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A few questions about relativity

PostPosted: Sat Oct 08, 2011 6:47 am
by Crescent Pulsar R
Yes, this is another one of those "coming from an idiot" topics. (Do note the underline and prepare to facepalm. Perhaps multiple times. You might even have to perform a... c-c-c-c-c-c-combo breaker! Fair warning in case you wish to save yourself a trip to the hospital because of self-inflicted wounds to the face in addition to possible brain trauma.)

From what I understand, less time passes for one thing when it's moving faster than another thing. But is that an illusion? I was wondering because, if we measure something that's traveling significantly faster than we are, and we say that it goes from here to there in a second, isn't it really less than a second? And if we constrain it to our perspective, having more time for us to observe its travel (i.e., if our eyes were high speed cameras, we'd be able to observe a bullet in motion after being shot out of a gun) would render the time it saved moot, wouldn't it? At the very least would averaging the times make more sense?

And there was something else about this that confuses me. I heard that only about six days have passed from the perspective of being at the center of the universe, but that sounds like the opposite of what (little) I understand of relativity.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 7:17 am
by Spokavriel
Time dilation either related to velocity or gravity has been experienced by astronauts, And they even currently have shown its effects with time pieces and the like on the International Space Station.

There is also the Experiment that was done shortly after the sound barrier was broken. Two clocks were made and tested to prove how accurately they keep time. Then one was sent by super sonic jet to California. The difference in times was reported by telephone and radio. Then to double check the second clock was sent by railroad to California and there was indeed a difference because the first clock had apparently traveled fast enough to experience less time than the second time piece. Or something like that. I have to look it up again and I kinda just woke up today.

There is less movement at the center of the Universe. Einstein said the faster you move the more time you experience. His theoretical limit claimed that just before reaching the speed of light the time you experience would be near infinite making speed of light travel impossible. Originally disproved by the discovery of neutrinos. And in the past weeks by that other space observation. However if it is moving towards us along our Universal direction of travel we might just be seeing our cumulative velocity in relation to each other. We aren't on a static point in reality to measure other velocities from after all.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 8:56 am
by Crescent Pulsar R
Yeah, I've heard about the atomic clocks that were used at least in one case (one was in orbit, and I think I heard about it from a show regarding how GPS worked). But it just seems to me that, if the viewer has more time to observe something, based on the distance it travels rather than how long it travels, there's ultimately no difference in time; we can say that light travels at 186,000 miles per second (in a vacuum) because two perspectives turned upon themselves is linear, thus definitive rather than relative. That's how my brain is seeing it at the moment, anyway, so I'm hoping for some enlightenment if I need it (which is likely).

Spokavriel wrote:
There is less movement at the center of the Universe. Einstein said the faster you move the more time you experience. His theoretical limit claimed that just before reaching the speed of light the time you experience would be near infinite making speed of light travel impossible. Originally disproved by the discovery of neutrinos. And in the past weeks by that other space observation.
Speaking of which, I think they recently started to investigate some results at CERN, regarding faster-than-light travel.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 9:09 am
by Spokavriel
Isn't CERN the same lab that has had a super collider going for the last 2 decades? And placed an iron bar in the same room doing a Speed of Light test where they managed to transmit sound faster than light through the solid bar?

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 10:32 am
by Crescent Pulsar R
CERN only recently made the largest particle accelerator to date. I haven't heard of the thing with the metal bar but, then again, I've heard a lot of things that (supposedly) happened there. What I heard, in this case, was that they might have clocked a neutrino that had exceeded the speed of light. I think they're going through the "making sure that's what happened or not" process.

To be honest, I never really understood why there would be a speed limit. More of a gut feeling than a cerebral one.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 10:44 am
by Spokavriel
Even if there is a speed limit. All movement is Relative. Technically Neutrinos going the opposite direction of our planets galactic movement could easy appear to travel our velocity plus its own. That fact seems to be overlooked in all experiments and reported observations so far.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 11:16 am
by Ellen Kuhfeld
Spokavriel wrote: Even if there is a speed limit. All movement is Relative. Technically Neutrinos going the opposite direction of our planets galactic movement could easy appear to travel our velocity plus its own. That fact seems to be overlooked in all experiments and reported observations so far.

Special Relativity doesn't work that way. Even two observers moving towards one another at almost the speed of light (relative to their meeting point) will see each other as approaching at less than the speed of light.

The twin paradox is even worse, and has broken the minds of many relativists. I'd want to bring in General Relativity and start playing with the gravitational effects upon the timeline of the twin in the spacecraft.

If the CERN "faster than light" neutrinos turn out to be truly faster than light, that will throw both theories into a cocked hat.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 11:25 am
by Spokavriel
Doesn't Special Relativity depend on light as the medium for observation to stay true?

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 11:29 am
by Ellen Kuhfeld
Spokavriel wrote: Doesn't Special Relativity depend on light as the medium for observation to stay true?

Not quite -- it depends on electromagnetic radiation (one subset of which is light). And those who study gravity are grudgingly starting to think it travels at the speed of light also. It depends, really, on c being the fastest speed of propagation for information and matter. If something faster shows up, we'll have another paradigm shift to keep everybody busy.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 3:29 pm
by Vocaloid
But that would bring spectral mass, density, and diminutional vibration as well.

Re: A few questions about relativity

PostPosted: Sat Oct 08, 2011 5:15 pm
by Knight of L-sama
Crescent Pulsar R wrote:From what I understand, less time passes for one thing when it's moving faster than another thing. But is that an illusion? I was wondering because, if we measure something that's traveling significantly faster than we are, and we say that it goes from here to there in a second, isn't it really less than a second?


No. It's for real. Its internal clock will have experienced less than a second (how much depending on how fast its going).

Crescent Pulsar R wrote:And if we constrain it to our perspective, having more time for us to observe its travel (i.e., if our eyes were high speed cameras, we'd be able to observe a bullet in motion after being shot out of a gun) would render the time it saved moot, wouldn't it? At the very least would averaging the times make more sense?


What? You can't constrain things to your perspective, whatever that is supposed to mean. That's the thing about relativity. Everything is relative. It's just for every day circumstances its generally convenient to use a reference frame related to the surface of the Earth.

Crescent Pulsar R wrote:And there was something else about this that confuses me. I heard that only about six days have passed from the perspective of being at the center of the universe, but that sounds like the opposite of what (little) I understand of relativity.


I recognise this. Its the bovine excrement shovelled by certain types of creationists and if that's where you're getting your information, its no wonder you're confused. They have a tendency to cherry pick and mangle science to fit their pre-conceived biases. You're better off ignoring them.

For one thing, its clrear that they don't understand relativity since GR specifically states that there is no privileged frame of reference and there's no such thing as the 'centre of the universe'.

Re: A few questions about relativity

PostPosted: Wed Oct 12, 2011 8:01 am
by WG_Writer
The basic traditional implemention thoughts on how GR work is often used using two basic examples, the spaceship accelerating and the black hole: time dialation. With the space ship example using the e=mc2 formula in order to surpass the speed of light regardless of the amount you accellerate, if you are using on board accelleration, then eventually more and more of the mass of the ship will need to be fuel of some sort, eventually as you reach the speed of light you have meet or passed the 100% point of your ship mass being fuel.

This is why in most SciFi works, Star Trek, B5, Star Wars, etc you hear phrases like Sub Space and Hyperspace as ways to go somewhere that this is not true and drive a ship there then revert to "Normal space".

The Black Hole: Time Dialation example states if an observer in a space craft watched someone fly into a black hole they would seem to expand in the direction the the singularity and eventually disappear in "Minutes" where as from the perspective of the one going in it would seem like far more time and they would not think they are expanding, but rather that the universe around them has slowed.

Again most SciFi works show this accelleration by having ships going faster then light stetch out and elong briefly as their engines kick in, Star Trek being the worst offender of this.