Who Experiences 50 Light Years Differently: The Astronaut or Mission Control?

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Discussion Overview

The discussion revolves around the relativistic effects of traveling to a destination 50 light years away at 99.99% the speed of light, specifically focusing on the differing experiences of the astronaut and mission control regarding the passage of time. The scope includes theoretical implications of time dilation, reference frames, and the nature of communication over vast distances.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that the mission control operator would wait the full 50 years while the pilot experiences significantly less time due to time dilation, potentially aging only a few days.
  • Others argue that the time taken for mission control to receive confirmation of the pilot's arrival would exceed 100 years, accounting for the time taken for the radio signal to return to Earth.
  • A participant notes that the perceived travel time for the astronaut would be about 8 and a half months, assuming no significant deceleration is considered.
  • Another participant suggests that if deceleration is factored in, the travel time would be longer, but the astronaut would still age much less than those on Earth.
  • One participant raises the point that the distance of 50 light years is dependent on the reference frame, indicating that in the spaceship's frame, the distance would appear shorter due to length contraction.
  • There is a playful exchange about the assumptions made regarding the mission's nature, including the use of fictional elements like inertial dampeners and magical powers, which adds a humorous layer to the discussion.
  • A later reply emphasizes the importance of clarifying the perspective when discussing distances and speeds in the context of relativity.

Areas of Agreement / Disagreement

Participants express differing views on the implications of time dilation and the effects of acceleration and deceleration. There is no consensus on the specifics of the astronaut's experience versus mission control's experience, and the discussion remains unresolved regarding the nuances of these relativistic effects.

Contextual Notes

Limitations include assumptions about constant speeds, the effects of acceleration and deceleration, and the nature of communication over light years. The discussion does not resolve these complexities.

Kkamann
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Suppose you were traveling from Earth to a destination 50 light years away on a spaceship traveling at 99.99% the speed of light. So who has to wait the full 50 years for the ship to arrive at the destination? The mission control guy sitting in Houston? Or the pilot of the spacecraft ?

I'm not a physicist, nor even work in a science-related field. I'm just a regular dude who finds such things rather fascinating. So please be gentle. I apologize if this question is rediculously rudimentary and it may not seem like rocket science to most of you. But I suppose it is, come to think of it.
 
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The mission control guy waits 50 years, while the pilot takes almost no time. When he return back to Earth he finds 100 years have elapsed, while he may have aged only a few days - depending on how close to the speed of light he was able to go.
 
Kkamann said:
Suppose you were traveling from Earth to a destination 50 light years away on a spaceship traveling at 99.99% the speed of light. So who has to wait the full 50 years for the ship to arrive at the destination? The mission control guy sitting in Houston? Or the pilot of the spacecraft ?

I'm not a physicist, nor even work in a science-related field. I'm just a regular dude who finds such things rather fascinating. So please be gentle. I apologize if this question is rediculously rudimentary and it may not seem like rocket science to most of you. But I suppose it is, come to think of it.
The answer depends on what you mean by waiting. If you are asking how long it will take for the mission control guy to get radio confirmation that you have arrived at your destination, then it will take a little longer than 100 years because it will take you just over 50 years to get there and another 50 years for your radio signal to get back to Earth announcing your arrival. If you mean how long he can assume that it takes you to get there without knowing for sure, then the answer would be just over 50 years.

But from your point of view, because of time dilation, it will take you only 8 and a half months to get there.
 
ghwellsjr said:
But from your point of view, because of time dilation, it will take you only 8 and a half months to get there.

I assume that doesn't count some decent deceleration that will keep the occupants from turning to jello and that WITH such a deceleration (and the similar acceleration on the front end and starting off on the way back), it would take WAY longer
 
phinds said:
I assume that doesn't count some decent deceleration that will keep the occupants from turning to jello and that WITH such a deceleration (and the similar acceleration on the front end and starting off on the way back), it would take WAY longer

With 1g accelerations, it would take the traveler longer, but still MUCH less than 100 years ... he will still be MUCH younger than his friends on Earth when he gets back. For an example with 1g accelerations, see my webpage:

http://home.comcast.net/~mlfasf

Mike Fontenot
 
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Kkamann said:
Suppose you were traveling from Earth to a destination 50 light years away on a spaceship traveling at 99.99% the speed of light. So who has to wait the full 50 years for the ship to arrive at the destination? The mission control guy sitting in Houston? Or the pilot of the spacecraft ?
The distance between Earth and the destination itself depends on the choice of reference frame, I assume it's meant to be 50 light years in the frame where both Earth and the destination are at rest? In that case it will take about 50 years for the spaceship to get there in this frame, but in the ship's frame the distance will be much shorter due to length contraction, so the time is shorter as well.
 
mathman said:
...return back to earth...
phinds said:
...on the way back...
Mike_Fontenot said:
...when he gets back...
Did Kkamann say anything about coming back?
 
It was intended to be just a simple question of whose perpective it is when one says light-year. LOL I didn't feel it necessary to type out all the caveats about subspace communications, round trips, or being turned into chunky salsa when you hit the brakes. But I suppose I should have. After all, we are talking with a bunch of physicists here. Sooo...

It's a one-way kamikaze mission to take out a stationary (relative to Earth) outpost whose inhabitants who have the will and the means to destroy Earth but strangely do not have the ability to detect my ship until it's too late (relative to the outpost, of course). Oh, and my spaceship has inertial dampeners and instant communication stones. And anything else I haven't thought of yet will be handled deftly with my magical powers (And no, I will not simply wipe out the outpost by zapping them with my magical powers. Why? Because I choose to do it this way. Why? Because my god-like powers have made me rather eccentric).

Does that help?:-p
 
Kkamann said:
It was intended to be just a simple question of whose perpective it is when one says light-year. LOL I didn't feel it necessary to type out all the caveats about subspace communications, round trips, or being turned into chunky salsa when you hit the brakes. But I suppose I should have. After all, we are talking with a bunch of physicists here. Sooo...

It's a one-way kamikaze mission to take out a stationary (relative to Earth) outpost whose inhabitants who have the will and the means to destroy Earth but strangely do not have the ability to detect my ship until it's too late (relative to the outpost, of course). Oh, and my spaceship has inertial dampeners and instant communication stones. And anything else I haven't thought of yet will be handled deftly with my magical powers (And no, I will not simply wipe out the outpost by zapping them with my magical powers. Why? Because I choose to do it this way. Why? Because my god-like powers have made me rather eccentric).

Does that help?:-p
As JesseM pointed out, you should state whose perspective it is when you state a distance but since you also stated a speed and there are only two perspectives mentioned, it would be reasonable to assume that you were assigning the distance from the same perspective as the speed was assigned and if it had to be one of those two, then that would make it from the Earth rest frame and my answer previously given in post #3 would apply.
 

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