4 ms·

Reaching relativistic speeds in minutes to hours and covering interstellar distances in days to weeks as proposed in the abstract seem to not be compatible - wo

by smoyer 5y ago

Reaching relativistic speeds in minutes to hours and covering interstellar distances in days to weeks as proposed in the abstract seem to not be compatible - wouldn't a relativistic speed mean we'd need 4ish years to reach another star?

thfuran 5y ago
That depends whose clock you're using.
netgusto 5y ago
The durations are expressed in ‘ship time’, ie the perceived duration from the pov of the ship. This is explicited further in the document.
- kmote00 5y ago
  Off topic comment: I'm pretty sure "explicited" is not a real word, but you've convinced me that it ought to be. Perfectly clear what you meant. Can somebody add this to the dictionary, please?
  - jointpdf 5y ago
    They probably meant: explicate — to give a detailed explanation of https://www.merriam-webster.com/dictionary/explicate https://www.merriam-webster.com/dictionary/explicate It seems like a relatively newer word in its usage: https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&corpus=26&smoothing=7&case_insensitive=on&content=explicate&direct_url=t4%3B%2Cexplicate%3B%2Cc0%3B%2Cs0%3B%3Bexplicate%3B%2Cc0%3B%3BExplicate%3B%2Cc0 https://books.google.com/ngrams/graph?year_start=1800&year_e...
    - aordano 5y ago
      I read it more as "made explicit" rather than "explained"
  - netgusto 5y ago
    ah! TIL, I always thought it was a real word.
shkkmo 5y ago
From the body of the paper: > Such a craft accelerating at a constant 1000g for half of the trip and decelerating at the same rate for the remaining half would reach Proxima Centuri within 5 days’ ship time due to the fact that it would have been traveling at relativistic speeds for most of the trip (Figure 7B). However, for those of us on Earth, or anyone on Proxima Centuri b, the trip would take over four years.
Sharlin 5y ago
The important part is the last two words, proper time, which is the time measured by a clock travelling along some given world line [1]. In this case, the world line of the hypothetical interstellar craft. [1] https://en.wikipedia.org/wiki/Proper_time https://en.wikipedia.org/wiki/Proper_time

by smoyer 5y ago

thfuran 5y ago

That depends whose clock you're using.

netgusto 5y ago

The durations are expressed in ‘ship time’, ie the perceived duration from the pov of the ship. This is explicited further in the document.

kmote00 5y ago
Off topic comment: I'm pretty sure "explicited" is not a real word, but you've convinced me that it ought to be. Perfectly clear what you meant. Can somebody add this to the dictionary, please?
- jointpdf 5y ago
  They probably meant: explicate — to give a detailed explanation of https://www.merriam-webster.com/dictionary/explicate https://www.merriam-webster.com/dictionary/explicate It seems like a relatively newer word in its usage: https://books.google.com/ngrams/graph?year_start=1800&year_end=2019&corpus=26&smoothing=7&case_insensitive=on&content=explicate&direct_url=t4%3B%2Cexplicate%3B%2Cc0%3B%2Cs0%3B%3Bexplicate%3B%2Cc0%3B%3BExplicate%3B%2Cc0 https://books.google.com/ngrams/graph?year_start=1800&year_e...
  - aordano 5y ago
    I read it more as "made explicit" rather than "explained"
- netgusto 5y ago
  ah! TIL, I always thought it was a real word.

shkkmo 5y ago

From the body of the paper: > Such a craft accelerating at a constant 1000g for half of the trip and decelerating at the same rate for the remaining half would reach Proxima Centuri within 5 days’ ship time due to the fact that it would have been traveling at relativistic speeds for most of the trip (Figure 7B). However, for those of us on Earth, or anyone on Proxima Centuri b, the trip would take over four years.

Sharlin 5y ago

The important part is the last two words, proper time, which is the time measured by a clock travelling along some given world line [1]. In this case, the world line of the hypothetical interstellar craft. [1] https://en.wikipedia.org/wiki/Proper_time https://en.wikipedia.org/wiki/Proper_time