Can Light Speed Travel Change Our Perception of Time at Proxima Centauri?

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Discussion Overview

The discussion revolves around the implications of traveling at or near light speed to Proxima Centauri, specifically focusing on the perception of time for both the crew and observers on Earth. Participants explore theoretical scenarios regarding time dilation, aging, and the visibility of the crew's departure and return.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question the feasibility of traveling at light speed, suggesting that it is impossible, while others propose discussing travel at nearly light speed (e.g., 0.9999999 c).
  • There is a suggestion that if a crew travels just under light speed, the trip could take slightly more than 8 years from Earth's perspective, with specific times discussed for departure and arrival.
  • One participant emphasizes that the crew's experience of time would differ significantly from that of observers on Earth, potentially only feeling a few minutes of travel time due to time dilation effects.
  • Another participant notes that the aging process of the crew would be significantly less than that of people on Earth during the journey, raising questions about the implications of time dilation.
  • There is a clarification regarding the relationship between the time experienced by the crew and the time perceived by observers on Earth, with some participants discussing the nuances of how clocks and biological aging are affected differently.

Areas of Agreement / Disagreement

Participants generally agree that traveling at light speed is impossible, but there is no consensus on the implications of traveling at near-light speed, particularly regarding the perception of time and aging. Multiple competing views remain on how to interpret the effects of time dilation.

Contextual Notes

The discussion includes assumptions about the nature of time and aging, as well as the theoretical framework of special relativity, which are not fully resolved. The specific conditions of the journey and the effects of relativistic speeds on biological processes are also not conclusively addressed.

bluemanta9
I am a physics "layman", so please forgive me if these questions seem basic.

Let's say we can travel at light speed, we send a crew to Proxima Centauri, & it's exactly 4 light years away. They explore for exactly one day, then return.

1. Since it takes 4 years for light to reach it & 4 years to return it, would we not see our crew arrive for 8 years? Also...

2. Would we see them both leaving Proxima Centari & arriving back at Earth at the same time on the next day?
 
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bluemanta9 said:
I am a physics "layman", so please forgive me if these questions seem basic.

Let's say we can travel at light speed
No, let's not, since it is impossible.
 
bluemanta9 said:
Let's say we can travel at light speed,
Well, it is not possible even in theory to travel at light speed. However, we could travel at nearly light speed (say 0.9999999 c). Would you accept an answer to that slightly modified question?
 
Dale said:
Well, it is not possible even in theory to travel at light speed. However, we could travel at nearly light speed (say 0.9999999 c). Would you accept an answer to that slightly modified question?

Sure.
 
Ok, so to keep things simple, let's say that they travel just under light speed so that the 4 light year trip takes 4 years plus 1 minute.

bluemanta9 said:
1. Since it takes 4 years for light to reach it & 4 years to return it, would we not see our crew arrive for 8 years? Also...
Yes. They would arrive in 4 years and 1 minute, so we would see them arrive after 8 years and 1 minute.
bluemanta9 said:
2. Would we see them both leaving Proxima Centari & arriving back at Earth at the same time on the next day?
Almost. We would see them leave PC at 8 years 1 day and 1 minute, and then we would see them arrive at 8years 1 day and 2 minutes
 
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Dale said:
Ok, so to keep things simple, let's say that they travel just under light speed so that the 4 light year trip takes 4 years plus 1 minute.

Yes. They would arrive in 4 years and 1 minute, so we would see them arrive after 8 years and 1 minute.Almost. We would see them leave PC at 8 years 1 day and 1 minute, and then we would see them arrive at 8years 1 day and 2 minutes

Thank you! :-)
 
Someone needs to point out that, as far as the ship's crew (their body cells) and all the ship's clocks are concerned, their whole journey may have taken only a few minutes. They wouldn't have aged more than that.
The given example is too extreme to contemplate but, given a suitable drive and enough fuel to accomplish a 'very fast' journey, we could observe a significant difference in the ageing process for the ship's crew and the rest of us on Earth over the (more realistic) ten Earth years that they were away for.
 
sophiecentaur said:
Someone needs to point out that, as far as the ship's crew (their body cells) and all the ship's clocks are concerned, their whole journey may have taken only a few minutes.
Dale did, 2min -1min =1min
 
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nitsuj said:
Dale did, 2min -1min =1min
Yes. I read it but my point was about the fact that they would actually experience the changed time. People often think (wrongly) that the way the clock works is not the same as the way their brain and other cells would age. (I think my point was a valid addition.)
 

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