Oct 202013
 

A while back, I wrote a post about aesthetics vs. practicality in designing science fiction spaceships, which also extends to any sort of speculative design.

Recently, a discussion exploded on the same board over an initially small misunderstanding that went rampant really fast. You can read about it here, if you care to (it spans three pages). The short version is that I pointed out some conceptual flaws in this particular artist’s explanation for how the FTL1 drive works. After some back and forth, wherein the artist got increasingly hostile to having their idea poked at, they fired off a massive post/rant. I almost gave into the temptation to respond to it, but that little voice in the back of my head said, “Dude, get real. They’re not listening. They’re not going to listen. They’ve got too much baggage going into this for your points to get through. Just leave it.” So I did. I apologized for upsetting them, restated that my only goal was to share information/correct misconceptions, complimented them on their model, and wished them well on their worldbuilding. Then I bowed out.

This all played out from 10/17 to 10/18. Yet I’m still thinking about it. I don’t feel any better now than I did when it all played out; if anything, I might be feeling even worse. Enumerating all of the reasons why would take too long, but there’s one point that I wanted to home in on because I see it everywhere and it needs to die.

in case nobody told you…the FI in sci fi means Fiction!!! The concept of this system is based on an assumed understanding of physics that guess what? We don’t and may never have

Wrong. Wrong, wrong, wrong, wrong, wrong. The fiction in science fiction serves the exact same role as it does in fantasy fictioncrime fiction, literary fiction, romance fiction, and every other stripe of fiction out there: it serves to indicate that the story, characters, and setting are made-up. Period. Done.

The science in science fiction clarifies the broader genre: these are made-up stories, characters, and settings where science is the driver behind what is different. New technologies, alien species, and so on; just as magic–the truly fantastic–drives fantasy fiction. There can absolutely be overlap: technological magic, magical technology, whatever you like. But these are the distinguishing features of the genres that give them a unique place.

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  1. That’s “faster than light”…but if you’re not familiar with that term, then most of this post is going to seem even more ridiculous to you. []
Sep 182012
 

A recent article posted by Gizmodo, titled “NASA Starts Work on Real Life Star Trek Warp Drive”, has stirred up a bit of excitement, and rightly so. Unfortunately, as with so many science-related articles, it’s big on hype and over-promises with both its headline and article text.

First, this isn’t new. In 1994, Miguel Alcubierre published a paper12 detailing how we might construct a warp drive within the framework of general relativity. White (the NASA scientist mentioned in the Gizmodo article) is building on Alcubierre’s work, as others have (Van den Broeck, Krasnikov, et. al.).

The trick with a warp drive, or any space-time distortion within the framework of general relativity, is that it requires negative energy. What the hell is that? Just as matter has energy equivalence (E=mc2), “negative matter” has negative energy equivalence (-E=-mc2). We have circumstantially observed negative energy effects3, but only at tiny, tiny quantum scales.

When Alcubierre first formulated his warp drive (which, to be more precise, was a specific set of parameters fed into the field equations of General Relativity to attain the desired spacetime “metric” that would create a warp field), he realized that the (negative) energy cost of the drive would be greater than the mass of the entire universe4. Many scientists, inspired by his work, have come along since then and proposed improvements that have brought this requirement down5. This is what White is talking about with his “500 kg” figure.

The mass-energy equivalence of 500 kg of matter works out to 4.49×1019 Joules, or the equivalent of 10,740 megatons (10.7 gigatons) of TNT. In 2008, the world’s energy consumption was 4.74×1020 Joules, so it represents about 10% of the global energy production. Not an unattainable number, but still enormous–especially when it’s meant to be concentrated in one spot (a spaceship).

Assuming we had the ability to harness and channel that much energy, and assuming we could “flip” it so that it was negative energy rather than positive6, there are still some unresolved questions. The “great” thing about a warp field is that you’re moving spacetime, not an object through spacetime, so you don’t have to “obey” the speed of light. Light within your pocket of spacetime moves as fast as light always has: way faster than you. Light outside your pocket of spacetime moves as fast as it always has, too: way faster than you (outside of that pocket). The pocket itself is what moves faster than light.

But…that still means it’s possible for an observer to “see” you arrive before you leave, thereby introducing all sorts of time travel/causality issues. Causality is fundamental to, basically, everything we know about anything. Thing one happens, causing thing two to happens. Exceeding the speed of light — the speed at which information travels — breaks this. Thing two happens, then thing one happens and causes thing two. What? It doesn’t make sense; it’s not how the universe works. There is mounting evidence that, in fact, the universe must work with causality intact78, based on some really niche quantum mechanics stuff. This, alone, isn’t necessarily reason to lose hope, though. There are a number of scenarios and/or limitations wherein it’s possible that the nature of the warp field might distort space in such a way as to prevent “light cones” (descriptions of space and time relative to an observer) from inverting. TBD.

Finally, when one travels through space, one collides with all the little particles of dust out there. Space is unfathomably empty, but there are still a lot of them. Think about riding a motorcycle and bugs splattering on your helmet. Now, imagine that your motorcycle is traveling ten times as fast; those bugs just turned into bullets, and you’re dead if you hit one. Now, imagine you’re traveling faster than light and, rather than the bugs splatting against your windshield, they’re getting “caught” in the warp field’s leading edge as you travel through space. This particulate matter converts into energetic photons and other, more-exotic particles, at once, building up a doomsday radiation wave in front of your ship. When you get wherever you’re going, and shut off your warp field, this radiation wave is set loose. Everything in front of you, at the very least, is wiped out by what amounts to a supernova. It’s entirely possible that it isn’t directional, and instead just detonates — taking you with it.

So, yes, hurray! for serious reserach into FTL, and for not being satisfied with the speed of light being the absolute maximum speed at which one can traverse the universe. But just because NASA’s working on it, don’t kid yourself: this is a puzzle with a lot of really huge hurdles to overcome, some of which may be literally insurmountable.

And if they do build it, it might look like this.

  1. Alcubierre’s original paper on arXiv []
  2. The more digestible wikipedia article on the “Alcubierre drive” []
  3. The Casimir effect []
  4. The paper detailing the issue with needing ridiculous amounts of negative energy []
  5. Chris Van Den Broeck, Serguei Krasnikov, et. al. []
  6. We have no idea where to even begin with this one; we don’t even know enough to say if it’s possible or not! []
  7. Novikov’s self-consistency principle []
  8. Hawking’s chronology protection conjecture []