Author Topic: [Science Question] Speed limit reasoning in a series of books  (Read 1226 times)

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Offline vorpal+5

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[Science Question] Speed limit reasoning in a series of books
« on: November 25, 2017, 01:21:26 AM »
Hey,

In the rather nice series of books from Joshua Dazelle, 'Expansion Wars', there is several time a kind of justification that I don't get. Here it is.

Ships have a maximum speed they can reach, much much below the speed of light (so I'm not talking about the increase in mass by nearing C), past which the thrust of the engines is compensated by ... I don't know what! friction, gravity?

That said, the author seems rather knowledgeable of many physical processes, so I don't get why. If I'm not mistaken, if you apply constant acceleration to a starship/rocket/shuttle you can reach ultimately a speed very close to C. Even at 99% the speed of light, the increase of mass is relatively low.
 

Offline TheDeadlyShoe

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #1 on: November 25, 2017, 03:34:03 AM »
most books that have magical widgets that let their spaceships do cool stuff do put limits on their magical widgets to keep things sane
 

Offline 83athom

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #2 on: December 04, 2017, 07:22:36 AM »
I also have read those books (and the ones from the series before it), and the speed limit is somewhat justified. The speed "limit" is a per-system basis because of the various gravitational bodies effecting lines of travel coupled with the fact that with Newtonian physics any additional force one direction needs to be compensated with force in the other direction to slow down (meaning that they would hit their destination to fast or need a longer time to slow down).
Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.
 

Offline Barkhorn

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #3 on: December 04, 2017, 06:37:45 PM »
Space isn't totally empty.  There's approximately 1-3 hydrogen atoms per cubic meter.  At relativistic speeds, this is non-negligible, so the ship will experience drag much like an aircraft.

Plus, any microscopic dust particle you hit will hit about as hard as an artillery shell.

This isn't the excuse for speed limits Aurora uses.  Aurora's excuse is some extra-dimensional handwavey nonsense that's just meant to make space ships move like oceangoing ships.
 

Offline TheDeadlyShoe

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #4 on: December 04, 2017, 07:21:59 PM »
Aurora is explicitly 'trans newtonian'. Inertia canceling. Normal drag doesn't apply to it.

 

Offline vorpal+5

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #5 on: December 05, 2017, 09:41:06 AM »
Space isn't totally empty.  There's approximately 1-3 hydrogen atoms per cubic meter.  At relativistic speeds, this is non-negligible, so the ship will experience drag much like an aircraft.

Plus, any microscopic dust particle you hit will hit about as hard as an artillery shell.

This isn't the excuse for speed limits Aurora uses.  Aurora's excuse is some extra-dimensional handwavey nonsense that's just meant to make space ships move like oceangoing ships.

Seems logical (the part about Joshua Dazelle books), thanks.

By the way, I know of very few military science fiction books that bother take into account the "any microscopic dust particle you hit will hit about as hard as an artillery shell" part, and this is indeed a huge problem...
 

Offline MarcAFK

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #6 on: December 06, 2017, 06:08:53 AM »
Star trek handwaves it by saying (deflector emitters). Though the ships do suppsoedly have bussard ramscoops which would collect that hydrogen as fuel .... How you could possibly get more energy burning those atoms in a fusion reactor than it would take to give them the same velocity as the ship and prevent any kind of damage is beyond my knowledge.
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Offline Hazard

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #7 on: December 06, 2017, 07:20:21 AM »
Star trek handwaves it by saying (deflector emitters). Though the ships do suppsoedly have bussard ramscoops which would collect that hydrogen as fuel .... How you could possibly get more energy burning those atoms in a fusion reactor than it would take to give them the same velocity as the ship and prevent any kind of damage is beyond my knowledge.

Dilithium.

Seriously, dilitihium in high energy plasma works as a subspace energy siphon in Star Trek, which lets them effectively gain a lot more energy than what their power systems would normally generate to operate their FTL system.
 

Offline TheDeadlyShoe

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #8 on: December 06, 2017, 10:38:50 AM »
all this mis use of handwave irritates me1

the deflector in star trek is not handwavium; it's directly addressing the problem!
 

Offline MarcAFK

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #9 on: December 07, 2017, 08:06:42 AM »
That's still handwaved though. It Emits deflectors? Wtf is a deflector and how do you emit them?
" Why is this godforsaken hellhole worth dying for? "
". . .  We know nothing about them, their language, their history or what they look like.  But we can assume this.  They stand for everything we don't stand for.  Also they told me you guys look like dorks. "
"Stop exploding, you cowards.  "
 

Offline Hazard

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #10 on: December 07, 2017, 08:23:21 AM »
It doesn't emit deflectors.

It emits a powerful and deliberately poorly defined forcefield that protects the ship while traveling from stuff happening in space that's not massive impacts and weapons fire by deflecting them away from the ship.
 

Offline MarcAFK

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #11 on: December 08, 2017, 06:04:29 AM »
Totally sensible. No Handwaving there at all.
" Why is this godforsaken hellhole worth dying for? "
". . .  We know nothing about them, their language, their history or what they look like.  But we can assume this.  They stand for everything we don't stand for.  Also they told me you guys look like dorks. "
"Stop exploding, you cowards.  "
 

Offline TheDeadlyShoe

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #12 on: December 08, 2017, 10:51:00 AM »
'handwaving' is essentially saying eh, dont worry about it.  The way shields work in star trek is handwaved.  Interstellar debris impacts are not; the problem is specifically addressed.  The ships even have Bussard collectors for free hydrogen. 

Similarly, Aurora does not handwave it, because it relies on inertia canceling which implicitly solves the problem.

I honestly cant remember what the expansion wars books say about it, though i have read them...
 

Offline Barkhorn

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #13 on: December 08, 2017, 11:55:02 AM »
I think what people are getting at though, is that their explanation is just kicking the can.    It's like you're saying "Oh they don't handwave that problem away, they use handwavium."
 

Offline TheDeadlyShoe

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Re: [Science Question] Speed limit reasoning in a series of books
« Reply #14 on: December 09, 2017, 03:19:31 AM »
I think that doing that is pushing the term to stretch it far beyond what is useful, though.

Sorry I came off as aggressive in this thread; I had just come off an argument about hard vs soft scifi and the definitions thereof, so i am/was sensitive to relatively minor distinctions, and brought that into my posting :(

Handwaving is a pejorative term and it implies that an explanation is being slapdash, inconsistent, or possibly just nonexistent.  I think its sufficient to establish generally consistent rules and that ships and technology in a setting are generally capable of X but not Y., especially in the television or movie formats; info-dump space is strictly limited both as a practical and acting-practices matter.

Like, what if you turn it around? What would *not* qualify as handwavium for a science fiction setting under a wide standard?  If everything is handwavium, than the term is useless, because it's not actually making any useful distinctions between things.





« Last Edit: December 09, 2017, 03:21:28 AM by TheDeadlyShoe »
 

 

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