- #1
jk4
I am just a little bit unsure about something I read on the "twin paradox".
It talks about Dick and Jane who are twins, each 20yrs old. Dick departs at a speed of 0.80c to a star 20 light years away. So I'm sure you all know how the story goes, Dick is 50yrs old when he returns and Jane is 70.
Ok, then it asks a question:
Dick and Jane each send out a radio signal once a year while Dick is away. How many signals does Dick receive? Hown many does Jane receive? using the same info as above.
I'll leave out a lot of the discussion the book uses and the details, but I'm interested it the fact that the signal rates are different on the return trip then from the outward trip.
Using the doppler effect we find that on the outward trip Dick receives 5 signals from Jane. But, he receives 45 signals from Jane on the return trip.
Now this confuses me because I was under the impression that time would appear to be moving slower for someone moving relative to you regardless of if they are approaching or receding. However, according to this argument, wouldn't it seem that on the return trip that time is moving extremely fast for Jane relative to Dick?
Also, Jane receives 15 signals in 45 years (corresponding to Dicks outward trip), on the return trip Jane receives 15 signals from Dick in the last 5 years of her 50yr wait (the 15 signals Dick sends out on his return), so that means she must see him moving really slow on the outward trip, but then wouldn't it appear to her that he travels 20 light years in just 5 years!
I know I'm wrong because then the theory wouldn't hold, I just want to know what I'm looking at the wrong way.
It talks about Dick and Jane who are twins, each 20yrs old. Dick departs at a speed of 0.80c to a star 20 light years away. So I'm sure you all know how the story goes, Dick is 50yrs old when he returns and Jane is 70.
Ok, then it asks a question:
Dick and Jane each send out a radio signal once a year while Dick is away. How many signals does Dick receive? Hown many does Jane receive? using the same info as above.
I'll leave out a lot of the discussion the book uses and the details, but I'm interested it the fact that the signal rates are different on the return trip then from the outward trip.
Using the doppler effect we find that on the outward trip Dick receives 5 signals from Jane. But, he receives 45 signals from Jane on the return trip.
Now this confuses me because I was under the impression that time would appear to be moving slower for someone moving relative to you regardless of if they are approaching or receding. However, according to this argument, wouldn't it seem that on the return trip that time is moving extremely fast for Jane relative to Dick?
Also, Jane receives 15 signals in 45 years (corresponding to Dicks outward trip), on the return trip Jane receives 15 signals from Dick in the last 5 years of her 50yr wait (the 15 signals Dick sends out on his return), so that means she must see him moving really slow on the outward trip, but then wouldn't it appear to her that he travels 20 light years in just 5 years!
I know I'm wrong because then the theory wouldn't hold, I just want to know what I'm looking at the wrong way.
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