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The time dilation aspect in space travel is the most neglected in popular sci-fi. In many of these, there are intricate installations of some sort cryogenic sle

The time dilation aspect in space travel is the most neglected in popular sci-fi. In many of these, there are intricate installations of some sort cryogenic sleep devices because the script authors assume that it takes you 150 years of travel at light speed to get to a place that is 150 light years away.

CodeGlitch 5y ago
Interstellar explores this idea really well. Also see Andy Wiers' new book "Hail Mary", which I can thoroughly recommend. In Hail Mary he doesn't use cryogenics but a different mechanism.
- nahuel0x 5y ago
  Interstellar merged relativity effects with emotional ones, that's a brilliant literary stroke analogous to the ones from the s.f. masters.
eesmith 5y ago
... what? It's been part of SF for decades. The first three that come to mind are: Heinlein's "Time for the Stars", Haldeman's "The Forever War", and Anderson's "Tau Zero". From those titles, a DDG search finds http://sf-encyclopedia.com/entry/relativity http://sf-encyclopedia.com/entry/relativity listing more, also containing the line "Very many sf stories use relativistic time dilation for one-way Time Travel into the future."
- edna314 5y ago
  I'm sure it has been, but I'm mainly talking about popular sci-fi movies. I'm sure you have at least one in mind where they have these 'sleep' devices.
  - simonh 5y ago
    Having sleep pods and such isn't silly if the travel time really is many years.
    - philipswood 5y ago
      Sleep pods are also not silly if you assume your speeds aren't going to be a significant fraction of the speed of light.
      - edna314 5y ago
        I mean yes, but there is a rather specific window where they make sense: at ~1-80% of c. Lower speeds it doesn't make sense to engage in interstellar travel at all, because even travelling 100s of years won't get you anywhere. At higher speeds it doesn't make sense because of time dilation.
        rsynnott 5y ago
        But that's a... pretty important window. There are not-completely-bonkers hypothetical spacecraft designs that could get to, say, 0.2c. There's nothing particularly plausible that could get to 0.99c.
  - eesmith 5y ago
    I'm not much into visual media, so I can only come up with a few examples of 'sleep' devices: Star Trek's "Space Seed" - 200 years in sublight stasis, no mention of speed or distance. Could be 0.5c for all we know. 100 ly at Enterprise's warp 6 cruising speed would take about 4 months, which seems not unreasonable. The movie "Alien" - stasis, but seemingly with FTL given the times and distances involved. (https://avp.fandom.com/wiki/LV-223 https://avp.fandom.com/wiki/LV-223 says it was a 2 year voyage to the moon LV-223 in Prometheus.) The TV series "Red Dwarf" - sublight, though it did break the light barrier once. Science in general is only relevant for comedic effect. https://www.ganymede.tv/2004/04/the-science-of-red-dwarf/ https://www.ganymede.tv/2004/04/the-science-of-red-dwarf/ . None of these seem to be characterized as "it takes you 150 years of travel at light speed to get to a place that is 150 light years away". Which one am I missing?
    - edna314 5y ago
      What came to my mind immediately was 'Passengers'. But, reading up the plot on Wikipedia, it is possible that it never actually was mentioned how far away the destination was or how fast they were going. So, maybe it wasn't a misconception on the sci-fi side, but on my side. For sure, any light speed travel shouldn't take any time and infinite amount of time should pass for the rest of the universe.
      - eesmith 5y ago
        From Wikipedia, 60 light years and "a journey lasting 120 years". It doesn't say if that's 120 ship years or Earth years. I'll assume ship years as that makes the most sense in context. Assuming constant acceleration to the 1/2-way point, flip, deceleration, and using http://www.projectrho.com/public_html/rocket/slowerlight3.php http://www.projectrho.com/public_html/rocket/slowerlight3.ph... : T = (c/a) * ArcCosh[a*d/(c^2) + 1] (given acceleration and distance) 60 years = (c / a) * arccos(a * 30 ly / (c^2) + 1) 1893456000.0 = (3E8/a) * arccos(a * 3.15576 + 1) Using Wolfram Alpha to solve - https://www.wolframalpha.com/input/?i=1893456000.0+%3D+%283E8%2Fx%29+*+arccosh%28x+*+3.15576+%2B+1%29 https://www.wolframalpha.com/input/?i=1893456000.0+%3D+%283E... a = 0.14748 m/s^2 or about 1.5% g Time elapsed on Earth is only a bit longer than ship time: t = (c/a) * Sinh[a*T/c] = 1.15 * ship time ("proper time") Final velocity at flip is: v = c * Tanh[a*T/c] = 0.73 * speed of light
- akvadrako 5y ago
  There are very few sci-fi movies or books where relativity is important and they treat it seriously. Tau Zero is one, I'm not sure about Time for the Stars, but Forever War does have FTL. I created a list of all these works I could find a few years ago. Here is one link: https://tvtropes.org/pmwiki/discussion.php?id=l6q90mvssgscsj5arqe8umjb https://tvtropes.org/pmwiki/discussion.php?id=l6q90mvssgscsj... I think this is a complete list of the films and tv series: - The Star Lost - Pandorum - Passengers (2016)
  - eesmith 5y ago
    Time for the Stars has FTL at the end. (Physical FTL, that is. Telepathic FTL exists at the beginning.) But it's otherwise it's deliberately structured around the twin paradox - the main character is even a twin. Indeed, while I remembered the importance of time dialation in Forever War , I didn't remember the FTL travel between collapsars.
  - rsynnott 5y ago
    Virtually all of Larry Niven's novels that don't have FTL touch on this. Also shows up in most of Alastair Reynolds' novels, and in the Three Body Problem series.
    - akvadrako 5y ago
      I know of Niven's "The Legacy of Heorot", but it only takes place on one planet. Most of Alastair Reynold's novels have FTL - I only know of one that counts, which is Pushing Ice. The 3-body problem has FTL also.
      - rsynnott 5y ago
        > I know of Niven's "The Legacy of Heorot", but it only takes place on one planet. The chronologically earlier novels in his Known Space universe (the Ringworld one) are mostly around near-c Bussard ramjets. > Most of Alastair Reynold's novels have FTL Hmm, wait, which ones? Only one I can think of is House of Suns, in a very restricted manner. > The 3-body problem has FTL also. It has FTL communications, but not travel.
deleted 5y ago
[deleted]
simonh 5y ago
That's a very basic error, but I can't offhand remember coming across a story where the author made this mistake. After all, if the ship's top speed is even modestly below light speed the journey really could take many decades. Can you give an example?
- edna314 5y ago
  I wasn't referring to the author in the article, but rather an unspecified collection of 'popular' SciFi, where this aspect is not explained. It is true that, even if you reach speeds of 0.5c you only get a ~15% time dilation.
  - TeMPOraL 5y ago
    Which is why most popular sci-fi franchises end up with velocity caps, justified either in-universe or out-of-universe. E.g. Star Trek sublight propulsion (impulse engine) has been established indirectly and through "word of God" to work with speeds up to ~1/3 c, which is not enough for relativistic effects to cause a big impact. The issue is conveniently omitted, because why travel fast through "normal space" when you have easy access to warp drive / jump drive / hyperdrive / wormholes, that gives you FTL and happens to drop you out into a convenient reference frame? And all the interesting action happens around planets anyway. This omission makes it easy for the writers to introduce relativity as a nerdy plot point. For example, StarGate: Atlantis had an episode with a ship traveling absurdly close to the speed of light, which was devised as a convenient way to introduce characters that should've been dead for many thousands of years.
jobigoud 5y ago
> the script authors assume that it takes you 150 years of travel at light speed to get to a place that is 150 light years away Or maybe they know you wouldn't travel at light speed in the first place.

CodeGlitch 5y ago

Interstellar explores this idea really well. Also see Andy Wiers' new book "Hail Mary", which I can thoroughly recommend. In Hail Mary he doesn't use cryogenics but a different mechanism.

nahuel0x 5y ago
Interstellar merged relativity effects with emotional ones, that's a brilliant literary stroke analogous to the ones from the s.f. masters.

eesmith 5y ago

... what? It's been part of SF for decades. The first three that come to mind are: Heinlein's "Time for the Stars", Haldeman's "The Forever War", and Anderson's "Tau Zero". From those titles, a DDG search finds http://sf-encyclopedia.com/entry/relativity http://sf-encyclopedia.com/entry/relativity listing more, also containing the line "Very many sf stories use relativistic time dilation for one-way Time Travel into the future."

edna314 5y ago
I'm sure it has been, but I'm mainly talking about popular sci-fi movies. I'm sure you have at least one in mind where they have these 'sleep' devices.
- simonh 5y ago
  Having sleep pods and such isn't silly if the travel time really is many years.
  - philipswood 5y ago
    Sleep pods are also not silly if you assume your speeds aren't going to be a significant fraction of the speed of light.
    - edna314 5y ago
      I mean yes, but there is a rather specific window where they make sense: at ~1-80% of c. Lower speeds it doesn't make sense to engage in interstellar travel at all, because even travelling 100s of years won't get you anywhere. At higher speeds it doesn't make sense because of time dilation.
      - rsynnott 5y ago
        But that's a... pretty important window. There are not-completely-bonkers hypothetical spacecraft designs that could get to, say, 0.2c. There's nothing particularly plausible that could get to 0.99c.
- eesmith 5y ago
  I'm not much into visual media, so I can only come up with a few examples of 'sleep' devices: Star Trek's "Space Seed" - 200 years in sublight stasis, no mention of speed or distance. Could be 0.5c for all we know. 100 ly at Enterprise's warp 6 cruising speed would take about 4 months, which seems not unreasonable. The movie "Alien" - stasis, but seemingly with FTL given the times and distances involved. (https://avp.fandom.com/wiki/LV-223 https://avp.fandom.com/wiki/LV-223 says it was a 2 year voyage to the moon LV-223 in Prometheus.) The TV series "Red Dwarf" - sublight, though it did break the light barrier once. Science in general is only relevant for comedic effect. https://www.ganymede.tv/2004/04/the-science-of-red-dwarf/ https://www.ganymede.tv/2004/04/the-science-of-red-dwarf/ . None of these seem to be characterized as "it takes you 150 years of travel at light speed to get to a place that is 150 light years away". Which one am I missing?
  - edna314 5y ago
    What came to my mind immediately was 'Passengers'. But, reading up the plot on Wikipedia, it is possible that it never actually was mentioned how far away the destination was or how fast they were going. So, maybe it wasn't a misconception on the sci-fi side, but on my side. For sure, any light speed travel shouldn't take any time and infinite amount of time should pass for the rest of the universe.
    - eesmith 5y ago
      From Wikipedia, 60 light years and "a journey lasting 120 years". It doesn't say if that's 120 ship years or Earth years. I'll assume ship years as that makes the most sense in context. Assuming constant acceleration to the 1/2-way point, flip, deceleration, and using http://www.projectrho.com/public_html/rocket/slowerlight3.php http://www.projectrho.com/public_html/rocket/slowerlight3.ph... : T = (c/a) * ArcCosh[a*d/(c^2) + 1] (given acceleration and distance) 60 years = (c / a) * arccos(a * 30 ly / (c^2) + 1) 1893456000.0 = (3E8/a) * arccos(a * 3.15576 + 1) Using Wolfram Alpha to solve - https://www.wolframalpha.com/input/?i=1893456000.0+%3D+%283E8%2Fx%29+*+arccosh%28x+*+3.15576+%2B+1%29 https://www.wolframalpha.com/input/?i=1893456000.0+%3D+%283E... a = 0.14748 m/s^2 or about 1.5% g Time elapsed on Earth is only a bit longer than ship time: t = (c/a) * Sinh[a*T/c] = 1.15 * ship time ("proper time") Final velocity at flip is: v = c * Tanh[a*T/c] = 0.73 * speed of light
akvadrako 5y ago
There are very few sci-fi movies or books where relativity is important and they treat it seriously. Tau Zero is one, I'm not sure about Time for the Stars, but Forever War does have FTL. I created a list of all these works I could find a few years ago. Here is one link: https://tvtropes.org/pmwiki/discussion.php?id=l6q90mvssgscsj5arqe8umjb https://tvtropes.org/pmwiki/discussion.php?id=l6q90mvssgscsj... I think this is a complete list of the films and tv series: - The Star Lost - Pandorum - Passengers (2016)
- eesmith 5y ago
  Time for the Stars has FTL at the end. (Physical FTL, that is. Telepathic FTL exists at the beginning.) But it's otherwise it's deliberately structured around the twin paradox - the main character is even a twin. Indeed, while I remembered the importance of time dialation in Forever War , I didn't remember the FTL travel between collapsars.
- rsynnott 5y ago
  Virtually all of Larry Niven's novels that don't have FTL touch on this. Also shows up in most of Alastair Reynolds' novels, and in the Three Body Problem series.
  - akvadrako 5y ago
    I know of Niven's "The Legacy of Heorot", but it only takes place on one planet. Most of Alastair Reynold's novels have FTL - I only know of one that counts, which is Pushing Ice. The 3-body problem has FTL also.
    - rsynnott 5y ago
      > I know of Niven's "The Legacy of Heorot", but it only takes place on one planet. The chronologically earlier novels in his Known Space universe (the Ringworld one) are mostly around near-c Bussard ramjets. > Most of Alastair Reynold's novels have FTL Hmm, wait, which ones? Only one I can think of is House of Suns, in a very restricted manner. > The 3-body problem has FTL also. It has FTL communications, but not travel.

deleted 5y ago

[deleted]

simonh 5y ago

That's a very basic error, but I can't offhand remember coming across a story where the author made this mistake. After all, if the ship's top speed is even modestly below light speed the journey really could take many decades. Can you give an example?

edna314 5y ago
I wasn't referring to the author in the article, but rather an unspecified collection of 'popular' SciFi, where this aspect is not explained. It is true that, even if you reach speeds of 0.5c you only get a ~15% time dilation.
- TeMPOraL 5y ago
  Which is why most popular sci-fi franchises end up with velocity caps, justified either in-universe or out-of-universe. E.g. Star Trek sublight propulsion (impulse engine) has been established indirectly and through "word of God" to work with speeds up to ~1/3 c, which is not enough for relativistic effects to cause a big impact. The issue is conveniently omitted, because why travel fast through "normal space" when you have easy access to warp drive / jump drive / hyperdrive / wormholes, that gives you FTL and happens to drop you out into a convenient reference frame? And all the interesting action happens around planets anyway. This omission makes it easy for the writers to introduce relativity as a nerdy plot point. For example, StarGate: Atlantis had an episode with a ship traveling absurdly close to the speed of light, which was devised as a convenient way to introduce characters that should've been dead for many thousands of years.

jobigoud 5y ago

> the script authors assume that it takes you 150 years of travel at light speed to get to a place that is 150 light years away Or maybe they know you wouldn't travel at light speed in the first place.