The Twin Paradox - 60-Second Adventures in Thought (5/6)

An identical twin in space illustrates Einstein's special theory of relativity.

(Part 5 of 6)

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[glitchfan]

If they were on the phone with each other the whole time, the twin on Earth would begin to experience longer and longer wait times for a response from his twin, while the only thing the traveler would experience is his twin's voice sounding older and older. For the traveler, it would be like a normal conversation (except for his twin's voice getting older).

[dylanhendrixfloyd]

This isn't a paradox, and isn't what the twin paradox refers to. The paradox is that while the twin in the spaceship seems to be moving relative to the twin on earth,  the twin on earth seems to be moving according to the twin in the space ship. According to this both twins should have aged slower than the other twin. But it only seems like a paradox, only the twin in the spaceship undergoes acceleration and deceleration, so what's happening to the twins is not symmetrical.

[edwardfalk]

This isn't the twin paradox. It's just time dilation (special relativity).

The twin paradox is this: from Bert's point of view (we're talking relativity here), the Earth travelled away from him at close to the speed of light, and later came back. So from Bert's point of view, Al should be the one who didn't age very much.

The twin paradox can't be solved with Special Relativity, which deals with unaccelerated reference frames. Einstein's General Relativity, which does handle acceleration, is needed to solve it.

[cuixinshi]

" Al well be alot older then his twin, which made their double dates alot more awkward..."

[fartkerson]

This is only part of the twin paradox. But it's cool to see how the special theory of relativity is used for global positioning. These videos are for people who know very little and it serves them well in accepting a theory most laymen disregard as too close to science fiction, as many people I know personally imagine the world (in such limited ways).

[AlxGamble]

Time and "Age" go hand in hand, or are directly proportional. As you progress through time, you age, and if you slow down time, you would age slower relative to someone else who is experiencing time at a faster rate relative to you. Im not a physics philosopher, just a student looking to learn more, but that is what I gathered from my research of relativity.

[willoughbykrenzteinburg]

The paradox is resolved because the two observers and their respective reference frames are not symmetrical. The reference frames for the stationary observers never changed. They always observed things from their stationary position. If you left in your space ship and traveled some distance, and then returned to the stationary observer, then your reference frame at some point had to have changed. (you were moving away at some point, and toward at another) Your clocks will be the ones behind.

[SiderevsNvncivs]

Let's say that they transmit information as an electromagnetic wave (travelling in the speed of light).

As long as one is accelerating, let's call him A:
B will hear A as you hear music from a passing car, but more-so (what we call Redshift, and Blueshift), and vice-versa (B is playing music, A is the car).
during that phase B is getting older than A.

when there is no acceleration: every twin will hear the other one talking slowly, but they age the same.

[GY]

This is absolutely right, I was just about to post this. But there is actually a solution to the Twin Paradox, and that is why General Relativity was necessary. One of the brothers was constantly shifting his reference frames, while the other stayed in the same one. The acceleration/deceleration would cause time around you to look as if it had sped up significantly, if I recall correctly.

[Narcissist]

@BabyIYours I've seen it and read the description. All it says is that it's impossible for light to arrive to both clocks on the same rod at the same time. I don't see how that's the case - in the moving rod's frame, it is at rest, and therefore the light will reach both clocks at the same time. In the stationary rod's frame, the light will be blueshifted at one end and redshifted the other. However, they arrive at the same time.

[bahrsoap]

Its a paradox in the classical sense, like "they're twins, how can they age different? How is this possible" kind of paradox. Special relativity explains it though.

[Kelavmeister]

You're missing the part about traveling close to the speed of light. The travel involved is where the time dilation becomes more apparent. Time will move slower the faster you go.

[Takiro_Ryo]

As far as I know It is because the gravity actually bends the space-time and does not affect the light directly. Instead the photon follows the bended space. From the photons point of view it is still moving in a straight line. It is an effect described in the theory of general relativity.

[theondono]

The paradox isn't actually about time dilation, but about the fact that every twin is (acording to Galilleo) moving from each other, so both of them would think the other is aging more

[Goproflying]

I'm aware of that, the point I was trying to make was that a conversation between two people travelling at (close) the speed of light wouldn't be possible anyway, so the comment didn't really have any weight.

[Wutwutn]

I wish this had more views than the top viewed videos on youtube, just imagine what society would look like if that were true.

[EduIreland]

It describes, but not explain the paradox. From Al's perspective, Bert is moving, but from Bert's perspective, Al is moving (this is the fundamental aspect of the Relativity Theory). Why does Al gets older? Why not Bert?

[Goproflying]

Doesn't matter, because the spaceship is travelling at almost the same speed as the electromagnetic waves trasmitting the phone conversation. So in other words, the conversation would be very very difficult.

[Anguigen]

I fear this video may not have touched on the entirety of the paradox. It looks only from Al's perspective, from which Bert's clock is moving slower due to his speed. But, due to relativity, from Bert's perspective, Al and the earth are rushing away at near the speed of light, while his spacecraft seems to be constant. Meaning that, from Bert's perspective, Al's clock should run slower.

[libalchris]

Because the frames aren't completely symmetric. Only space twin experiences physical acceleration, changing reference frames. This change of reference frames causes space twin to observe earth twin undergo rapid aging.