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  #1 (permalink)  
Old 09-May-2008, 08:46 AM
Simsthefat Simsthefat is offline
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Default time and mobement?

As I sit here writing this, I would appear to be motionless. In actuality, I am moving at a speed that would impress even the most dangerous of thrill seakers. Don't fret Sean White, we're in this together. As our home spins on its axis it carries us along with it. And as our home makes it annual journey around our star, our speed increases. As our star travels in the soft spiral arms around the center of our galaxy, our apparently motionless lazy day actions are all most completely shattered! As the immense power of the big bang carries us still faster still. We can now see that even while traveling faster than the speed of sound, we are traveling much faster.
Not to mention the effects dark matter may have on our motion.

My first question is, how fast are we moving?

Secondly, what would happen to time if I completely stopped and let all of that wiz by me?

Last, but most definitely not least is, since the only two things that I can tell are constant are time and movment. Are they one in the same? Is what we experience as time only a side effect to our movment?
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Old 09-May-2008, 02:45 PM
Jeff Root Jeff Root is offline
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Hey there!

Quote:
Originally Posted by Simsthefat View Post
My first question is, how fast are we moving?
Relative to what?

Linear motion is relative. It can only be measured relative to something.
Rotation on the other hand, is absolute. There are ways you can tell
whether you are rotating or not without having to compare your motion,
position, or orientation to anything. Not so with linear motion.

Complicating that is the fact that linear motion is part of all rotation.
For example, Earth rotates once per sidereal day (23 hours, 56 minutes),
so a point on the equator has a linear velocity of 465 m/s to the east,
relative to an imaginary point at Earth's center. Earth revolves around
the Sun once per sidereal year (365.2564 days), so it has a linear speed
of about 30 km/s relative to a point at the center of the Sun. The Sun
and Solar System revolve around the center of the Milky Way roughly
once per 230 million years, so it has a linear speed of roughly 300 km/s
relative to a point at the center of the galaxy.

What is interesting is that on the largest scale at which we are able to
measure our own speed, there is something available for us to measure
against. That is the cosmic background radiation (CBR). We don't
actually measure our speed relative to the light itself, but in effect we
measure our speed and direction of motion relative to the matter which
emitted the light 13.7 billion years ago, by comparing the amount of
redshift of the CBR in different directions. It shows that the center of
the Milky Way galaxy is moving at roughly 600 km/s. (I tried to find the
direction it is in but didn't get a clear answer. It looks like it might be
a bit southeast of the constellation Leo.) This speed and direction is
determined by measuring the redshift of the CBR at Earth, then removing
the redshift due to the motions of the Earth described above. The
measurements show that the Earth itself has a net motion relative to
the matter which emitted the CBR of roughly 400 km/s in the direction
of the constellation Leo. (11 hours R.A., 6 degrees north latitude)

Quote:
Originally Posted by Simsthefat View Post
Secondly, what would happen to time if I completely stopped and let all
of that wiz by me?
Relative to what?

If you slowed down your speed of motion in orbit around the center of
the galaxy, and maintained your position using rockets to prevent you
from falling toward the center, your clocks would appear to slow very
slightly as viewed by those whizzing past you.

Quote:
Originally Posted by Simsthefat View Post
Last, but most definitely not least is, since the only two things that I
can tell are constant are time and movment. Are they one in the same?
Is what we experience as time only a side effect to our movment?
This has been discussed on BAUT before. I would say that time is
measured by movement, but I would not say that time is movement,
nor that time is a side effect of movement. Time is what you measure
with clocks, but time evidently passes whether there is any kind of
clock (manmade or naturally-existing) to measure it or not. Time is
part of the measurement of all change, and all change appears to
involve motion. So you are right at least to the extent that motion is
intimately involved with time, and our perception of time.

-- Jeff, in Minneapolis
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Old 09-May-2008, 05:52 PM
Simsthefat Simsthefat is offline
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I would think that, as we are always moving that this may have something to do with how we experience time. I also thought that the faster you go, the slower my clock would tick compared to someone moving slower than I? My thought would be, if i could completely stop and stay in the same spot which i currently am in the universe, zero movement, that my clocks would speed up out of control? No? Why would my clock slow as I slowed down?
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Old 09-May-2008, 06:13 PM
Simsthefat Simsthefat is offline
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Also, As I can not to get to point A to point B without the passage of time would it still be possible to get from time A to time B without movement of any kind?
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Old 09-May-2008, 08:25 PM
Jeff Root Jeff Root is offline
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Quote:
Originally Posted by Simsthefat View Post
I also thought that the faster you go, the slower my clock would
tick compared to someone moving slower than I?
If two people with clocks are moving linearly past each other, the
faster they are moving relative to each other, the slower the other
person's clock appears to be ticking.

If one person with a clock is accelerating in a circle at constant speed
near another person with a clock, who is not accelerating, the clock
going in a circle will appear to be ticking slow to the other person, and
that other person's clock will appear to be going fast to the person
who is accelerating.

Quote:
Originally Posted by Simsthefat View Post
My thought would be, if i could completely stop and stay in the same
spot which i currently am in the universe, zero movement, that my
clocks would speed up out of control? No? Why would my clock slow
as I slowed down?
Stay in the same spot relative to what? All linear motion is relative.
Every measurement of position and speed is relative to something else.
You can measure the speed of two bodies relative to each other, but
neither body is moving faster than the other.

-- Jeff, in Minneapolis
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Old 09-May-2008, 09:09 PM
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cosmocrazy cosmocrazy is offline
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Quote:
Originally Posted by Simsthefat View Post
Also, As I can not to get to point A to point B without the passage of time would it still be possible to get from time A to time B without movement of any kind?
Jeff has explained to you about relativity, this answers your questions about relative speed and time.

What do you mean by no "movement of any kind" are you talking about absolute zero in temperature? For this is what would be required for zero motion all the way down to the quantum level. If you were hypothetically able to measure yourself having no spatial motion relative to everything in the universe then you would still be moving in time.
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Old 10-May-2008, 05:39 PM
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Bogie Bogie is offline
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Quote:
Originally Posted by Jeff Root View Post
If two people with clocks are moving linearly past each other, the
faster they are moving relative to each other, the slower the other
person's clock appears to be ticking.

If one person with a clock is accelerating in a circle at constant speed
near another person with a clock, who is not accelerating, the clock
going in a circle will appear to be ticking slow to the other person, and
that other person's clock will appear to be going fast to the person
who is accelerating.


Stay in the same spot relative to what? All linear motion is relative.
Every measurement of position and speed is relative to something else.
You can measure the speed of two bodies relative to each other, but
neither body is moving faster than the other.

-- Jeff, in Minneapolis
I used Bold to highlight a phrase you used. Do you mean acceleration at a constant rate, i.e. continuing to accelerate, or does the same effect occur when there is relative movement without continual acceleration?
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Old 10-May-2008, 06:12 PM
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Michael Noonan Michael Noonan is offline
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Quote:
Originally Posted by Bogie View Post
I used Bold to highlight a phrase you used. Do you mean acceleration at a constant rate, i.e. continuing to accelerate, or does the same effect occur when there is relative movement without continual acceleration?
A circle or an orbit has two components. The forward movement or the direction the orbit takes is a velocity and is the constant. The gravitation towards the body being orbited say in orbit around a planet is an acceleration towards the planet so the acceleration is constant also at each point in the orbit towards the planet.

By having an acceleration due to gravity even though the speed of orbit stays the same brings in frame dragging through space and over a suitable interval can be measured as a difference in recorded time between the person holding one clock on the planet and the other person holding a second clock on the orbiting vehicle.

When it is done with planes the gravity is still present but the lift of the wings replaces the need to maintain a velocity in orbit and can be replaced by the velocity of the aeroplane but it is the action of gravity or if you like the acceleration toward the planet which causes frame dragging that makes the difference.
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Old 10-May-2008, 06:22 PM
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Bogie Bogie is offline
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Quote:
Originally Posted by Michael Noonan View Post
A circle or an orbit has two components. The forward movement or the direction the orbit takes is a velocity and is the constant. The gravitation towards the body being orbited say in orbit around a planet is an acceleration towards the planet so the acceleration is constant also at each point in the orbit towards the planet.

By having an acceleration due to gravity even though the speed of orbit stays the same brings in frame dragging through space and over a suitable interval can be measured as a difference in recorded time between the person holding one clock on the planet and the other person holding a second clock on the orbiting vehicle.

When it is done with planes the gravity is still present but the lift of the wings replaces the need to maintain a velocity in orbit and can be replaced by the velocity of the aeroplane but it is the action of gravity or if you like the acceleration toward the planet which causes frame dragging that makes the difference.
Of course, thank you for your explanation. So there is constant acceleration in Jeff Root's example.

If a circumstance were imagined where two clocks traveling through space at two different speeds showed the same time on them, and then one accelerated to reach the exact speed of the other ending up traveling parallel in close enough proximity, then they would show a time difference due to the period of acceleration of the one clock but the time difference would remain constant once they were traveling in sync?
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Old 10-May-2008, 06:43 PM
Jeff Root Jeff Root is offline
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Quote:
Originally Posted by Bogie View Post
Quote:
Originally Posted by Jeff Root
If one person with a clock is accelerating in a circle at constant speed
near another person with a clock, who is not accelerating,
I used Bold to highlight a phrase you used. Do you mean acceleration
at a constant rate, i.e. continuing to accelerate, or does the same effect
occur when there is relative movement without continual acceleration?
Motion in a circle only occurs when there is acceleration toward the
center of that circle. I was referring to motion in a circle at constant
speed relative to the center of the circle. The acceleration could be
provided by the gravity of a planet, or by firing your rocket engines
directly away from the center of the circle you want to make. Either
way, your speed remains constant.

-- Jeff, in Minneapolis
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Old 10-May-2008, 07:11 PM
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Michael Noonan Michael Noonan is offline
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Quote:
Originally Posted by Bogie View Post
Of course, thank you for your explanation. So there is constant acceleration in Jeff Root's example.

If a circumstance were imagined where two clocks traveling through space at two different speeds showed the same time on them, and then one accelerated to reach the exact speed of the other ending up traveling parallel in close enough proximity, then they would show a time difference due to the period of acceleration of the one clock but the time difference would remain constant once they were traveling in sync?
Yes the clocks run in sync as soon as they are not accelerating differently and are at the same point from the centre of gravity so that the conditions are the same. You can do that outwards or it is the same as bringing the clocks back together when landing the plane. You can compare them for difference while you were travelling apart and synchronize when meeting again.
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Old 10-May-2008, 07:17 PM
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Michael Noonan Michael Noonan is offline
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Quote:
Originally Posted by Jeff Root View Post
Motion in a circle only occurs when there is acceleration toward the
center of that circle. I was referring to motion in a circle at constant
speed relative to the center of the circle. The acceleration could be
provided by the gravity of a planet, or by firing your rocket engines
directly away from the center of the circle you want to make. Either
way, your speed remains constant.

-- Jeff, in Minneapolis
Quite right it works for constant acceleration even if you just hover and do not orbit. That way the velocity is in line with the direction of acceleration and not at right angles as if maintaining an orbit.

A similar effect could be achieved by using a suitably long ladder.
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Old 11-May-2008, 01:27 AM
dcl dcl is offline
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Simsthefat: My first question is, how fast are we moving? Secondly, what would happen to time if I completely stopped and let all of that wiz by me?
Last, but most definitely not least is, since the only two things that I can tell are constant are time and movment. Are they one in the same? Is what we experience as time only a side effect to our movment?

dcl: The speeds of the earth around the sun and around the center of the Milky Way galaxy are about 22 and 30 mi/sec., respectively. Nothing would happen to your perception of time. Time and movement are not the same. Movement does not affect our perception of passage of time as meassured in our own frame of reference, but it appears to us that time passes more slowly in a frame of reference that is moving with respect to us. Time also appears to us at points in a gravitational field stronger than that in our own location.
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