A spaceship moving near the speed of light

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Discussion Overview

The discussion revolves around the effects of time dilation on a spaceship moving near the speed of light, exploring theoretical implications for time perception both inside and outside the spaceship, as well as the behavior of objects and space within the ship from the perspective of an observer on Earth.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that time dilation occurs only in and around the spaceship, questioning how far this effect extends beyond its physical boundary.
  • There are inquiries about whether an object, such as an antenna extending from the spaceship, would experience time dilation and if the entire space between the bottom and top of the antenna would also be affected.
  • Some participants assert that anything moving near the speed of light will appear to move slower relative to an observer, emphasizing that this effect is independent of distance.
  • There are discussions about the implications of a hollow spaceship and whether the space inside it could be considered to be moving slower compared to Earth.
  • Participants express confusion about the concept of "empty space" moving and its relationship to time dilation, with some suggesting that quantum fluctuations in space might also experience time dilation.
  • One participant argues that time dilation is a matter of perspective, stating that all processes appear slower when in motion relative to an observer, and that there is no absolute slowing down of time.
  • Another participant suggests that if the spaceship were to return to Earth, there would be an objective difference in accumulated time on the spaceship's clocks compared to those on Earth.

Areas of Agreement / Disagreement

Participants express varying views on the nature of time dilation, with some asserting it is a perspective effect while others suggest it has measurable implications. The discussion remains unresolved with multiple competing views on how time dilation operates in relation to moving objects and the concept of space.

Contextual Notes

There are limitations in the discussion regarding the definitions of time dilation, the nature of empty space, and the assumptions about the behavior of objects at relativistic speeds. The mathematical and physical principles underlying these concepts are not fully explored or agreed upon.

Naveen3456
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A spaceship moves near the speed of light. Its time becomes slow for an observer on earth.

1. Does 'time' slow only in and around ( i.e. the space inside and outside) the spaceship? If yes, to what extent ( i.e. how much meters or centimeters) above the physical boundary of spaceship.

2. Suppose, the spaceship has something vertically projected from it ( a thin antenna etc.) that reaches a height of 100 km (or even 100000000...km, just suppose). There is a watch at top of this antenna.

a) Would it also slow down?

b) Would all the space between bottom to top of this antenna experience slowing of time, as seen by an observer on earth?
 
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Naveen3456 said:
A spaceship moves near the speed of light. Its time becomes slow for an observer on earth.

1. Does 'time' slow only in and around ( i.e. the space inside and outside) the spaceship? If yes, to what extent ( i.e. how much meters or centimeters) above the physical boundary of spaceship.

2. Suppose, the spaceship has something vertically projected from it ( a thin antenna etc.) that reaches a height of 100 km (or even 100000000...km, just suppose). There is a watch at top of this antenna.

a) Would it also slow down?

b) Would all the space between bottom to top of this antenna experience slowing of time, as seen by an observer on earth?
Time for everything that is moving in the Earth rest frame is dilated. It's as simple as that.
 
Naveen3456 said:
A spaceship moves near the speed of light. Its time becomes slow for an observer on earth.

1. Does 'time' slow only in and around ( i.e. the space inside and outside) the spaceship? If yes, to what extent ( i.e. how much meters or centimeters) above the physical boundary of spaceship.

2. Suppose, the spaceship has something vertically projected from it ( a thin antenna etc.) that reaches a height of 100 km (or even 100000000...km, just suppose). There is a watch at top of this antenna.

a) Would it also slow down?

b) Would all the space between bottom to top of this antenna experience slowing of time, as seen by an observer on earth?
Any thing that is moving near the speed of light, relative to an observer, will be moving slower compared to that observer. It has nothing to do with distance.
 
HallsofIvy said:
Any thing that is moving near the speed of light, relative to an observer, will be moving slower compared to that observer. It has nothing to do with distance.

Suppose the air ship is hollow from inside and is air tight ( or there is vacuum inside it).

Can we say that now 'space' itself is moving slower compared to the observer?
 
Naveen3456 said:
Suppose the air ship is hollow from inside and is air tight ( or there is vacuum inside it).

Can we say that now 'space' itself is moving slower compared to the observer?
If there is air in the ship, then each atom and molecule will be time dilated according to the Earth frame.

What is the meaning of empty space moving?
 
ghwellsjr said:
If there is air in the ship, then each atom and molecule will be time dilated according to the Earth frame.

What is the meaning of empty space moving?

I heard a scientist saying on the discovery channel, ' This universe is not expanding into empty space, it is creating 'space' while it expands.'

So anything which is created can be called a 'thing' ( a noun).

So, I was talking about this space-thing (inside the spaceship) to be moving slower as compared to earth.

I hope I don't sound ripe for an asylum.
 
Naveen3456 said:
I heard a scientist saying on the discovery channel, ' This universe is not expanding into empty space, it is creating 'space' while it expands.'

So anything which is created can be called a 'thing' ( a noun).

So, I was talking about this space-thing (inside the spaceship) to be moving slower as compared to earth.

I hope I don't sound ripe for an asylum.
I think the scientist was trying to point out that without matter, there is no meaning to empty space.
 
ghwellsjr said:
I think the scientist was trying to point out that without matter, there is no meaning to empty space.

when space is said to have quantum fluctuations, why can't it be called a 'thing'?
 
Naveen3456 said:
when space is said to have quantum fluctuations, why can't it be called a 'thing'?
You're on the wrong forum for questions like that.

The only sense in which empty space can have time associated with it is with regard to the coordinate time defined by a given Inertial Reference Frame (IRF) and there is no motion associated with any coordinate time. So in the Earth's IRF, the spaceship's time is dilated but the coordinate time for the region of empty space inside the spaceship is not time dilated. Time Dilation is the ratio of the time a moving clock (or anything) accumulates to the accumulation of coordinate time. The speed of each item with respect to the chosen IRF determines its Time Dilation. If different things have different speeds, they will have different Time Dilations.

So if there are molecules inside the hollow ship and they are traveling at different speeds, each individual molecule will have its own different Time Dilation. How would you identify the speed of the space between the different molecules?

I don't know how to communicate the concept to you any more clearly than that. It seems that you'd like this thread to go in some direction but I have no idea what you're looking for. Time Dilation is a very simple concept as I said in my first post. I don't know why you want to make it complicated.
 
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  • #10
ghwellsjr said:
You're on the wrong forum for questions like that.

The only sense in which empty space can have time associated with it is with regard to the coordinate time defined by a given Inertial Reference Frame (IRF) and there is no motion associated with any coordinate time. So in the Earth's IRF, the spaceship's time is dilated but the coordinate time for the region of empty space inside the spaceship is not time dilated. Time Dilation is the ratio of the time a moving clock (or anything) accumulates to the accumulation of coordinate time. The speed of each item with respect to the chosen IRF determines its Time Dilation. If different things have different speeds, they will have different Time Dilations.

So if there are molecules inside the hollow ship and they are traveling at different speeds, each individual molecule will have its own different Time Dilation. How would you identify the speed of the space between the different molecules?

I don't know how to communicate the concept to you any more clearly than that. It seems that you'd like this thread to go in some direction but I have no idea what you're looking for. Time Dilation is a very simple concept as I said in my first post. I don't know why you want to make it complicated.

I can't make anything complicated.

I just want to say that the quantum fluctuations of the space 'inside' the spaceship will also slow down ( if they are visible/detectable at all!)
 
  • #11
Time does not get slowed down. It is just a matter of perspective, point of view effect. All processes 'seem' to go slower when they seem to be moving, and seem faster when they seem stationary. Clocks on the ship seem slower, but to the people on board clocks on Earth seem slower. There is no actual absolute objective slowing down of anything.
 
  • #12
georgir said:
Time does not get slowed down. It is just a matter of perspective, point of view effect. All processes 'seem' to go slower when they seem to be moving, and seem faster when they seem stationary. Clocks on the ship seem slower, but to the people on board clocks on Earth seem slower. There is no actual absolute objective slowing down of anything.
Maybe not in this thread's scenario, but if that spaceship ever returned to Earth there would be an actual objective reduction in the accumulated time on the spaceship's clocks compared to the Earth's clocks, don't you agree?
 

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