Is Time Travel Possible and Already Happening in Our World?

[isly ilwott]

True, I was trying to explain to isly that you can easily define motion as a change in distance, but furthermore that an object will never be in absolute zero motion.

Motion is nothing more than a change in position. It does not have to involve a change in distance. A spinning sphere is in motion though it's center may be stationary and you may not be able to detect the motion without studying the surface. If there are no imperfections in a polished sphere with a single color finish, you would be hard put to detect the spinning motion...but the sphere is still moving.

Please be more correct when trying to explain things to me.

 

[dkgolfer16]

Space beer! I'm sure sending beer into space so it matures faster is very cheap and efficient!

I think you are very confused. Sending the beer into space at some fraction of c would cause it to age slower...

 

[MeJennifer]

Motion is nothing more than a change in position.

Under relativity this statement absolutely makes no sense, there are no positions. Motion is simply a change in distance.

A spinning sphere is in motion though it's center may be stationary and you may not be able to detect the motion without studying the surface.

You perhaps mistake motion with acceleration. Each point on a spinning ball, except for the center is accelerating and all points are in motion with respect to each other. However this motion is only significant at relativistic speeds.

 

[isly ilwott]

Under relativity this statement absolutely makes no sense, there are no positions. Motion is simply a change in distance.


You perhaps mistake motion with acceleration. Each point on a spinning ball, except for the center is accelerating and all points are in motion with respect to each other. However this motion is only significant at relativistic speeds.

Bullfeathers!

I am quite familiar with angular acceleration. As each point within and on the surface of the sphere is accelerated toward the axis of rotation, it experiences curvilinear motion...of a circular pattern.

Curvilinear motion involves changes in distance of any non-center point (or molecule, if you will) from it's previous position...regardless of the non-zero angular velocity.

By the way, two distinct points anywhere within a spinning sphere are not in motion relative to each other, even though they are both in cyclical motion relative to a fixed point outside of the sphere.

 

[MeJennifer]

I am quite familiar with angular acceleration. As each point within and on the surface of the sphere is accelerated toward the axis of rotation, it experiences curvilinear motion...of a circular pattern.

Ok so we do not seem to disagree on that one.

Curvilinear motion involves changes in distance of any non-center point (or molecule, if you will) from it's previous position...regardless of the non-zero angular velocity.

You are ignoring the principles of relativity again. Remember motion is always relative in relativity!

By the way, two distinct points anywhere within a spinning sphere are not in motion relative to each other, even though they are both in cyclical motion relative to a fixed point outside of the sphere.

It seems that you understand that motion is relative as you write now: "motion relative to a fixed point outside of the sphere"! However you are mistaken about the first part, all the points except for the center are in motion with respect to each other. You might want to consult the literature about relativity and rotating disks or balls.

By the way, I presume you mean a ball instead of a sphere as a sphere does not even have a center.

 

[MeJennifer]

I am quite familiar with angular acceleration. As each point within and on the surface of the sphere is accelerated toward the axis of rotation, it experiences curvilinear motion...of a circular pattern.

Ok so we do not seem to disagree on that one.

Curvilinear motion involves changes in distance of any non-center point (or molecule, if you will) from it's previous position...regardless of the non-zero angular velocity.

You are ignoring the principles of relativity again. Remember motion is always relative in relativity!

By the way, two distinct points anywhere within a spinning sphere are not in motion relative to each other, even though they are both in cyclical motion relative to a fixed point outside of the sphere.

It seems that you understand that motion is relative as you write now: "motion relative to a fixed point outside of the sphere"! However you are mistaken about the first part, all the points except for the center are in motion with respect to each other. You might want to consult the literature about relativity and rotating disks or balls.

By the way, I presume you mean a ball instead of a sphere as a sphere does not even have a center.

I seems that the problem you are having is that you think in terms of absolute positions and locations. There are no such things in relativity as 'positions' and 'locations' are only relative concepts.

 

[isly ilwott]

Ok so we do not seem to disagree on that one.

Being so simple, it would be difficult to disagree on that one.

You are ignoring the principles of relativity again. Remember motion is always relative in relativity!

I've not ignored it...and motion is always relative (period).

It seems that you understand that motion is relative as you write now: "motion relative to a fixed point outside of the sphere"! However you are mistaken about the first part, all the points except for the center are in motion with respect to each other. You might want to consult the literature about relativity and rotating disks or balls.

Simplify this to a disc. Consider two fixed horses on a spinning Merry-Go-Round. They are not in motion relative to each other. They are both in motion relative to an observer standing in the ticket line.

By the way, I presume you mean a ball instead of a sphere as a sphere does not even have a center.

There are hollow spheres and solid spheres. Both have centers. By your way of thinking, a perfect circle drawn on a sheet of paper has no center.

The center of a sphere is simply that one and only one point that is equally distant from every point on the surface of the sphere, whether the sphere is hollow or not.

I seems that the problem you are having is that you think in terms of absolute positions and locations. There are no such things in relativity as 'positions' and 'locations' are only relative concepts.

Of course there are. The very idea of relativity depends on positions and locations.

It will be scary to ever see MENTOR under your name.

 

[MeJennifer]

There are hollow spheres and solid spheres. Both have centers. By your way of thinking, a perfect circle drawn on a sheet of paper has no center.

Do you understand the difference between a ball and a sphere or a disk and a circle?

 

[isly ilwott]

Do you understand the difference between a ball and a sphere or a disk and a circle?

Is that ever a rhetorical question?

I realize that mathematicians consider only the surface, but they still call the centerpoint the center. It is not part of the sphere but is its center. The samer holds for the circle drawn on paper. It still has a center...that is not part of the circle.

The word "sphere" has Greek origins "sphaira, ball".

 

[MeJennifer]

I realize that mathematicians consider only the surface, but they still call the centerpoint the center.

A sphere has no center.

At any rate it seems I cannot be helpful to you, so I leave it at that.

 

[matheinste]

Hello isly ilwott.

I suppose the surface of a sphere is a two dimensional manifold and has no centre. But it is normal and common usage to refer to the centre of the volume it encloses when thought of as being embedded in three dimensional space ( a ball ), as the centre of the sphere. We all know what it means.

Matheinste.