Comment by javajosh | Hacker News Reader

Comment by javajosh | Hacker News Reader

Sadly, I've come to believe that any story with FTL in it must be classified as fantasy. I might be willing to accept natural wormhole travel. Even with generation ships, authors vastly underestimate the difficulties of traveling interstellar distances. When authors posit intergalactic travel, forget about it! Galaxies might as well be pocket universes because they don't interact. (Unless they collide, which will happen with the Milky Way and Andromeda in about 4.5 billion years. Oh man if we can make it that long and have even slow interstellar travel, what an opportunity for exploration!)

But yeah, thank god most of science fiction is actually fantasy because if any of those things were possible, they'd immediately be used to destroy planets. Ships going FTL could be collided into a planet. Teleportation and easily accessed anti-matter could be used to annihilate cities - or planets. Most authors don't even bother building in reasons why that can't happen, its just that no-one thinks of doing it.

I think the limits of the real world are quite fascinating. It's almost like reality was designed to support a huge array of civilizations that cannot interfere with each other. Interstellar travel is so hard that any civ capable of it is going to be capable of executing technologically advanced projects over centuries or millenia, and I daresay such a civ is not doing it for conquest, but to discover and explore. If the urge is militaristic, then such a civ would turn on itself long before the project succeeds. There's a kind of poetry to it.

Most scifi I've read with FTL usually has some explanation that isn't pure fantasy. For example, I just finished reading A Fire Upon the Deep[1] by Vernor Vinge, and the in-universe explanation for FTL in the novel is that different regions of our galaxy effectively have different laws of physics, which is (admittedly somewhat handwavingly) due to the density of the interstellar medium.

Sure, FTL travel is never grounded in our understanding of physics and the universe, but do you really think our understanding is anywhere near complete?

[1] https://en.wikipedia.org/wiki/A_Fire_Upon_the_Deep

Deepness in the Sky is good too, avoid Children of the Sky

Love that book, but it's fantasy. It's a cool idea that is impossible to rule out without literally going to every part of the universe and doing experiments there. But that's impossible, so it's unfalsifiable. In fact, you could make the same claim about Earth. We aren't going to do every experiment at every place on and in Earth.

First, falsifiability does not a theory make (that's Popper's view, and the ability to test doesn't always include the possibility of falsification). Second, science fiction stories aren't theories, and aren't actually science. They don't have to pose a testable theory.

I don't have anywhere near the physics chops to debate this in detail, but the usual contention WRT FTL is that our understanding of physics actively precludes the possibility of FTL. Winchell Chung's Atomic Rockets website gives a good account of the basic argument here: https://www.projectrho.com/public_html/rocket/fasterlight.ph...

> Most scifi I've read with FTL usually has some explanation that isn't pure fantasy.

My favourites are from Futurama:

1. Scientists increased the speed of light in the year 2208.

2. "The [Dark Matter Engines] don't move the ship at all. The ship stays where it is and the engines move the universe around it."

> Most authors don't even bother building in reasons why that can't happen, its just that no-one thinks of doing it.

Is it really necessary to spell out that a civilization capable of building a FTL starship is also capable of building a sufficient defensive technology?

> I daresay such a civ is not doing it for conquest, but to discover and explore. If the urge is militaristic, then such a civ would turn on itself long before the project succeeds.

I think this is much more complex. Consider a civilization so advanced that this is children's toys for them - and then that civilization falls. Then, on the scraps of it, a new imperialistic faction is built and they go for the conquest; they don't even need to understand the magic that powers their warships. I recommend you to read the full Foundation series in chronological order.

Kind of like tribalism on earth prevented empires?

I've read everything. I probably read the Foundation series before you were born (assuming you're 20-something). In fact, Asimov certainly knew that FTL was fraught - but he was writing for a living, and FTL was in vogue and he used the hyperspace version of it. It's unfortunate - I would have liked to see more grounded SF from him

Well the issue remains the same with Bussard ramjets. It's just simpler to make so the whole scenario is more likely (though still very unlikely, ofc).

"Is it really necessary to spell out that a civilization capable of building a FTL starship is also capable of building a sufficient defensive technology?"

We have had ICBMs for a long time, yet no sufficient defensive technology as of yet.

Beyond the fact that using them would lead to MAD, that is.

I think FTL is reasonable cop-out. So just existence alone does not make something fantasy. At least if the implications are properly explored and things are consistent.

Neither Star Wars or Star Trek do things well. Some other material does things reasonably well explained and thus actually are on Fiction side.

Hardest possible take does not really leave too much room to go around. Some expectations make more interesting stories and explorations.

> Ships going FTL could be collided into a planet.

Or it will pass through a planet like neutrino. How you know which FTL method will actually work?

I know exactly which FTL method will work.

But Low Energy FTL travel is far greener for our Galaxy than HE FTL. With HE FTL, just one mistake can born new supernova. Moreover, it requires year of whole star energy for singe travel. 90% of stars turned dark just because of that. I will call you "Dark Lord" from now.

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