Bussard Ramjet is a sublight drive. Apparently it would take more energy collecting the fuel than it obtains from the fuel.
(draws alignment grid)
I mean, really, science fiction and speculative fiction authors have taken a number of approaches. (P.S. plus “one unbelievable thing” rule-- a couple items from the middle or bottom rows are one thing, but too many from the bottom row bug me.)
LG: Uses existing physics, might work. (Some of the hardest of hard sf.)
NG: Uses something beyond existing physics, might work. (The “Power of the Sun” for the Nautilus in 20,000 leagues. Being generous, the various jump, hyperspace, and warp drives.)
XG: Uses something outside physics, might work. (Being generous, psionic teleportation in an idealist universe.)
skipping neutral row…
LE: Uses existing physics, already known not to work. (The shock absorbers for the lunar shell in Verne’s moon stories. He admitted the problem in a footnote.)
NE: Uses something beyond existing physics, already known not to work. (Cavorite, Liftwood, etc. break existing physics.)
XE: Uses something outside physics, can’t work. (I’m inclined to put most time travel stories in this category.)
I’m currently reading a webserial called The Last Angel: Ascension (the sequel of the original The Last Angel).
The technology doesn’t really bother me: they have a NG novum (“breach cores,” or basically jump drives), and a LG novum (strong AI).
What does bother me (and what might fit somewhere the “Neutral” row in your alignment chart) is the xenobiology. Which is basically just normal Terran biology, regardless of the species. Alien species are described as “mammalian” or “reptilian” - and I’ve confirmed with the author that he pretty much means that those species would be taxonomically classified the same way on Earth. It doesn’t break any laws of physics, but the sheer statistical impossibility of it… I mean, convergent evolution in similar environments is one thing, but on different planets with different atmospheres and different gravities and different geologies and histories and… Gah. Just gah.
Hard to say. If the FTL methods, e.g., warp drive, are possible, the maths pretty much demand that time travel be possible as well. Either both are impossible (entirely possible), both are possible (which opens up a real can of worms), or there are distinct, but still unknown, limits on how warps, wormholes, etc. can work which preserve causality (also possible).
For example, there’s a series by Walter Jon Williams called “Dread Empire’s Fall,” where there are wormholes to the past and future… but the other end of those wormholes are more light-years away than the number of years it takes you back/forward in time. So, you could send a message about treachery back 100 years into the past to give to yourself, but, by the time you’ll receive the message, you’ve already sent it.
…or a multiverse interpretation of quantum mechanics proves factual and affects wormhole physics, in which case tunneling through space-time to shoot your granddad has no effect on you, 'cause he warn’t your granddad - granddad was back in a different universe.
Or the universe forces self-consistency, in which case you can get your grandfather nuked, then comfort your grandmother on her loss and become your own grandfather (which is nothing that a significantly well-adjusted family can’t deal with).
The term “speculative fiction” was invented (by 1960s new wave authors) to avoid the dreaded “science” word, in stories that would otherwise be lumped in with science fiction by fans et al. So one could say that science fiction (with actual science, hard or soft), fantasy, alternate history or future histories (with no differences in technology), time travel, etc. are all different subsets of speculative fiction. Of course, any fiction that is made up would come under that umbrella too, so maybe the term is useless.
I still think it’s the best term for “if we have that one unbelievable thing, then…”
So hard science fiction, social science fiction, magical realism, etc. can all be “speculative fiction,” while allegory and rule-of-cool fiction are something else. Of course there’s a lot of middle ground: Middle Earth, Lewis’s Space Stories, Lensman, Star Wars, The Dark Wife, etc.
Carlo Rovelli has some strange things to say about time.
The Order of Time Carlo Rovelli Allen Lane (2018)
According to theoretical physicist Carlo Rovelli, time is an illusion: our naive perception of its flow doesn’t correspond to physical reality. Indeed, as Rovelli argues in The Order of Time , much more is illusory, including Isaac Newton’s picture of a universally ticking clock. Even Albert Einstein’s relativistic space-time — an elastic manifold that contorts so that local times differ depending on one’s relative speed or proximity to a mass — is just an effective simplification.
So what does Rovelli think is really going on? He posits that reality is just a complex network of events onto which we project sequences of past, present and future. The whole Universe obeys the laws of quantum mechanics and thermodynamics, out of which time emerges.
I envision a new literary journal devoted not to critiques of character development and plot, but whether the basic science was understood by the author.
I don’t think it was unreasable for authors to use current physics and engineering proposals. It was current from 1960 to about 1978, with suggestions that some versions may be viable using other types of fusion, or in nebulae.
The Ringworld Engineers and later Ringworld and Known Space stories stuck with Bussard rams afterwards.
I don’t know about sticking with existing lore or retconning it.
Apparently Star Trek introduces ramscoops in warp… but I thought warp was supposed to skip over space… so where do the ramscoops collect the hydrogen from…?
I do think that was unreasonable.
Terran Trade Authority also noted that one of the Proximan ships used hydrogen scoops for increased range. I don’t remember how it addressed ftl.
Well, assuming the Star Trek warp metric is pretty much the same as the Alcubierre metric, the ship is riding in a moving bubble of spacetime. That’s to say that there is a moving compression and expansion of spacetime in which the ship remains centered, in the flat area between the two. Now I’d imagine that the bubble may carry along with it some hydrogen, but the leading edge is, for all intents and purposes, a black hole (or, assuming that such a drive becomes practical, more likely a Kugelblitz), and I’d imagine that is likely to swallow all hydrogen in its path.
Of course, we all know that the Enterprise really runs on handwavium…
