Question on time dilation. Twin Paradox

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pedronascimento33
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Question on time dilation. Twin Paradox

Post by pedronascimento33 »

Imagine you leave your house and start driving, at that time your wife starts a clock to see how long you take.
You drive for 30 minutes going and another 30 minutes back.

Conclusion:
You aged 60 minutes in total
Your wife clocked 60 minutes that you were away.
The speed you were going doesn't matter, it just means you went further if you go faster.
You probably forgot what you went there to get...

Now lets change the minutes by years at speed of light:
You drive 30 years at the speed of light.
For your wife looking at you, you didn´t age for 30 years.
And if you're looking back to your wife while driving, she didn't age for 30 years also.
But in reality 30 years have passed, so you both age 30 years. Even though you're quite far from each other.
As soon and you get there you come back at the same speed which takes you another 30 years.
When you're back 60 years have passed, you're both 60 years older.
And you still probably forgot what you went there to get...

Please explain me where I'm wrong.
ctactawong
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Re: Question on time dilation. Twin Paradox

Post by ctactawong »

Great question! As your title stated, this question is called Twin Paradox which had sparked great scientific discussions. Some points to think about:

(1) When we say "60 years have passed", we need to look at the clock twice: At the beginning and at the end. When we say both the man and the wife's time has passed 60 years, we imply that we are looking at their clocks at the same time, both at the beginning and at the end. The man and his wife won't agree on whether two events happen at the same time. What does relativity say about "simultaneity" (fancy way of saying "at the same time")?

(2) Are there situation truely symmetrical? The wife is standing there and is for sure only in a single reference frame. How about the man? Does he need to change reference frame when he make a round trip? Does he need to accelerate or decelerate? If their situations are not symmetrical, we cannot say its a paradox.
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