Relativity Expert on Startalk Podcast: Interstellar & Near Light Travel

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Discussion Overview

The discussion revolves around the implications of near-light-speed travel, particularly in the context of a hypothetical journey to a location 1,000 light years away. Participants explore the effects of relativistic speeds on time experienced by travelers versus stationary observers on Earth, referencing concepts from the Startalk podcast and the movie Interstellar.

Discussion Character

  • Exploratory
  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant expresses frustration with discussions that focus solely on stationary observers, arguing that travelers on a spaceship would experience significantly less time than the 1,000 years indicated for Earth observers.
  • Another participant agrees, suggesting that if travelers do not intend to return to Earth, the time experienced by those on the spaceship becomes irrelevant.
  • A participant questions how long the journey would actually take for those on the rocket, indicating a desire for more specific calculations.
  • Responses indicate that the travel time depends on the speed achieved, with one participant suggesting a uniform acceleration of 1 G to 0.99c, leading to various estimates of travel time.
  • Calculations provided suggest that at 0.99c, the journey could take about 1000/7 years, while a speed of 0.9999999c might reduce the travel time to approximately 6 months.
  • Another participant shares a relativistic space travel calculator, which estimates that a 1,000 light year journey at 1 G acceleration would take the crew about 13 years.

Areas of Agreement / Disagreement

Participants generally agree that the time experienced by travelers differs from that experienced by stationary observers, but specific calculations and estimates vary. There is no consensus on the exact travel time, as it depends on the speed achieved and the assumptions made about acceleration.

Contextual Notes

Limitations include the assumptions made about acceleration and the specific speeds discussed, which may not account for all variables in relativistic travel.

SBNY444
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I really hate, and also not fully understand it, when people talk about near light travel and they only mention about the stationary observers (people on earth). I forget her name but the relativity expert on the Startalk podcast about the movie interstellar, along with Neil, said that if you travel near the speed of light to a distant location say 1,000 light years away from earth, it's not feasible because it will take you 1,000 years. This is true only relative to the observers and is only half the story! The person or people on the spaceship going near the speed of light will get there significantly sooner than 1,000 years travel time. So if you can imagine a far fetch scenario where we all needed to leave Earth and somehow NASA got funding for 1 million spacecraft that could hold 6,000 people (which is a seat for all on Earth give or take) and the spacecraft all go near the speed of light and we all left at the same time then the 1,000 light year value is not relevant to the journey. I didn't do the math but we would get to our "1,000 light year away" location in say a few years if that, right? Please help! this is making me loose sleep :)
 
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SBNY444 said:
I didn't do the math but we would get to our "1,000 light year away" location in say a few years if that, right?
Yes. If you don't care about coming back to meet old friends, the time passed on Earth becomes irrelevant to you.
 
Yes, i don't care about going back to earth. It's in ruins and everyone on Earth has launched with me. Any idea how long it would actually take for the people on the rocket?
 
That depends on how fast you go. Have you got inertial dampers so you could survive high-g accelerations for a long time ( like 20 minutes) ?
 
let's not get technical and stray from the actual question. Assume a uniform 1 G acceleration to 0.99c.
 
Last edited:
Handy dandy relativistic space travel calculator: http://nathangeffen.webfactional.com/spacetravel/spacetravel.php

For a 1000 LY journey accelerating at 1 g, it would take the crew 13 years.
 
Last edited:
wow, these tools are sweet. Thanks all!
 

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