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Appearence of traveling at superluminal velocity

 
 
maxdancona
 
  1  
Reply Tue 9 Jul, 2013 12:18 pm
@dalehileman,
Quote:
you might conclude you're (they're) traveling at a speed many times c


This is incorrect. You will never "conclude" (observe) that anything is traveling faster than c relative to you.
dalehileman
 
  0  
Reply Tue 9 Jul, 2013 01:08 pm
@maxdancona,
Quote:
you might conclude you're (they're) traveling at a speed many times c

Quote:
This is incorrect. You will never "conclude" (observe) that anything is traveling faster than c relative to you.
Sorry Max if I wasn't clear. If you reread my posting #……261 you will see, "If you're not familiar with the principles of Relativity, you might disbelieve your instruments:"

Of course in real life you understand Einstein and believe your instruments, which set the limit at c, but the difference in clock readings would seem to say you're going many times faster than that
maxdancona
 
  0  
Reply Tue 9 Jul, 2013 01:38 pm
@dalehileman,
Difference in what clock readings?

Relative to you, you aren't moving. There are no observations you could make that would lead you to believe that you are moving-- because you aren't.

You will never conclude based on any reading that anyone is traveling faster than c relative to you-- because they aren't.
maxdancona
 
  0  
Reply Tue 9 Jul, 2013 01:41 pm
@dalehileman,
Let's try this... and remember that any statement about speed needs to specify a frame of reference (because we are talking about relativity)-- so if you say something is motionless you need to specify motionless relative to what, and if you say it is moving at near light speed you need to say it is moving near light speed relative to what.

Let's start with this as a given.

1. Relative to you, you aren't moving (I think this is a safe bet).

Now give me a hypothetical where you think that something will appear to be moving faster than the speed of light relative to you (by seeing clocks, or any other measurement you could make).

(Answer: Einstein says that nothing will ever move faster, or appear to move faster in any way, than the speed of light relative to you.)
0 Replies
 
izzythepush
 
  0  
Reply Tue 9 Jul, 2013 02:13 pm
@mrpjspencer,
mrpjspencer wrote:

Well from what I understand the closer you get to the speed of light,


You can't get close to the speed of light, every time you try to creep up on it, it fucks off sharpish.
0 Replies
 
dalehileman
 
  0  
Reply Tue 9 Jul, 2013 02:15 pm
@maxdancona,
Quote:
Difference in what clock readings?
Sorry again if I wasn't entirely clear. The readings described in my posting #….261. For instance when you're passing Mars you note that Marty's clock reads 5 minutes later than yours

Quote:
Relative to you, you aren't moving.
Yes, yes, I do understand about relativity. Again, I'm assuming an observer who doesn't. When he passes Mars, noting the reading on Marty's clock 5 minutes ahead of his for instance, if a relativist he assumes a relative velocity near c, if he isn't, then many times faster than c, etcetera ad infinitum

Which brings up an interesting q. If he doesn't then fire his retros to come back home, in just a few moments shouldn't he "traverse" the Universe, upon his return (from the other direction?) finding a diminished sun, Earth lifeless, having since gone cold

..which would suggest it was he who was moving and not the rest of the Universe. However we know better of course, that he's entitled to think that after taking off he became stationary and it was all that matter moving through it past him……..

…….still kind of troubling somehow

……though I believe I might be misunderstanding your viewpoint. Watching out the window of the rocketship of course it looks to you like the rest of the Universe rushing past at c but no faster since of course since the distances have diminished since you took off

But again remember I'm assuming a traveler not familiar with Einstein

OT but wondering incidentally if you were in on a much earlier discussion in which I referred to a sort of "relative relativity" to better explain foreshortening, clock slowing, etc
maxdancona
 
  0  
Reply Tue 9 Jul, 2013 02:34 pm
@dalehileman,
Quote:
Yes, yes, I do understand about relativity. Again, I'm assuming an observer who doesn't. When he passes Mars, noting the reading on Marty's clock 5 minutes ahead of his for instance, if a relativist he assumes a relative velocity near c, if he isn't, then many times faster than c, etcetera ad infinitum


No you don't understand about relativity. this doesn't make sense (in any frame of reference). The measurements made by an observer has nothing to do with whether the observer understands relativity or not.

Any observer is motionless relative to himself (and if he is seated in a spaceship will be motionless relative to the spaceship), and every measurement any observer makes would prove he is motionless relative to himself.

What you are saying really doesn't make sense.

dalehileman
 
  0  
Reply Tue 9 Jul, 2013 03:53 pm
@maxdancona,
Quote:
No you don't understand about relativity.
Some aspects do escape me though I think I understand the basics

Quote:
this doesn't make sense (in any frame of reference). The measurements made by an observer has nothing to do with whether the observer understands relativity or not.
Of course not. But not understanding Relativity he might interpret the results of his measurements differently than someone who does. For instance if he leaves at noon and reaches Mars when his own clock reads 12:01, then not realizing that his acceleration had brought the planet closer he might conclude that his speed was 5c

Quote:
Any observer is motionless relative to himself
Forgive me Max but Not sure just what you mean by that

Quote:
(and if he is seated in a spaceship will be motionless relative to the spaceship),
Yes I guess that's pretty obvious


Quote:
and every measurement any observer makes would prove he is motionless relative to himself.
I suppose so but I can't see how anyone would go about making such a measurement
Quote:
What you are saying really doesn't make sense.
. Clearly we have a semantic impasse of some sort though, alas, I think the others have given up on us
0 Replies
 
mark noble
 
  0  
Reply Tue 9 Jul, 2013 04:35 pm
No matter how fast you travel - your clock will tick at the same rate.
You needn't apply 99% c, you only need a train to experience this frikkin obvious event.
If you are looking out a moving train's window, objects outside will appear to be passing by at a faster rate than if you were observing them whilst jogging.
It is YOU who is moving faster, not time slowing down - your watch will tick away the same rate in both scenarios.
It doesn't matter how fast the train travels - Result is the same.
You could travel at c X 1,000,000,000 - result the same.

Time is an artificial measurement, relative ONLY to the observer And ONLY from within the dimension it is observed from.

An inch, to me, is 20 feet to an ant - I could tell the ant it is an inch, and the ant might well relate to it as such, thereafter, but its concept of that inch will be far removed from mine.
dalehileman
 
  0  
Reply Wed 10 Jul, 2013 10:42 am
@mark noble,
Quote:
No matter how fast you travel - your clock will tick at the same rate.
Yes, that is to you, the "traveler"


Quote:
You needn't apply 99% c, you only need a train to experience this frikkin obvious event.
To confirm your observation however the train would have to travel pretty fast

Quote:
If you are looking out a moving train's window, objects outside will appear to be passing by at a faster rate than if you were observing them whilst jogging.
Yes Mark of course much faster. Your observations will however record two apparently contradictory phenomena (that is, if you're unfamiliar with Einstein) as I was discussing with Max: On the one hand your on-board instruments indicate a relative velocity of, say, just under c. But reading the respective clocks (which had somehow all been synchronized before your takeoff) in passing from one planet to the next might lead you to reject the reading of your instruments and instead conclude you were traveling many times c


Quote:
It is YOU who is moving faster, not time slowing down - your watch will tick away the same rate in both scenarios.
Yes that's true in either scenario, whether you consider the planet stationary or your ship. Of course to you Marty's clock seems stopped while to him it's yours that seems stopped

Quote:
It doesn't matter how fast the train travels - Result is the same.
You could travel at c X 1,000,000,000 - result the same.
That's the theory anyhow

….and thanks for chiming in. Maybe you could shed some light on Max's objections to my earlier postings
mark noble
 
  0  
Reply Wed 10 Jul, 2013 04:51 pm
@dalehileman,
I cannot understand MAX, Dale, he types in jibberish.
He mentions 'motionless' states as if they exist (They don't).

Everything is in a state of motion, if any thing were not, then nothing would exist........

we may appear still, when dead, but we are travelling at 1k mph (orbitally) 66k mph (solarly) and immensely faster galactically - Not even considering local-universally and beyond.

weird thing is, we are travelling many times c, and don't even have the ability to measure it...... physically.

dalehileman
 
  0  
Reply Wed 10 Jul, 2013 06:40 pm
@mark noble,
Quote:
weird thing is, we are travelling many times c,….
Thanks Mark but you'll have to elaborate on that one
mark noble
 
  0  
Reply Wed 10 Jul, 2013 07:00 pm
@dalehileman,
Ok...
Imagine an atomic explosion - The inner of which contains a 'near' vacuum - Time here is virtually suspended - Anything developed within this realm is ignorant of all external processes - Billions of years can pass, trillions even, before that vacuumised realm destabilises and rejoins this realm.

To us ( beyond the vacuum ) mere moments have passed.

Anything within that realm that evolves an understanding of the physics involved will only be able to perceive it 'Relatively'.

As we do... our universe.
oralloy
 
  0  
Reply Sat 13 Jul, 2013 12:24 am
@maxdancona,
maxdancona wrote:
Oralloy, there is no absolute frame of refernce. You are confusing the word "inertial" with the term "absolute". It doesn't work that way.

No confusion. Perspectives that engage in acceleration will have time slow down for them compared to perspectives that remain in their original inertial frame of reference.


maxdancona wrote:
In one frame of reference, right now, you are moving at 99% of the speed of light. In another frame of reference, right now, you are not moving. They are both equally valid.

Your use of the "inertial frame of reference" complicates the picture because it brings in acceleration/deceleration. But it doesn't change the fact that each perspective is equally valid.

Maybe valid, but not exactly equal. A perspective that accelerates will always have the passage of time slow down compared to one that remains in its original inertial frame of reference.


maxdancona wrote:
In the case you suggest one person observes that you started at rest and then accelerated to "near light speed". However, don't forget, that there will be another frame of reference where an observer would observe that you started at "near light speed" and then decelerated to zero.

Even considering acceleration (and inertial frames) it is still equally valid to say you are, right now, moving at 99% of the speed of light-- and that you are moving at 0% of the speed of light. Right now, both of these are valid (in equally valid frames of reference).

While you are accelerating, you will experience the acceleration. However accelerating from rest, or decelerating from a fast speed to rest, are indistinguishable (since they are two ways of experiencing the same phenomenon from different points of view).

This does not invalidate my answer to mrpjspencer that distance will compress and prevent anything from ever exceeding the speed of light.


maxdancona wrote:
Once you stop accelerating, there are still multiple frames of equally valid frames of reference-- in one of them you are going 99% of the speed of light, and the other you are motionless.

It doesn't matter. Once that perspective accelerates, the passage of time is going to be slower for it. They can stop accelerating and put their spaceship on cruise control for awhile if they like, but when they get back home they are still going to find themselves catapulted into the distant future.

And the longer they spend "coasting on cruise control" before they turn around and come back home, the farther into the future they will be catapulted.
dalehileman
 
  1  
Reply Sat 13 Jul, 2013 10:54 am
@oralloy,
Quote:
And the longer they spend "coasting on cruise control" before they turn around and come back home, the farther into the future they will be catapulted.
That's supposedly the way it works, while the notion of "time at a distance" has always fascinated some of us

For instance, assuming we have most remarkable ships capable of instant acceleration to a velocity approaching c, which we can somehow withstand: Supposedly at 11:55 our time Marty had taken off to come visit Earth, comes into view and waves at us in preparation to fire his retros for a visit. At the same instant I take off for Mars

Most intriguing is the idea that the instant I fire my rocket Mars Marty's planet suddenly jumps 5 light years to come into contact with Earth, just as to Marty, we had jumped 5 light years to meet his ship

Now here we are at that instant, by your view at the same spot in the Universe. You maintain that it's noon on Mars, while Marty says "No it's still 11:55 back there," while I assert, "You're both wrong, "It's now 12:05 there"
0 Replies
 
dalehileman
 
  0  
Reply Sat 13 Jul, 2013 11:33 am
@mark noble,
Quote:
Imagine an atomic explosion - The inner of which contains a 'near' vacuum -
Mark you're 'way ahead of me here. At that instant I'd suppose a very dense collection of matter at its very center

Quote:
Time here is virtually suspended - ….ignorant of all external processes - Billions of years can pass…..before that…...rejoins this realm…….To us…...mere moments have passed.
I presume you refer to the area of increased density as equivalent to a strong gravitational field which of course would slow any clock able to withstand the forces and temperatures involved; but I couldn't even guess at its magnitude

As to the term "vacuum," I'm again left in a sort of void (forgive pun) because I'd imagine the condition of the ball at that instant to be the very opposite of a vacuum. Maybe you're using the term in a sort of figurative or expository way that you'll soon clarify

Quote:
…...'Relatively'…...As we do... our universe.
Slightly OT but suggests the phenom might not qualify as "relative" in the exact Einsteinian sense. While uniform motion certainly does, I wonder about the effect of grav, whether it causes a merely relative "slowing" or better described as absolute

Just speculating, I'm 'way outside my area of immediate confidence
mark noble
 
  -1  
Reply Tue 23 Jul, 2013 05:09 pm
@dalehileman,
Sorry Dale, is as clear as day to me.
dalehileman
 
  0  
Reply Thu 25 Jul, 2013 12:15 pm
@mark noble,
Quote:
Sorry Dale, is as clear as day to me.
Alas Mark my apologies at 82 still living in the distant past

Maybe however we could have someone else translate into old-time language, common words arranged logically in short sentences suitable to the Average Clod (me)
mark noble
 
  0  
Reply Sat 27 Jul, 2013 06:54 pm
@dalehileman,
Old-time language?
Latin/Greek/Sumerian?
0 Replies
 
gungasnake
 
  1  
Reply Sat 27 Jul, 2013 07:07 pm
@mrpjspencer,
Hint.....

That little club comprised of authors of dead theories from past centuries: Chuck Darwin isn't the only member of that club; Albert Einstein is a member also.
0 Replies
 
 

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