Can time pass slower on another planet, causing the Twin Paradox?

[Dale]

So why are we concluding that time is not absolute

Did you miss my easier scenario in post 29?

 

[Mister T]

Does it mean that time dilation occurs because the observer in moving train consider himself at rest while he is not.

There is no difference between being at rest and moving in a straight line at a steady speed. To say that you are "really" doing one but not the other is meaningless.

So why are we concluding that time is not absolute for the observer in moving train while the reality is he does not know that he is moving w.r.t the events that has been occurred.

Time is not absolute. For anyone. Think of it this way. Suppose there's a giant clock in the sky that keeps track of time. Any event that happens anywhere in the universe can be assigned a time coordinate equal to the reading on that giant clock. But of course there is no giant clock in the sky, meaning there is no sense in which a specific time coordinate can be assigned to distant events that will be the same for all observers. The time coordinate is thus relative, not absolute.

 

[Sagittarius A-Star]

As from the second postulate of Einstein special theory of relativity the speed of light is always constant.
That means one second is always constant so this rules out the possibility of one being younger than other.

No. The SI second definition shall be understood in the following way:

The definition of the second should be understood as the definition of the unit of proper time: it applies in a small spatial domain which shares the motion of the caesium atom used to realize the definition. In a laboratory sufficiently small to allow the effects of the non-uniformity of the gravitational field to be neglected when compared to the uncertainties of the realization of the second, the proper second is obtained after application of the special relativistic correction for the velocity of the atom in the laboratory. It is wrong to correct for the local gravitational field.

Source (see chapter 3.1):
https://www.bipm.org/utils/en/pdf/si-mep/SI-App2-second.pdf

The caesium atom is moving in the atomic clock, therefore it has a slower tick-rate in the lab frame. That has to be corrected. In newer atomic clocks the caesium atoms are cooled down with lasers, so that they have a very small velocity.

The following animation of a "light clock" shows you, why the 2nd SR postulate (speed of light is c in every inertial frame) implies, that a moving clock ticks slower than a clock at rest in the given reference system:

https://www.pitt.edu/~jdnorton/teac...ty_clocks_rods/figures/light_clock_anim_2.gif

For an observer moving together with the moving clock, it has a normal tick rate.

 

[Satyam]

As you all are saying that events are indipendent of Frame of reference but it is little difficult for me to get it.
Let's look at these definitions
Frame of reference: It consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements within that frame.

Event: An event is the instantaneous physical situation or occurrence associated with a point in spacetime (that is, a specific place and time). For example, a glass breaking on the floor is an event; it occurs at a unique place and a unique time.

Hence An event occurs at a particular space at a particular time. So when it is occurring in a particular space how can we say that it is indipendent of Frame of reference because in order to know the place where the event has been occurred we have to make use of frame of references or in order to encounter the event we have to use frame of reference otherwise how would you that an event has been occurred. I'm saying that because we measure everything from a reference. Either it is time or space? ...so how can an event be indipendent of frame of reference??

 

[PeroK]

As you all are saying that events are indipendent of Frame of reference but it is little difficult for me to get it.
Let's look at these definitions
Frame of reference: It consists of an abstract coordinate system and the set of physical reference points that uniquely fix (locate and orient) the coordinate system and standardize measurements within that frame.

Event: An event is the instantaneous physical situation or occurrence associated with a point in spacetime (that is, a specific place and time). For example, a glass breaking on the floor is an event; it occurs at a unique place and a unique time.

Hence An event occurs at a particular space at a particular time. So when it is occurring in a particular space how can we say that it is indipendent of Frame of reference because in order to know where the place where the event has been occurred we have to make use of frame of references...so how can it be indipendent of frame of reference??

The event itself is a physical occurrence (or just a point in spacetime). That has nothing to do with reference frames, as such. A reference frame is a way of giving a unique set of coordinates to every event.

 

[Sagittarius A-Star]

So when it is occurring in a particular space how can we say that it is indipendent of Frame of reference because in order to know the place where the event has been occurred we have to make use of frame of references or in order to encounter the event we have to use frame of reference otherwise how would you that an event has been occurred.

It is not possible to encounter the event after it has happened. To encounter an event, you have to have the same x-, y-, z and t-coordinate as the event. Assume, your glass breaking happens in a window of the moving train. The windows frame (an object) is moving with the train, but not the glass breaking (an event).

An object, moving with the train, needs to have in the embankment frame the velocity
v= (x2 - x1)/(t2 - t1). But an event has only one t-coordinate and not a "t2 - t1". So it cannot have a velocity and therefore also not a velocity of Zero (=beeing at rest) in a certain reference frame.

 

[Satyam]

All events happen in both frames of reference. It makes no sense to say that an event happens in one frame but not in another.

In each reference frame we can assign a time coordinate and a position coordinate to each event.

Trying to explain what those coordinates are in one frame given the coordinates in another frame is the purpose of a theory of relativity.

Thank you sir I think this statement is appropriate and I have understood that events happens to be different at different frame of reference because an observer would assign the time and coordinate to that event according to his frame of reference. And that results in different opinions.
Hence both observers are right acc. to their frame of reference. One observer trying to understand how the other observer would experience that event is the essence of relativity.. Am I right?

 

[Satyam]

There is no difference between being at rest and moving in a straight line at a steady speed. To say that you are "really" doing one but not the other is meaningless.
Time is not absolute. For anyone. Think of it this way. Suppose there's a giant clock in the sky that keeps track of time. Any event that happens anywhere in the universe can be assigned a time coordinate equal to the reading on that giant clock. But of course there is no giant clock in the sky, meaning there is no sense in which a specific time coordinate can be assigned to distant events that will be the same for all observers. The time coordinate is thus relative, not absolute.

As we know in this cosmos what we call as time is essentially the cyclical nature of Physical entities.
The Earth makes one rotation we call it a day, it makes one revolution around the sun we call it a year. For more precision, 9,192,631,770 cycles of radiation of transition between two energy levels of cesium-133 is one second.
As we know that Earth is spinning around the sun, our solar system is spinning around the milkiway galaxy and so on.
So does it mean that there is actually a fundamental dimension of absolute time which we are not familiar with and we cannot experience it due to our limitations of space and time.., as we are trapped in it.?

 

[jedishrfu]

No. There is no absolute space. There is no absolute time. There is only spacetime.

You are still thinking like a Newtonian scientist. Now we must think in a relative fashion and realize that our measurements are based on our own frame of reference and no other.

Our only guiding principle is that the speed of light is the same for all observers and is based firmly on experimental observation.

Since this thread has run its course and the OP's question has been answered, its a good time the thank everyone who contributed and to close it now.