Originally Posted by RussT
-Why would you think that the Earth orbit would be modified by the rocket launch? Please answer the direct question.
I don't think Earth's orbit would be affected/effected by any rocket launched at any speed/velocity up to and including 'infinitely fast'....BUT you do....don't you?
I know earth's orbit would not be affected because I simpy understand that you or anyone else cannot *Ignore Gravity* and think that that rocket is either...
1. pulling earth towards the sun faster and faster the faster it travels....OR
2. causing 'space' in front of the rocket to *Disappear* the faster and faster it travels.
Knowing (and this word has even become nearly impossible to use!!!) that the earth's orbit, has remained the same for nearly 4.6 Billion years, whether it is held in place by a Magnetic Field or a gravitational field, is as close to fact as you can get.
If an alien landed on earth, saying he had just traveled nearly "Instantanesously" to the Sun, would you believe him when he said...
Therefore the distance to the Sun MUST be nearly Zero distance?
I doubt that an alien with the technology to be able to travel "nearly "Instantanesously"" would be foolish enough to claim that the distance would be nearly zero.
Sorry, but can you get to the point?
I don't see yet how Russ's rocket proves the distance between ......
You know what i mean.
In my understanding it is an observational fact that the speed of light is a universal constant independent of velocity of source or observer.
are you disputing this?
Tensor's pretty bright. I'd assume that he's aware that it's not really possible to accelerate instantaneously to the speed of light. But his statement gets most of the idea across. A more precise wording might be that if you travel from here to Alpha Centauri, moving at arbitrarily close to the speed of light, the trip will take roughly four years for outside observers, but will be arbitrarily short for the person traveling. Depending on how fast you go, the trip could take a year as measured by the traveler, or a day, or a second, or a nanosecond. Essentially no time as measured by an outside observer, if the traveler is moving quickly enough. And it still scales. If you're traveling fast enough that time dilation means you measure a nanosecond .to go four light years, then it will take you a whole second to travel four billion light years
Originally Posted by RussT
SO, how do they/you justify that light from differing distant sources, even in the frame of the light paths taken, straight line if no massive body curves it, goes from the source to us "Instantaneously"?In other words, the light that is emitted from say Alpha Centauri gets here instantaneously just like the light from a Quasar 13 billion light Yr's away?
So Grey, how have you been able to justify or ignore this?
Because it's not true. There is no valid relativistic reference frame in which light gets from any point to any other point instantaneously. In every valid reference frame, light (when traveling through a vacuum) travels at the same finite speed, and so there will be a measurable amount of time between its emission and absorption.
Originally Posted by EvilEye
But NOT measurable by the photon's perspective. It is instantaneous for the photon.. not for the person measuring it.I still can't get pastthe fact that time stops at the speed of light. And if c is c, then c is c, and for the photon the trip is instant. It has not aged.
I'd disagree, and simply state that the question of how much time passes in the "rest frame of the photon" is not a meaningful one within relativity. In any valid relativistic reference frame, light moves at c, so there's no such thing as the rest frame of a photon. Now, as I said, one can bend relativity a bit, and try to use it to answer the question, "well, what if it were a valid reference frame, how much time would pass?" And it's true that a certain reading of the equations would tell you that no time had passed. But you'd also find that some of the relativistic equations would now include division by zero, so that should be a big clue that you shouldn't take your results too seriously. It's certainly true that there's no way to measure how much time elapses between emission and absorption for a photon, but that's at least as much because there's no way for a clock of any sort to travel along with a photon as because "no time passes".
I will say it one final time: the only "proper time" or "proper distance" that connect the emission and absorption of light are zero. This is an invariant result, which means it is not coordinate dependent, and is true for all observers, including us.
We think it is this much, the spaceship captain thinks it is that much.
You meet a woman. you measure yourself as big she measures you as small.
You think you are young she thinks you are old.
Besides, without special relativity, you end up being a little stuck for explanations for longer-lived intermediate particles in cosmic ray showers.
The "First" thing detected is...the 'energy' 'seems' to disappear nearly instantly!
SO, what does that mean? It simply means that Muons DO NOT exist!!!
Same thing with the LHC...colliding protons together just shows that "Energy is NOT Conserved"...they have "Made UP" Quarks...Quarks and all their 'flavors' and 'coulors' do NOT even exist!
Now, if you want to talk about quarks and flavours and colours, that's a different issue altogether.
Personally, I fantasize that neutrinos are at the bottom of it all
BUT, let's just stick with Gravity.
That spaceship captain is absolutely "Ignoring Gravity" IF he thinks that the distance from the sun to the the Earth is changing At All because of "His Velocity".
AND, this needs more explanation, BUT the spaceship captain CANNOT measure "Distance" as he cannot 'see' "Time" and "Distance" together...A light Year means NOTHING to him....therefore a "Light Second" is also meaningless to him....SR uses "c" BUT that is not the same "c" at 186,282.397 miles per second that our "Eath Rest Frame" observer uses, that sees the sun sending it's light to us in ~8.32 seconds.
"c" in SR is 0 to near infinity. A Singularity!!!
SO, the "Earth Rest Frame" Observer is NOT equal to the "SR" "Rest frame Observer"!!!
And, then you even go to "None Moving" analogies to show your "Blind Faith"
And And And, THEN your next post is "Tired Light" "Nullifying" "Time Dilation"...........hummmmmmmmmmmmmmm
The photometry of SN 1995K extending over about 50 days
provides sufficient data to probe the effect of time dilation on
a clock running at a cosmological distance. We find that
including the time dilation expected from universal expansion
makes SN 1995K comparable to local SN Ia’s and a fair
representative of its class.
On the other hand, assuming a static universe, SN 1995K
had the slowest photometric evolution of all known SN Ia’s
despite appearing spectroscopically indistinguishable from local events
It is even less luminous than the mean of local supernovae and would
constitute a unique and peculiar SN Ia
He doesn't think it is 'changing'. His value for the measured distance is different than ours, that's all.
So accepting that 'c' is the same for all observers as per experiment/observation, If i drive my car at the speed of light in the dark and switch my headlights on, will i see anything?
Time dilation then, is just a contraction of stuff caused by intense velocity of something traveling within it. So, no the distance would not remain the same, but as soon as your vehicle slowed down, the stuff would go back to a more comfortable density and we'd be back at the standard distance.
If the Sun were to suddenly stop emitting photons, would the distance between Earth and Sun increase?
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