited by 100n: Dec 21 2009, 05:27 PM

[X] wrong knowledge

1. theory of relativity state that the closer you are to speed of light, the slower your "time" is relatively. IE. if you travel for 10 minutes at speed close to c, then stop, 10 minutes of your time has passed. however, 10 years may have passed for someone at a slower speed.

2. your example makes you to be traveling at speed higher than c, (you round trip earth-sun in 2 minute, when light takes 4 minutes - actually around 8 would be closer) which is at current theory, impossible.

I still dont understant this statement:

1. theory of relativity state that the closer you are to speed of light, the slower your "time" is relatively. IE. if you travel for 10 minutes at speed close to c, then stop, 10 minutes of your time has passed. however, 10 years may have passed for someone at a slower speed.

You mean like this example?

If you got in a rocket ship and accelerated you could go what seems infinitely fast to you. You could travel to a star 100 light years away and get they by lunch, turn around, and get back to Earth the same day. But you will find that everyone else is 200 years (and one day) older than you are. From their perspective, you were traveling very close to the speed of light and it take 200 years for light to get to that star and back. But to you, it was only a day. Your aging slowed down because you move forward through time faster. What you observe as linear acceleration in space that obeys Newton's laws, isn't what really happens. You start out accelerating in space but as you gain speed you start accelerating through time instead. You can only move at the speed of light in space, but can move infinitely fast through time.

This post has been edited by 100n: Dec 21 2009, 06:04 PM

I think lin00b is saying that, if you move close to the speed of light, even though you may perceive that your time passes like normal, those who are not traveling at your speed experience the time to be much longer. One minute for you while traveling close to the speed of light is equivalent to 1 year for those who are traveling through time at the regular speed.

Thats what I understand from lin00bs example.

This post has been edited by Mesosmagnet: Dec 21 2009, 06:13 PM

You'll be dead by then.

The impact that happens on that can nv be sustain by a normal human being.

Only immortals can do that probably. I guess u'll have to refer to some of the living beings in asylum/nuthouse to get that question answered.

no, you cannot travel faster than light. so if you do want to go to someplace 100 light years away, it will never be faster than 100 years to you. and to the observer at earth, a far longer time has passed.

your aging does not slow down. you'll still age 100 years. but your 100 years is a lot longer than the observer's 100 years.

what mesomagnet says.

Remember the phrase "Never say never".

Who sez you can never travel at the speed of light or even faster than that? There are still many scientific unknowns in this universe that will (hopefully) be uncovered in the future.

True that at the moment you can't travel at the speed of light because based on CURRENT scientific knowledge, you'll be squashed at the back of your nice spaceship wall if you go "lightspeed" in an instant. However, that's based on CURRENT scientific knowledge. What if somebody uncovered a way to warp space, fold space, enter subspace, enter wormhole, abolish inertia or what not, where mass would not be a factor? Never say never.

The world was once believed to be squared (where if you travel far enough, you'll drop off the face of the earth!) but finally realized to be rounded.
The world was once the centre of the galaxy where everything revolves around it until somebody proved otherwise.
Humans never thought they could fly until the Wright brothers did it.
Newton & Einstein (to name a few) discovered many remarkable things that humans thought not possible.

The sky is the limit. Just that to travel at the speed of light won't probably be in my in lifetime....

Note : Yeah, I see too much movies, read too much sci-fi books and play too many games......

I believe watching more sci-fi could probably uncover the possibilities towards the impossibilities.Perhaps one day , u might even stumble onto some secret sites from googling that provide findings upon using fingers wars to warp into the 8th dimension XD.

So far my brain or my knowledge towards the unknown scientific realms is limited XD. I hope that in my life, someone could uncover how to travel in the speed of light. So that the dude on a bike could not write me a speeding ticket on the highway.

mesosmagnet and lin00b have explained my argument.

the issue brought forward by TS spawned off from the theory of the younger twin brother. but actually it's just a confusion. the twin brother does not "get younger" than the other one. he just experiences time much slower.

it doesnt mean if u travel faster than light, u'll reverse aging .

[X] wrong concept

1. "squashing" is due to acceleration, not velocity

2. warping/ folding/ hyper-space/ wormhole/ whatever sci-fi tech does not break lightspeed barrier even though it may allow you to go 100 light year away in 1 day. its a different concept.

3. and you are looking at this in a different context. the discussion is based on current scientific laws and theories; and current theory puts a boundary at light speed and have some explanation of what happens then. if you want to bring sci-fi and "never know the future" into this, this is probably not the correct forum for you.

This post has been edited by lin00b: Dec 21 2009, 08:36 PM

[?] ??

1. Going from zero to lightspeed is not acceleration? Then what is it called? Velocity?

2. Lightspeed just mean 300k km/s. Does it mean that you can only call it lightspeed if you use conventional rockets and not some other way? If somebody can travel more than 300k km/s using some other method, it is not breaking the lightspeed barrier? Or is lightspeed barrier just solely reserved for the theory of relativity?

3) Yes, current scientific laws and theories puts a boundary at light speed. I did state that fact "CURRENT scientific knowledge". I guess it also includes current rocket technology and not "never know the future" propulsion technology. If that is the case, why discuss about the speed of light when a rocket can only go a fraction of the speed of light? If you want to say "IF you can travel at near the speed of light", that is about the future, no? Based on current technology, it is an impossible "if".

What I'm saying is, there are probably some unknown theories in the future that either improve or disprove this theory, enabling a work around to the lightspeed barrier.

Better get back to my sci-fi games.......

[exit forum]

This post has been edited by kmarc: Dec 21 2009, 09:32 PM

1. discussion is on what happens when you travel at/near light speed. not accelerating to light speed.

2. yes, traveling at a rate of 300km/s; all the other sci-fi stuff deals with creating a shorter pathway to get from point A to point B. but whether you travel at traditional path, or at shortcut you still cant exceed 300km/s.

ie. you travel at trunk road from perlis to jb vs you travel by PLUS. you may reach faster by PLUS, but your car maximum velocity stay the same.

3. rocket is current implementation limitation, current theoretical limitation is light speed, and we are discussing what happens at/near that speed. FTL is currently theoretically impossible, therefore not in discussion.

future theory may/may not be FTL, but in the context of this discussion, it is irrelevant.

2. the time dilation effect (as discussed in this thread) only occurs when u go through conventional means - accelerating from zero to lightspeed or beyond. space fold, jump, teleportation, wormhole etc is faster than light, but it doesnt involve acceleration. hence time dilation wont occur in such situations. it doesnt even break the lightspeed barrier.

but a different time perception does occur. lets say ur departure from earth was celebrated by fireworks. u use a gateway to travel to another point 10 light years away. the journey took 1 day. at ur destination, u look up earth using a telescope, but only sees the earth 10 years ago. for u to see ur own fireworks celebrating ur departure, u gotta wait another 10 years.

this is not time travel.

1. I was replying to your quote "Squashing is due to acceleration, not velocity". I meant that you get squashed if you go for zero to lightspeed, not get squashed when you travel at a constant speed.

2. (For discussion sake) Not all sci-fi stuff deals with creating a shorter pathway from A to B. Hypothetically, if you could create a bubble where only your ship and it's surrounding space is confined, you could move at light speed AND be seen to move at 300k km/s. However, you and the space around you are still stationary in one place while the bubble is moving at light speed. Of course, this is hypothetical and sci-fi.

3. I was just responding to your answers of my "wrong" concepts. FTL is currently theoretically impossible and therefore not in discussion but so is speeding along at/near that speed.

Corrections:

kmarc

You appear to be shorter in length if you move at some constant velocity relative to an observer


Moving close to the speed of light relative to some observer is not theoretically impossible. FTL currently is theoretically impossible

azarimy:

Not really; to make this clear, we label the twin brothers [1] and [2], [1] being the 'stationary' observer, and [2] being the person on the rocket flying off at some velocity

To [1], time goes by slower for [2]. But here's the important point, if [2] looked at [1], he would also see that time goes by slower for [1]. It's purely symmetrical because they're moving at the same velocity (well, excepting the +/-) relative to each other.

This post has been edited by bgeh: Dec 21 2009, 10:34 PM

No, what i meant is that if you accelerate from zero to lightspeed in say 1 second, the acceleration will squash you on the back wall of your spaceship.

"Moving close to the speed of light relative to some observer is not theoretically impossible. Faster-than-light travel currently is theoretically impossible"

Really?
http://www.bis-spaceflight.com/sitesia.asp...ge/1539/l/en-gb

To them, it is also not theoretically impossible.....

This post has been edited by kmarc: Dec 21 2009, 10:51 PM

That's general relativity, and something that I'm not qualified to discuss, but it seems that they're discussing a method to 'increase the speed of light' in some region of space by introducing a new metric (a perfectly fine thing to do)

Yes, but that's irrelevant. You still appear squashed if you move at a constant speed relative to an observer in special relativity.

Here, let's introduce stranger metrics in General Relativity: Godel metric
http://en.wikipedia.org/wiki/G%C3%B6del_metric

Travelling backwards in time using this metric isn't a problem at all; in fact time is probably an ill defined concept using this metric. The important point is to realise whether this metric is suitable to describe our Universe, and while I don't know enough about GR, I'd suspect the same applies to the link you posted.