Understanding Time Dilation: Explained with an Everyday Example | Help Needed"

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Homework Help Overview

The discussion revolves around the concept of time dilation in the context of special relativity. The original poster presents a scenario involving a stationary clock on Earth and a clock on a spacecraft, questioning how both clocks can show the same time after a journey when time dilation suggests otherwise.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the implications of time dilation, questioning the assumptions made about the experiences of observers on the spacecraft versus those on Earth. There is a discussion about the effects of relative motion on the perception of time and distance.

Discussion Status

The discussion is active, with participants providing insights into the nature of time dilation and length contraction. Some guidance has been offered regarding the differing perceptions of time between observers in different frames of reference, but no consensus has been reached.

Contextual Notes

There is a mention of the need for clarity on the concept of time dilation and the assumptions underlying the original poster's scenario. The discussion acknowledges the complexity of the topic and the potential for misunderstanding the effects of high-speed travel.

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Time Dilation --- Help needed

Homework Statement



Time dilation says, " Moving clocks run slow".

Homework Equations





The Attempt at a Solution


For example, a stationary clock shows 4 PM and at the same 4 PM a spacecraft moves with a clock inside it showing the same 4 PM. Now after an hour, the spacecraft returns to earth. The stationary clock will show 5 PM. I presume the clock in the spacecraft will also show 5 PM. Then how can we say moving clocks run slow. Forgive if i sound silly. I need clarity on this concept. Thanks in advance
 
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The idea of time dilation is that light moves at the same constant rate seen from any perspective and that other moving objects don't. As you move faster you're perception of reality has a decreased rate. Everything else appears slower to you. To find the time distortion you would use Einstein's equation:

t' = (1-velocity/speed of light)^-(1/2)

Whichever clock is moving faster is going to be the clock that reads the earlier time.
 


You are assuming that the observers on the spaceship will say that they spent 1 hour traveling. But this does not happen; the spaceship observers will see the distance between the Earth and themselves to be contracted, which is another affect of traveling at high speeds (length contraction). So when the spaceship observers see themselves reaching the Earth by traveling a different distance than the Earth observers say, they will show a different time than the Earth observers (depending on the speed they travel at).
 


Thanks everyone for your replies
 

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