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How do you measure time?

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posted on May, 24 2005 @ 10:37 AM
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This almost caused a brain lock, and reboot.

How do you measure time?
By how long it takes to get from point A to point B, relative to how long it takes some other observed action?

If that is right...or if you come up with anohter answer... then answer the following...

If you can jump from one point to another by something like FTL travel or some kind of space warping....

Then wouldnt that also be considered time travel? Because if you bend space...you must bend time...

help!




posted on May, 24 2005 @ 01:10 PM
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Time is distance / velocity.

I wouldn't talk about FTL travel with relativity. 1/sqrt(1-v^2/c^2) ... if v = c, denominator = 0. 1/0 = infinity, so there's no solution to the problem.

So according to Einstein, c is the physical limit.



posted on May, 24 2005 @ 01:12 PM
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I'm sorry if you haven't taken a course in modern physics or relativity and you don't know what I'm talking about with gamma. If you want more just google it.



posted on May, 24 2005 @ 01:21 PM
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So this is the headache Col. Jack O'Neal, on Star Gate SG1, always got whenever Maj. Carter would start talking in technical terms.

Excuse me while I find some extra strength aspirin.

T, could you break it down for those of us who are curious, but graduated "Thanky-Laudy!" from high school?



posted on May, 24 2005 @ 01:45 PM
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Time is generally measured as how long it takes something with constant velocity to travel a constant distance. Unfortunately, since velocity is also relative to time, it is kind of hard to determine one independently of the other. For example, if I'm traveling at 60 mph, then in one hour I travel 60 miles. You could say that one hour is then the time it takes me to travel 60 miles. But if I somehow travel that distance in less (or greater) time, then was it because I started accellerating/decellerating or because the time measured wasn't constant?

Generally speaking, light is used for this measure, and a second is the length of time it takes light to travel 186,000 miles in a vacuum. Of course, this is still an interdependant calculation, because we can also look at it as 186,000 miles is the distance that light travels in one second (in a vacuum.) In fact, if I remember correctly, that's how the figure for the speed of light came to be; it was measured against time, instead of time being measured against it.

Another measure for time, mainly used by atomic clocks, is determining how long it takes an atom to vibrate a given number of times. That is more appropriate in my opinion, but it's still somewhat interdependant. In order to determine the proper number of vibrations in a second, you have to have your stopwatch there and count the number of vibrations that happen in one second.

While T_Jesus is right, mathematically speaking the speed of light is the physical limit on velocity, one thing I always found interesting with relativity is you can use it to disprove that part of the theory. A bit of an explanation of the theory is in order here though.

Relative velocity is measured as one object moves in relation to another. An example Einstein himself used was this: you have two trains moving next to each other on a platform, train A at 15 mph and train B at 20 mph. They're both moving in the same direction. From train A's perspective, train B is pulling ahead at 5 mph. From train B's perspective, train A is moving backwards at 5 mph.

If they're moving in opposite directions at the same speeds (15 and 20), then if you look at one as being stationary, the other is moving away at 35 mph. This is using each train individually as a frame of reference. If you're standing on the platform and using the platform as your reference frame, then each train is moving in it's direction at the speed stated.

The disproving of the speed limitation follows a similar pattern. If I'm on an extremely fast train moving at 60% the speed of light, and there's another one moving away at 60% the speed of light, then in relation to each other we're traveling at 120% the speed of light, obviously faster than the physical limitation.

(I can't remember if that has been disproven or is considered in the theory; if it has, then please forgive me.)

Warping space, in essence, is not FTL travel, because even though you are travelling a technically greater distance from point A to point B, you aren't travelling the space in between. That said, you technically aren't travelling the "time" in between either. (I'm going off of speculation here; no studying or research at all, just my own reasoning as flawed as it may be.) You could argue that it is time travel, because you end up at one location the moment you left the other location.

For example, if you maintain a velocity of 60 mph, and you are planning on travelling a distance of 120 miles, it should take you 2 hours to get there. You start at noon, you arrive at 2 pm. If you manage to bend space enough to elminate a 90 mile stretch in between, you only have a half hour drive. You arrive 90 minutes sooner than you should have. You could reason that you travelled back in time 90 minutes from your original destination. However, it isn't time travel in the sense that you would go back to a point in time before you left per se; don't get any ideas about stopping Oswald (or the CIA, or Mafia, or whomever) by creating a Star Trek-esque warp drive.

Ok, now my head hurts too...I hope this made some kind of sense to someone



posted on May, 24 2005 @ 02:00 PM
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Ok, so if Mickey's big hand is on the 12, and the little hand is on the.....

Jake, I hope these brainiacs cleared it up for you. I gotta go to the store for more aspirin.



posted on May, 24 2005 @ 02:04 PM
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I will read it a few times, and Im not so sure about the c limit. Some things get better with time. Maybe it will make sense tomorrow.



posted on May, 24 2005 @ 02:15 PM
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from jake
How do you measure time?


I got 3:20 p.m.(est)



from Jake
If you can jump from one point to another by something like FTL travel or some kind of space warping....

Then wouldnt that also be considered time travel?


I say no, as Mcory1 broke it down for us 'laymean', your not travelling through space/time. If i can jog a mile in 7mins, i can drive it in 60secs. is that time travel? IF you can bend space/time its not(technically) FTL travel your 'skipping' the space inbetween.

[edit on 24-5-2005 by Rren]

[edit on 24-5-2005 by Rren]



posted on May, 24 2005 @ 02:21 PM
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'skipping' the space inbewteen.


That would be a wormhole, compressing space in front of you and expanding it behind you(like a moving sidewalk) will theoretically allow you to travel FTL. You aren't skipping the space inbetween your making space itself move around you.



posted on May, 24 2005 @ 02:28 PM
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The c limit isn't really that difficult after you break it down a little bit. T_Jesus did a reasonable job of that, but it's kinda hard to explain math on the internet. I'll see what I can do about it here...

In relativity, you have an underlying equation called the gamma factor. The gamma factor is used to describe the various effects extremely high speed has on an object with matter. Without detailing them too much, an object travelling at high speeds experiences an increase in mass, length contraction, and time dilation--time "slows down" when you travel at extremely high speeds. I'll let someone else explain those if needed, or you can search for them online or find a book about relativity. Just about any resource can cover those pretty simply, and much better than I could. Anyways....

As T_Jesus wrote out, the gamma factor is 1 / SquareRoot( 1 - (v^2/c^2)). I'll try and break it down a little bit--if I get too simplistic, don't take offense; I don't know how much you know about math. Starting at the bottom, you have the quantity (v^2 (v, or the velocity of the object, squared) divided by c^2 (c squared).) This is subtracted FROM 1, and the square root is taken of remaining quantity. Then, 1 is divided by what you get after the square root.

The limitation comes in when velocity (v) is equal to the speed of light (when v = c). then you have c^2 / c^2, which gives you 1. If you subtract that from 1, you get 0. The squareroot of 0 is still 0, and then if you divide 1 by zero you get an error on every calculator I've tried it on
There is no numerical result when velocity is the speed of light, or as T_Jesus said, the answer is infinity. Either way, it isn't mathematically possible.

Hope that helped a little, or at least didn't make it worse



posted on May, 24 2005 @ 04:26 PM
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No one has disproved Einstein's theories and the physical limit of the speed of light.

Why doesn't anyone dispute the physical limit of absolute zero around here? It's the same deal.



posted on May, 24 2005 @ 04:59 PM
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Originally posted by T_Jesus
No one has disproved Einstein's theories and the physical limit of the speed of light.


What I meant was whether my disproof had ever been disproven or was given consideration in the original theory. I remember stating it to someone a long time ago, but I don't remember what their response was. There's a part of me that wants to say the speed of light is the limit in reference to a totally stationary object, but from that perspective again, what is the reference frame for it being stationary?



Why doesn't anyone dispute the physical limit of absolute zero around here? It's the same deal.


Because absolute zero isn't as exciting (although it is cooler...
) Nor is it as heartbreaking as having a universal speed limit. Think about it: how many people go out and spend money on a refigerator that's colder than their neighbors'? Conversely, how many people want a car that's the fastest in the city? People like going fast; being cold isn't as fun. Also, being able to surpass the speed of light would allow for much greater flexibility in space travel. Unfortunately though, it does appear that its a limitation we will have to live with. The "disproof" I offered up earlier doesn't change the mathematical facts. One thing that has always stuck in the back of my mind is that barriers have always been broken, it's just a matter of time and technology. For the longest time, the sound barrier was thought to be an absolute, and it's broken on a daily basis by even our lesser jets. Of course, as far as I know there was no math to back up the sound barrier limit, which does give more credence to the light limit.



posted on May, 24 2005 @ 06:26 PM
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Sometimes when I reach into my fridge for a drink, and then take a sip, I wish it were colder. I'm talking absolute zero cold.

Really though, absolute zero has many more cooler implications than a universal speed limit. Mainly because even if we could travel faster than light...we really don't have the technology to do it. Absolute zero though, we get closer to that every day.


Dae

posted on May, 24 2005 @ 06:36 PM
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Originally posted by MCory1
Time is generally measured as how long it takes something with constant velocity to travel a constant distance. Unfortunately, since velocity is also relative to time, it is kind of hard to determine one independently of the other.


Lovely explanation there, thanks, I enjoyed that



posted on May, 24 2005 @ 08:07 PM
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Wait, wait, wait. You are saying if it were possible to travel to venus with the capability of being in two places at once, how would you measure this? This to me is the hard to verify.

Time is almost anything you want it to be. Some people think 'time is money', while others say 'time is on their side'. BTW, does time have to be rythmic?



posted on May, 24 2005 @ 09:08 PM
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I measure time with a clock.

Time is VERY relative. Most people just get a thing that clicks on a regular basis, then count how many clicks it takes for the sun to reach the same hieght in the sky, connect some gears and hands to it and you got a clock.

Just keep the clock where it is and it should be prefectly accurate.



posted on May, 24 2005 @ 09:41 PM
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How do you measure time?


How about love?

Thought someone would've done that by now.



Proving c is the limit comes directly from relativity. If you plug in values of velocity greater than c, you get an imaginary number. Time does not progress in imaginary numbers. Therefore, no faster than light travel.



posted on May, 24 2005 @ 10:40 PM
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Ok, this thread has mentally scarred me as I've thought about it all day long.

Remember the two clocks, set at the same, precise time, they placed one on the space shuttle and left one on the ground. When the shuttle returned, the one that was in the shuttle was a bit slower than the one that remained on earth. Consequently, it was pointed out in the article that if one twin went up and one remained on earth, the one that went up would be younger upon return as time slowed down for him.

Argh! Where's the aspirin?



posted on May, 24 2005 @ 10:46 PM
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I bet if you had a modern physics class it wouldn't seem that difficult. In my class, I thought relativity was the easiest part.

It's not intuitive, but with a halfway decent professor, it won't seem too bad. All you need to do is understand the equations and the meaning of what they spit out.



posted on May, 24 2005 @ 10:57 PM
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Originally posted by T_Jesus
No one has disproved Einstein's theories and the physical limit of the speed of light.

Why doesn't anyone dispute the physical limit of absolute zero around here? It's the same deal.


I have read of a theoretical particle called a tachyon that supposedly travels beyond light speed. Does anyone know if these tachyons are generally accepted as existing and exceeding lightspeed? Also, regarding the two clocks that differed, what was the reason time slowed down for the one that went up in the shuttle?
And if an increase in speed makes time slow down, then would not a full stopping of motion, ie: absolute zero, where the lightest element, Hydrogen becomes a solid, would that make time speed up, or since nothing is moving, would it mean that time no longer existed? I always viewed absolute zero as being timeless, since if nothing is moving, then a nanosecond and a millenium would be indistinguishable. Right?
Okay, who has the aspirin?



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