# Time and perpetual motion

robj101
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Time and perpetual motion

If you see the top spinning, do you assume it had a spinner?

I would if the top looked like it was going to stop. I would assume someone had to start it. If however the top appeared to be in a perpetual spin I might assume it was always that that way.

Every single thing is in motion, down to atoms, sub atomic particles etc, with no sign of stopping. This is how I have looked at time as the measurement of motion for along time (heh).

People consider time as an actual passing of something, I consider it to be simply measuring movement. Time is not "passing" it is a measurement of the movement of things which causes change, perpetually.

Current definitions of time:

1. A nonspatial continuum in which events occur in apparently irreversible succession from the past through the present to the future.
2. An interval separating two points on this continuum; a duration: a long time since the last war; passed the time reading.
3. A number, as of years, days, or minutes, representing such an interval: ran the course in a time just under four minutes.
4. A similar number representing a specific point on this continuum, reckoned in hours and minutes: checked her watch and recorded the time, 6:17 a.m.
5. A system by which such intervals are measured or such numbers are reckoned: solar time.

• If I am correct then time travel and the whole idea is unrealistic and a farce. Is there actual evidence that I am wrong?

The only way "time travel" would be possible would be to set the movement of something to go backwards to a former "state". But this would not actually put you back in an earlier "time" as we see it, it would just be reversing aging by moving things back to said previous state.

Does this even make sense to anyone mor am I alone here.

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

robj101
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As a side note, if my theory is correct, then eternity is a fact. There will be no end of time, as jesus said he would be with us untill the end of time.

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

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I am not at all educated

I am not at all educated enough in physics to make a serious comment other than to say, I believe you might be on to something. I have always been completely confused by the concept of time. But there seems to be something else that does not work. Isn't time supposed to stop at the speed of light? Isn't this General Relativity and aren't we fairly certain of this?

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

robj101
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I am not at all educated enough in physics to make a serious comment other than to say, I believe you might be on to something. I have always been completely confused by the concept of time. But there seems to be something else that does not work. Isn't time supposed to stop at the speed of light? Isn't this General Relativity and aren't we fairly certain of this?

I'm no scientist either, but if something is travelling at the speed of light and time must sit still for it, then that would simply be the cessation of motion. That sounds ignorant because obviously it is travelling at the speed of light. I have not put in much thought on that end of it, the how's and why's. However it would make a strange kind of sense if you considered things have a limit on motion, it is already at that limit with lightspeed so motion within it'self would cease? I would have to think on it. Perhaps what it is moving through takes precadence? again, I'll think on it. Maybe someone else has an idea.

Einstein said nothing can exceed the speed of light, so that could mean motion in general has a limit.

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

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@Rob:  No, you are right.

@Rob:  No, you are right.  The idea behind time travel is usually based on the idea that time is some sort of 'thing' that can be manipulated, but it isn't a 'thing' and it cannot be manipulated, at least not outside of a magical way of reversing every action and reaction of the universe down to a quantum level.

Slowing or speeding up time by changing the speed of an object is something you can do, but it certainly isn't what anyone traditionally means when they say time travel.

Everything makes more sense now that I've stopped believing.

BobSpence
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A key implication of

A key implication of Einstein's theories is that there is no common, absolute Time for points separated by any finite amount of space. The further apart they are, the greater the possible 'discrepancy' that can exist between estimates of the relative timing of events occurring at each point, as judged from either position, or by a third party moving at a different velocity.

The rate at which we will see time passing at another location, as compared to what we observe in our frame of reference, depends on the relative velocity of ourselves and whatever we are observing at the other location, and the strength of the gravitational field at each location.

If two observers at the same point in space, travelling at the same velocity, synchronise clocks, and then separate and travel on different paths before coming back together, their clocks will no longer necessarily be in sync. The one having experienced more acceleration (which, unlike velocity, is NOT purely relative) and/or higher gravitation fields, will have slipped behind the other.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me

From the sublime to the ridiculous: Science -> Philosophy -> Theology

robj101
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Well I watched a Hawking

Well I watched a Hawking special about time travel, and it sounds as if he believes we could possibly travel into the "future" and he makes it sound like the "traditional" time travel theory. His arguement for no travelling into the past involes paradox, which is not even a possibility. I also think travelling forward in this sense would be paradoxical. Suppose one man travelled forward, visits a grand city and then the grandparent of the guy that was going to plan it travelled forward. Another paradox. But according to Hawking forward time travel could be possible.

I like Hawking but I thought he was a bit off on all that, and to question someone of his caliber seems ridiculous but.. HI!

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

robj101
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BobSpence1 wrote:A key

BobSpence1 wrote:

A key implication of Einstein's theories is that there is no common, absolute Time for points separated by any finite amount of space. The further apart they are, the greater the possible 'discrepancy' that can exist between estimates of the relative timing of events occurring at each point, as judged from either position, or by a third party moving at a different velocity.

The rate at which we will see time passing at another location, as compared to what we observe in our frame of reference, depends on the relative velocity of ourselves and whatever we are observing at the other location, and the strength of the gravitational field at each location.

If two observers at the same point in space, travelling at the same velocity, synchronise clocks, and then separate and travel on different paths before coming back together, their clocks will no longer necessarily be in sync. The one having experienced more acceleration (which, unlike velocity, is NOT purely relative) and/or higher gravitation fields, will have slipped behind the other.

I agree, motion is slowed near a pyramid for example, as seen in Hawkings video. A negligible amount but slower nonetheless. But when you say this people tend to think time* is a force of it's own, when actually it is only the ruler we use to measure the motion of things. It might be better said as "motion is slower near a large mass or an area with more gravity."

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

RatDog
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(No subject)

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I get it. Still a mind

I get it. Still a mind fuck. I get completely thought tied thinking about time. The thing that fucks my head as well is the idea that time and space did not exist before the big bang. The three dimensions did not exist? Really?

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

BobSpence
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I get it. Still a mind fuck. I get completely thought tied thinking about time. The thing that fucks my head as well is the idea that time and space did not exist before the big bang. The three dimensions did not exist? Really?

Not necessarily, if the Big Bang occurred within some 'greater' multiverse, probably with up to 11 dimensions, from some theories.

A true 'singularity' has no dimensions within itself. It still may have had some space-time location in a 'metaverse', if it was not the actual 'beginning' of everything.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me

From the sublime to the ridiculous: Science -> Philosophy -> Theology

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RatDog wrote: That....might

RatDog wrote:

That....might be the first time I've actually understood that crap.  Many thanks!

I started the quantum stuff too, hopefully it will be as illuminating.

Everything makes more sense now that I've stopped believing.

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I'll stick to biology and

I'll stick to biology and other things that work on my plane of existence. This thread has helped me a bit though. Many thanks.

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

NoMoreCrazyPeople
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Something that I've never

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

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Right. Doesn't even have to

Right. Doesn't even have to be deep space. As in the video, if you simply orbit the earth at the speed of light, your "clock" slows. Do this for long enough and when you land, all your loved ones will be old and grey while you remain young.

So the OP concept is backward in assuming that distance traveled = more time. The orbiting ship travels more distance but time slows for it.

*Places pistol to temple and cocks hammer*

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

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Really, I just have trouble

Really, I just have trouble reconciling the episode of Duck Tales where Huey, Duey and Louie have a pocket watch that stops time. When they moved that fast, everyone else's time stops, it doesn't go faster. But in H G Wells' story, everyone goes fast and the traveler's time stops.

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

RatDog
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NoMoreCrazyPeople

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

What you are talking about is called the twin paradox.  I don't really understand it very well (or maybe at all), but there is a wiki article about it.

Wiki wrote:

In physics, the twin paradox is a thought experiment in special relativity, in which a twin makes a journey into space in a high-speed rocket and returns home to find he has aged less than his identical twin who stayed on Earth. This result appears puzzling because each twin sees the other twin as traveling, and so, according to the theory of special relativity, paradoxically each should find the other to have aged more slowly. How the seeming contradiction is resolved, and how the absolute effect (one twin really aging less) can result from a relative motion, can be explained within the standard framework of special relativity. The effect has been verified experimentally using precise measurements of clocks flown in airplanes.

Wiki wrote:

Special relativity does not claim that all observers are equivalent, only that all observers at rest in inertial reference frames are equivalent. But the space ship jumps frames (accelerates) when it performs a U-turn. In contrast, the twin who stays home remains in the same inertial frame for the whole duration of his brother's flight. No accelerating or decelerating forces apply to the homebound twin.

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Maybe this is a simple

Maybe this is a simple explanation as to why exercise keeps you younger? Simply moving around more slows your clock in contrast with a person with less inertia.

A daughter of hope and fear, religion explains to Ignorance the nature of the unknowable. -Ambrose Bierce

BobSpence
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NoMoreCrazyPeople

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me

From the sublime to the ridiculous: Science -> Philosophy -> Theology

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gene 203

Really, I just have trouble reconciling the episode of Duck Tales where Huey, Duey and Louie have a pocket watch that stops time. When they moved that fast, everyone else's time stops, it doesn't go faster. But in H G Wells' story, everyone goes fast and the traveler's time stops.

OK, you do realize that you have to abandon the physics of duck tails if you expect to get a good grasp on the concepts in this thread, right? Ditto any other fictional world where physics takes a back seat to telling a story. Star Wars comes to mind here. Let's all head off to Tattoiene for the weekend. When we get there, we will not have to worry about inconvenient things like time dilation and what not. Sure, it tells a good story but the dramatic plot device is a physics hand wave.

Let me try this another way. What would you call common sense? Something along the lines of that which agrees with everyday observations of how stuff happens is close enough to make the point that I am going for.

So if you and I are standing at opposite ends of a stadium, you look very small to me and I look very small to you. Really, we both understand that we are each six feet tall (or whatever) but we accept that we appear small to each other. The arrangement has a certain symmetry to it in that we each see a similar thing.

However, in relativity, you don't get to automatically expect the same symmetry. If we spent our lives moving relative to each other at very large fractions of the speed of light, we would use a somewhat different idea of common sense. We would still call it “that which agrees with every day observations”. However, because we would observe stuff in very different ways, we would have very different ideas about how the world works.

NoMoreCrazyPeople wrote:
Never ever did I say enything about free, I said "free."

=

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Maybe this is a simple explanation as to why exercise keeps you younger? Simply moving around more slows your clock in contrast with a person with less inertia.

OK, I am not sure if that was intended as a joke or not. Even so, it can be dealt with. Exercise has no bearing on how fast your clock ticks considered to some couch potato sitting next to you. This is actually a part of special relativity. The couch potato is in the same inertial frame of reference as you and thus, both of your wrist watches will agree within the limits of how accurate they are.

However, there is an effect that comes from our understanding of general relativity but it still does not help with your do nothing brother in law. You need to consider two different frames of reference.

Consider some dude who spends most of his time living and working on the top floors of huge skyscrapers. Consider the different frame of reference of some dude who works in retail on street level and lives in a third floor walk up. Because they are in different reference frames, their respective clocks do tick at (very slightly) different rates. In that specific case, the guy on the ground may experience say 100,000 years while the guy in the skyscraper experiences 100,001 years.

As I said above, the effect is so small that for ordinary life, it really doesn't matter. It is real and has been measured by putting atomic clocks on mountain tops. On the other hand, if you were to spend a week in a close orbit of a black hole, then the same effect could manifest as you breaking away from the black hole 100 years after you went into orbit.

NoMoreCrazyPeople wrote:
Never ever did I say enything about free, I said "free."

=

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BobSpence1

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

Edit:  Also is there any solid calculations done that would show how much time difference there would be in regards to how long you travelled and how fast you travelled.  Are we talking seconds over a 5 year journey here, or are we talking a decade on a 2 year journey?

BobSpence
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NoMoreCrazyPeople

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

The factor is

SquareRoot(1 - v2/c2) , where  v is relative velocity, and c is the speed of light.

So if v is 10% of the speed of light, it is

SqRt(1 - 0.1 X 0.1)

= SqRt(1 - 0.01)

= SqRt(0.99)

= 0.995

Time will appear to slow down, to someone else observing you, by 0.5%.

At 50% of c, the factor is 0.866, or 13.4% slowdown

At 1000 mph, the effect is about 1 second in 14000 years....

The calculations for changing velocity are much more complicated.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me

From the sublime to the ridiculous: Science -> Philosophy -> Theology

NoMoreCrazyPeople
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BobSpence1

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

The factor is

SquareRoot(1 - v2/c2) , where  v is relative velocity, and c is the speed of light.

So if v is 10% of the speed of light, it is

SqRt(1 - 0.1 X 0.1)

= SqRt(1 - 0.01)

= SqRt(0.99)

= 0.995

Time will appear to slow down, to someone else observing you, by 0.5%.

At 50% of c, the factor is 0.866, or 13.4% slowdown

The calculations for changing velocity are much more complicated.

So at 60% the speed of light you experience roughly %20 time change, 80% speed of light - %40 tim difference, 90%-57%, 96%-72%, now I'm no great mathmatician but what happens when we the hit the full speed of light here, it's either 0% or 100% time change. Is this time "stopping" or a big big boom, or I am just horrible at math? haha

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NoMoreCrazyPeople

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

The factor is

SquareRoot(1 - v2/c2) , where  v is relative velocity, and c is the speed of light.

So if v is 10% of the speed of light, it is

SqRt(1 - 0.1 X 0.1)

= SqRt(1 - 0.01)

= SqRt(0.99)

= 0.995

Time will appear to slow down, to someone else observing you, by 0.5%.

At 50% of c, the factor is 0.866, or 13.4% slowdown

The calculations for changing velocity are much more complicated.

So at 60% the speed of light you experience roughly %20 time change, 80% speed of light - %40 tim difference, 90%-57%, 96%-72%, now I'm no great mathmatician but what happens when we the hit the full speed of light here, it's either 0% or 100% time change. Is this time "stopping" or a big big boom, or I am just horrible at math? haha

Time would stop.

However, hitting full light speed is considered impossible for anything that has traditional mass since it would require an infinite amount of energy to accomplish.

Everything makes more sense now that I've stopped believing.

robj101
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NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

The factor is

SquareRoot(1 - v2/c2) , where  v is relative velocity, and c is the speed of light.

So if v is 10% of the speed of light, it is

SqRt(1 - 0.1 X 0.1)

= SqRt(1 - 0.01)

= SqRt(0.99)

= 0.995

Time will appear to slow down, to someone else observing you, by 0.5%.

At 50% of c, the factor is 0.866, or 13.4% slowdown

The calculations for changing velocity are much more complicated.

So at 60% the speed of light you experience roughly %20 time change, 80% speed of light - %40 tim difference, 90%-57%, 96%-72%, now I'm no great mathmatician but what happens when we the hit the full speed of light here, it's either 0% or 100% time change. Is this time "stopping" or a big big boom, or I am just horrible at math? haha

Time would stop.

However, hitting full light speed is considered impossible for anything that has traditional mass since it would require an infinite amount of energy to accomplish.

Time would stop but only for whatever is moving at light speed, everything else would still be carrying on.

I'm glad this post helped clear things up for some people, I know some folks who think time is a force but I have managed to enlighten them to the fact that "Time" is like a ruler measuring motion. When motion in general makes it to a certain interval which we call time, then it may be 5 o'clock and "time" to "move" back to the house =).

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

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robj101 wrote:

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

BobSpence1 wrote:

NoMoreCrazyPeople wrote:

Something that I've never really been able to wrap my head around is this if you travel deep into space (at the speed of light I believe)  and turn around and come back more time on earth will have elapsed, or less, or something???  Is this true, and how does this work exactly?  In laymans, enter Bob:

If you observe another object moving at very close to the speed of light with respect to yourself, Einstein's theory of Special Relativity tells us that time in that objects's environment will seem to you to be almost stopped. And that whole moving environment will also appear to very squashed up, shortened, in the direction of its motion.

It gets weirder - to someone moving with that object, you will look the same, clocks almost stopped, and drastically fore-shortened.

These effects are an inevitable consequence/implication of the observed fact that when you measure the speed of light, by any means, whether the distance measures and timing devices you use are moving themselves or not, you will still get the same value.

Now if we want to work out what happens if we stay on the Earth, and a friend gets on an advanced spacecraft and travels at speeds close to light away from Earth then turns around and comes back, we cannot apply the Special Theory by itself since it only applies to thing moving at constant velocity, and the person travelling away at high speed and returning experiences massive acceleration, and this is NOT relative.

An important principle of General Relativity, which includes gravity and non-uniform velocity, is the Equivalence Principle, which states that someone in a closed box will be totally unable to tell the difference between the box being suspended in a uniform gravitational field, and being accelerated upward, with no gravitational field present, at the rate that an object would accelerate in a gravitational field of the same value.

This includes the effect of Gravity on time, and without going thru the math, the person doing all the accelerating and decelerating will have experienced time travelling much more slowly overall than the guy back on Earth.

I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

Hold on I need a couple advil...  So is the believed change in time occurring based on the speed at which one travels or is it a phenomena that only accurs at the speed of light or speeds close to that of light.  For instance if you travelled 1/8 the speed of light would you potentially experience 1/8 the amount of time difference from your earthbound twin as if you were travelling the full speeed of light, or somethign to this effect?  Forgive my complete ignorance on the matter.

The factor is

SquareRoot(1 - v2/c2) , where  v is relative velocity, and c is the speed of light.

So if v is 10% of the speed of light, it is

SqRt(1 - 0.1 X 0.1)

= SqRt(1 - 0.01)

= SqRt(0.99)

= 0.995

Time will appear to slow down, to someone else observing you, by 0.5%.

At 50% of c, the factor is 0.866, or 13.4% slowdown

The calculations for changing velocity are much more complicated.

So at 60% the speed of light you experience roughly %20 time change, 80% speed of light - %40 tim difference, 90%-57%, 96%-72%, now I'm no great mathmatician but what happens when we the hit the full speed of light here, it's either 0% or 100% time change. Is this time "stopping" or a big big boom, or I am just horrible at math? haha

Time would stop.

However, hitting full light speed is considered impossible for anything that has traditional mass since it would require an infinite amount of energy to accomplish.

Time would stop but only for whatever is moving at light speed, everything else would still be carrying on.

I'm glad this post helped clear things up for some people, I know some folks who think time is a force but I have managed to enlighten them to the fact that "Time" is like a ruler measuring motion. When motion in general makes it to a certain interval which we call time, then it may be 5 o'clock and "time" to "move" back to the house =).

Well, I think part of the problem is that it creates a paradox, since time can't totally stop for a single frame of reference.  Sort of like what is the sound of one hand clapping.

I think anyway, I might be wrong.

Everything makes more sense now that I've stopped believing.

robj101
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No it basicly means your

No it basicly means your motion has stopped. You are thinking "time travel" again. Time travel is not possible. When I say your motion has stopped I mean everything in you would have stopped to anyone who could observe you. But matter can't travel the speed of light so, it is impossible either way. This is just a supposition of "what if". If you could travel the speed of light, say for one year real time, no time will have passed for you,much less than a blink and you are a year in the future..

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

BobSpence
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Time doesn't actually stop

Time doesn't actually stop for anyone due to relative motion.

The effects observed for Special Relativity (constant velocity) describe how we observe time apparently slowing down for someone moving at close to the speed of light relative to us.

The person in that other frame will not notice anything themselves, but will in turn see time seeming to slow down for us.

The other related effect is if we try to accelerate something up to the speed of light relative to our frame of reference. It becomes harder and harder, exactly as if the object is becoming much more massive. Which it is, in that its energy of motion has mass itself, according to Einstein's e = mc2 equation. This is routinely observed in particle accelerators. It effectively prevents us from accelerating a particle with mass right up to the speed of light.

The only slow-down we can actually observe in things within our own motional frame of reference is due to gravity. The extreme example of this would be at the event horizon of a black hole, where anything falling in would appear to us to get stuck, since time would stop there. What is weird in this case is that to someone falling in to a black hole, they would not experience time changing at all, for them. They would simply keep falling. Of course, unless it was a very large Black Hole, they would be destroyed by being torn apart by the extreme gravity gradient.

That is a fundamental point in all these time effects. They are only apparent to an observer outside the frame of reference of the one affected by the relative velocity or gravity.

Where the rate of apparent velocity is due to the expansion of space itself, there is no reason why the effective velocity relative to us can't be greater than c, and then we simply cannot see them, since light cannot get back to us. This is why as the Universe expands, parts of it are disappearing from our view completely, as they get to a point where they are receding from us faster than light-speed. We wouldn't be able to 'see' them easily even before they reached c, as the light would have been red-shifted to very long wavelengths, well below the range of visible light.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

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I'm glad I can keep up with

I'm glad I can keep up with Bob on this one despite my lack of scientific terminology and complete lack of study on the matter

Faith is the word but next to that snugged up closely "lie's" the want.
"By simple common sense I don't believe in god, in none."-Charlie Chaplin

RatDog
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Maybe this is a simple explanation as to why exercise keeps you younger? Simply moving around more slows your clock in contrast with a person with less inertia.

OK, I am not sure if that was intended as a joke or not. Even so, it can be dealt with. Exercise has no bearing on how fast your clock ticks considered to some couch potato sitting next to you. This is actually a part of special relativity. The couch potato is in the same inertial frame of reference as you and thus, both of your wrist watches will agree within the limits of how accurate they are.

However, there is an effect that comes from our understanding of general relativity but it still does not help with your do nothing brother in law. You need to consider two different frames of reference.

Consider some dude who spends most of his time living and working on the top floors of huge skyscrapers. Consider the different frame of reference of some dude who works in retail on street level and lives in a third floor walk up. Because they are in different reference frames, their respective clocks do tick at (very slightly) different rates. In that specific case, the guy on the ground may experience say 100,000 years while the guy in the skyscraper experiences 100,001 years.

As I said above, the effect is so small that for ordinary life, it really doesn't matter. It is real and has been measured by putting atomic clocks on mountain tops. On the other hand, if you were to spend a week in a close orbit of a black hole, then the same effect could manifest as you breaking away from the black hole 100 years after you went into orbit.

I might be wrong, but I think that a frame of reference were someone is undergoing acceleration is different than one were someone isn't undergoing acceleration.  So if you had two people at street level and one of them is sitting still while the other one is running around  in circles their clocks tick at very slightly different rate.  The guy running in circle may experience 100,000 years while the guy sitting still may experience 100,001.

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RatDog wrote:

Maybe this is a simple explanation as to why exercise keeps you younger? Simply moving around more slows your clock in contrast with a person with less inertia.

OK, I am not sure if that was intended as a joke or not. Even so, it can be dealt with. Exercise has no bearing on how fast your clock ticks considered to some couch potato sitting next to you. This is actually a part of special relativity. The couch potato is in the same inertial frame of reference as you and thus, both of your wrist watches will agree within the limits of how accurate they are.

However, there is an effect that comes from our understanding of general relativity but it still does not help with your do nothing brother in law. You need to consider two different frames of reference.

Consider some dude who spends most of his time living and working on the top floors of huge skyscrapers. Consider the different frame of reference of some dude who works in retail on street level and lives in a third floor walk up. Because they are in different reference frames, their respective clocks do tick at (very slightly) different rates. In that specific case, the guy on the ground may experience say 100,000 years while the guy in the skyscraper experiences 100,001 years.

As I said above, the effect is so small that for ordinary life, it really doesn't matter. It is real and has been measured by putting atomic clocks on mountain tops. On the other hand, if you were to spend a week in a close orbit of a black hole, then the same effect could manifest as you breaking away from the black hole 100 years after you went into orbit.

I might be wrong, but I think that a frame of reference were someone is undergoing acceleration is different than one were someone isn't undergoing acceleration.  So if you had two people at street level and one of them is sitting still while the other one is running around  in circles their clocks tick at very slightly different rate.  The guy running in circle may experience 100,000 years while the guy sitting still may experience 100,001.

That is correct, to my understanding, but I think the time difference would be much smaller, for the speed a person could run at....

Sorry, I can't give you a figure, the math for this is much more complicated than for simple constant speed effects, got other stuff to do.

Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality

"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

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OK, I am not sure where Bob

OK, I am not sure where Bob is going with that. However, it is fully true that an accelerating frame of reference needs to be understood in different terms from an inertial frame of reference. That is, in fact, why there are two theories of relativity.

To make it clear, let me assume that at some point in the not too distant future, someone figures out how to make a space ship that is capable of a constant acceleration of 1g. For trips around the solar system, you could go to Mars in a few days. You could go to Pluto in a bit over a month.

However, for such short trips, the effects of special relativity don't really mean all that much. If an astronaut were to make a trip to Pluto and back, he would not be more that a couple of minutes younger than his twin brother who stayed on Earth. Even an astronaut who spent a whole 40 year career in interplanetary space would not retire more than a couple of days younger than his earthbound twin.

However, there would be one effect from General Relativity that would be undeniable. Every time the space ship was under power, the astronaut would be able to bounce a rubber ball off the deck exactly as he would on Earth. This is called the equivalence principal.

Now, where Special Relativity comes into play would be with interstellar flight. At a constant acceleration of 1g, it would take a good long while before Special Relativity effects really get interesting.

Basically, after 25 years of Earth time, about 20 years of ship time would have passed. At that point, the ship would be so close to the speed of light that there would be no further gains to be had from keeping the ship under power (apart from using the equivalence principal to generate fake gravity).

However, let's say, just for grins that the mission is to go across the galaxy and come back. How does the situation appear from the ship and from Earth?

As seen from Earth: 25 years of acceleration. Multiply that by 4 for the trip out, the turn around and the return. However, the galaxy is about 100,000 light years wide. Total time for the trip is 100,100 years.

As seen from the ship: 20 years of acceleration. Again we can multiply by 4 for maneuvering. However, once the ship is as close as makes no difference to the speed of light, the whole galaxy will (due to the Lorentz contraction) be a mere 30 light years across. Total time for the trip is 140 years.

BobSpence1 wrote:
I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

OK BobSpence1, I don't see why you are trying to work SR into GR. As I noted above, the twin paradox is fully explained from SR. GR could, at best, provide some minor corrections to the math.

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robj101
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If for some strange reason

If for some strange reason (to go along with the effect you just mentioned) our solar system were to slow down, the speed of our own planet slowing with it, would we speed up? I think if so we would not even notice it, even if it speeded us up signifigantly, it would speed everything up and it would seem normal to us. Much like driving in a van and bouncing a ball, you don't notice any difference but, you and the ball and the van are all moving, unless you hit a bump or make a turn and inertia comes into play, but inertia effects the van as well as you and the ball. The parts make a whole.

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OK, I am not sure where Bob is going with that. However, it is fully true that an accelerating frame of reference needs to be understood in different terms from an inertial frame of reference. That is, in fact, why there are two theories of relativity.

To make it clear, let me assume that at some point in the not too distant future, someone figures out how to make a space ship that is capable of a constant acceleration of 1g. For trips around the solar system, you could go to Mars in a few days. You could go to Pluto in a bit over a month.

However, for such short trips, the effects of special relativity don't really mean all that much. If an astronaut were to make a trip to Pluto and back, he would not be more that a couple of minutes younger than his twin brother who stayed on Earth. Even an astronaut who spent a whole 40 year career in interplanetary space would not retire more than a couple of days younger than his earthbound twin.

However, there would be one effect from General Relativity that would be undeniable. Every time the space ship was under power, the astronaut would be able to bounce a rubber ball off the deck exactly as he would on Earth. This is called the equivalence principal.

Now, where Special Relativity comes into play would be with interstellar flight. At a constant acceleration of 1g, it would take a good long while before Special Relativity effects really get interesting.

Basically, after 25 years of Earth time, about 20 years of ship time would have passed. At that point, the ship would be so close to the speed of light that there would be no further gains to be had from keeping the ship under power (apart from using the equivalence principal to generate fake gravity).

However, let's say, just for grins that the mission is to go across the galaxy and come back. How does the situation appear from the ship and from Earth?

As seen from Earth: 25 years of acceleration. Multiply that by 4 for the trip out, the turn around and the return. However, the galaxy is about 100,000 light years wide. Total time for the trip is 100,100 years.

As seen from the ship: 20 years of acceleration. Again we can multiply by 4 for maneuvering. However, once the ship is as close as makes no difference to the speed of light, the whole galaxy will (due to the Lorentz contraction) be a mere 30 light years across. Total time for the trip is 140 years.

BobSpence1 wrote:
I myself haven't worked out just how all the Special Relativity stuff fits in, but that is mainly an observation of a moving object, everything seems to sort itself out and resolve the potential paradoxes when the effects of acceleration are taken into account, acceleration which is necessary for one or both to experience if they are going to really get back together to directly compare watches.

OK BobSpence1, I don't see why you are trying to work SR into GR. As I noted above, the twin paradox is fully explained from SR. GR could, at best, provide some minor corrections to the math.

Hmm... my understanding is that the Twin Paradox is usually presented as a consequence of the observed slowdown of time in a FoR moving at constant velocity wrt to the observer. Purely by considering SR, there is a paradox, but it can't be argued purely from SR, since one twin has experienced major acceleration and one hasn't. I haven't really tried to work it thru, and haven't seen it laid out like this before.

My biggest problem is the much more complex math than with SR, to work out exactly the time effect of a given acceleration, even for constant acceleration.

Let me think about what you have said here....

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Are the effects of gravity

Are the effects of gravity and acceleration equivalent to each other?

Please consider this situation.  You have to people of equal mass.  Both of these people are standing on scales that are accurate.  Both of them have watches.

Person one is on earth.  He is standing on a bathroom scale that reads 150 lb.

Person two is on a spaceship.  The spaceship is accelerating at a constant rate.  The scale he is standing on reads 150 lb.  At the instance this is happening person one and person two have the exact same velocity.

During the instance in which these two people have the same velocity would their watches be keeping time at the same rate?

Sorry if this is a stupid question.

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RatDog wrote:Are the effects

RatDog wrote:

Are the effects of gravity and acceleration equivalent to each other?

Please consider this situation.  You have to people of equal mass.  Both of these people are standing on scales that are accurate.  Both of them have watches.

Person one is on earth.  He is standing on a bathroom scale that reads 150 lb.

Person two is on a spaceship.  The spaceship is accelerating at a constant rate.  The scale he is standing on reads 150 lb.  At the instance this is happening person one and person two have the exact same velocity.

During the instance in which these two people have the same velocity would their watches be keeping time at the same rate?

Sorry if this is a stupid question.

It is not a silly question.

The Equivalence Principle states exactly that - that there is no way for the observer inside a a frame of reference that is suspended in a constant uniform gravitational field of strength 1g to detect any difference between that and being uniformly accellerated upward at a rate corresponding to 1g. (32ft/sec2 ), in free space, at least by looking at anything within the same frame, including clocks.

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"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris

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RatDog wrote:Are the effects

RatDog wrote:
Are the effects of gravity and acceleration equivalent to each other?

Please consider this situation. You have to people of equal mass. Both of these people are standing on scales that are accurate. Both of them have watches.

Person one is on earth. He is standing on a bathroom scale that reads 150 lb.

Person two is on a spaceship. The spaceship is accelerating at a constant rate. The scale he is standing on reads 150 lb. At the instance this is happening person one and person two have the exact same velocity.

During the instance in which these two people have the same velocity would their watches be keeping time at the same rate?

Sorry if this is a stupid question.

OK, your question is not stupid. However, it is awkwardly set up.

Acceleration is normally handled with general relativity. For the purpose of comparing two clocks, I would start with the equivalence principal. Basically, if you are in an elevator and cannot see the outside world, then you can't know if it is sitting on the ground floor or hurtling through space with an acceleration of 1g.

If we allow a special radio link so that you can communicate with some dude on the outside, then any comparison of the two clocks will show no difference due to gravitational time dilation. That much is quite simple.

However, your setup also assumes elements of special relativity.

Generally, if two clocks on different spacecraft are being compared, what special relativity takes into account is the difference in velocity between them. So if there is no difference in the velocity of the two spacecraft, then we can say that they are stopped relative to each other.

So the question as you have it set up requires both a zero relative velocity and an acceleration of 1g. Do you see the problem here?

That being said, the answer to your question is that there will be no measurable difference between the two clocks. Basically, the way that you would want to set this up would be to think of the Earth Frame of Reference as a set of coordinates in four space and the exact moment that you take the measurement as equivalent to when you pass through the area.

The instant velocity is zero, so special relativity does not provide for a difference. The acceleration is 1g so general relativity provides for no difference.

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