On Interstellar Travel
Part 3 of 3: Does the Warp Stare Back at You?
“When you stare into the Warp, the Warp stares back into you.”
– Warhammer 40k
As part of the 45th anniversary of the Moon landing, I’ve written a series of articles on interstellar travel. In the last two installments I covered slower-than-light interstellar travel and Star Trek’s warp drive. Slow travel is plagued with the problem of travel duration. After all, spending 150 years on a ship is not very appealing, and what happens if you run out of supplies? Warp drive sounds plausible, and even has a real-world mathematical analogue, but it has a high probability of causing space-time paradoxes.
So maybe we’re thinking too small. Maybe we don’t need interstellar travel schemes that are “plausible with existing physics”, after all they really aren’t all that plausible. Now we know that the Earth, Sun, and Interwebs are governed by Einsteinian physics. So if we want to break Einstein’s rules, we need to travel to a different dimension altogether! For maximum traveling comfort, this dimension should be immediately adjacent to normal space-time, and we should be able to bring along enough space-time to keep our physical bodies intact.
As it turns out, tons and tons of science fiction universes make use of a high-speed dimension immediately adjacent to regular space. This parallel dimension is called Hyperspace in most fictional universes, Slipspace in the Halo universe, and Ultraspace in Iain Banks’s Cultureverse. For the sake of convenience I’ve grouped them all under the umbrella of “Hyperspace”.
Because hyperspace exists outside of normal space-time, it doesn’t have to follow any of the laws of physics. However, if you want to give hyperspace a pseudo-scientific veneer, you can always invoke string theory. Unproven variants of string theory suggest that there are many extra dimensions adjacent to our own, rolled up into incredibly small spaces that we can’t access. If you could somehow squeeze into these alternate dimensions, you could move just a tiny bit and find yourself halfway across the universe. Ta-da, realistic hyperspace!
There’s one big problem with string theory hyperspace: the extra dimensions are very, very small. Not just regular small, incomprehensibly small: on the order of a Planck length. This is so small that if a proton was enlarged to the size of the Earth’s orbit, a Planck length would be the size of a DNA double helix. Passing a camel through the eye of a needle is downright trivial compared to traveling through such a tiny dimension. Also, physicists aren’t sure that string theory is real, and the string theorists aren’t sure that the extra dimensions are real. So scientifically speaking, string-theory hyperspace seems much less plausible than warp bubbles or even time travel.
I guess the scientist with a comical lisp was right for once – it was never supposed to be “hyperspace”, it’s “hypothspace” – a hypothetical space.
So let’s forget reality, and get into some different fictional concepts of hyperspace.
At a very basic level, hyperspace concepts can be split into “safe” and “dangerous” versions. Let’s start with safe hyperspaces, as they are much more common. In safe-hyperspace universes, hyperspace is pretty darned boring. You could kill yourself by dropping out of hyperspace on top of a star, as alluded to by Han Solo, but you’re unlikely to die in hyperspace itself. Depending on how hyperspace works, it may not be possible to fight a battle in hyperspace.
Safe hyperspaces may be further divided based on method of hyperspace entry. In Star Wars and Halo, ships can enter and exit Hyperspace/Slipspace at arbitrary locations. Less advanced ships may suffer from restrictions on where they can jump, while high-tech ships can enter and exit Slipspace at will.
In terms of their narrative impact, these “go-anywhere” hyperspaces are really not much different from warp-bubble drive. You could replace every warp core in the Federation with Corellian Hyperdrives of equal speed and reliability, and no one would really notice. Of course, canonical Star Wars velocities are much higher than Trek velocities, but they’re probably the same now.
One big problem with the “go-anywhere” drive is that they tend to give space combat an offensive bias. With no spaceborne equivalent to terrain or chokepoints, the attacker will enjoy advantages in mobility, initiative and surprise. It’s no coincidence that Star Trek, Star Wars, and Halo all place some emphasis on the idea of “don’t let the enemy find our fleet / superweapon / homeworld.” Once they discover your point of vulnerability, it’s awfully hard to defend – even when you set a trap!
This leads to the next category: “restricted hyperspace”. Maybe unassisted interstellar travel is extremely slow, expensive, or dangerous, but most travel occurs with the help of jump points, wormholes, mass relays or other fixed devices. These “jump paths” make interstellar travel downright easy, but your movement becomes predictable. Babylon 5, Mass Effect, and Honor Harrington all use variants of this hyperjump concept.
The restricted-hyperspace concept is highly appealing to writers because from a plot perspective it behaves much like terrestrial geography. Well-charted jump lanes are like major roads, while low-quality jump lanes are like back-country roads. Governments, bandits, and invading baddies all want to seize control of the jump paths, as they are the most economically valuable part of the star system. On the other hand, unassisted hyperspace is like a spooky forest that you can hide in, diving into “uncharted jumps” to evade pursuit. Just watch your back; hyperspace may be dark and full of terrors.
Restricted hyperspace also allows military forces to set up strong defensive chokepoints, slagging invading forces as they funnel through a wormhole or mass relay.
In some universes, hyperjumps may be “hard-restricted”, making FTL utterly impossible outside of spacelanes. This “hyperspace on a rail” concept removes all possibilities of escaping into uncharted space. It is pretty unpopular in fiction, but very common in gaming. The Freespace, Master of Orion, and Sins of a Solar Empire series all use hard-restricted jump geometry, as does Every Space Board Game Ever. Games prefer hyperspace-on-a-rail for its simplicity, as true 3-dimensional movement is very difficult to pull off in videogames and frankly impossible in boardgames.
In a minority of hyperspace systems, it is impossible to stay in hyperspace for any measurable amount of time. Instead, ships rapidly jump in and out of hyperspace in “stutter warp”. This is a relatively rare form of warp drive, originally published in the tabletop RPG 2300 AD and popularized by the novel A Fire Upon the Deep. Because each stutter-jump is instantaneous, you don’t need to worry about how time flows while you’re traveling faster than light: it doesn’t. Otherwise it’s not too different from go-anywhere hyperdrive.
From a realism perspective, all of these hyperspace concepts are purely speculative. You could say that hyperspace is “further out there” than Trek warp because there’s not as much supporting math, but you could also argue that the math proves that Trek warp is impossible. Until the physicists discover radically new branches of physics, FTL travel will remain impossible in our existing scientific understanding.
Back in the Age of Sail, exploration was so dangerous that many explorers never returned. Human imagination concluded that there must be an endless number of monsters in the sea, from seductive sirens to terrifying dragons. Of course, the deep seas of Earth never contained any sirens or dragons, but the danger was real and the body count high.
Just as the ocean was terribly hostile to flimsy ancient ships, hyperspace may be a very hostile place for future starships. Perhaps hyperspace is simply so bizarre that people go crazy by staring into it, as in the Ringworld series. Or maybe foldspace is filled with subtle hazards that can only be percieved by highly specialized individuals, such as the Spice-addicted Guild Navigators in the Dune series.
Or maybe the sirens and dragons aren’t just figurative… The Trope Namer, Warhammer 40k, describes starships traveling through The Warp, a dimension full of immeasurably horrific Daemons and Chaos Gods. This is similar to the dimensional gates used by H.P. Lovecraft’s Elder Gods, and is probably inspired by Lovecraft to some vague extent.
In a universe where FTL travel is extremely dangerous, interstellar trade and travel would be difficult and expensive. Anyone willing to travel a long distance through Chaos would have to be desperate, crazy, or seeking a large payoff. Any substance that makes travel safer would be incredibly valuable, sought after and hoarded by every military force in the galaxy.
Hazardous-FTL universes tend to be more violent and militaristic than gentler universes. Part of this is narrative bias; someone who would write a completely peaceful story is unlikely to make hyperspace a violent place. However, it’s also a logical consequence. If hyperspace is highly dangerous, only highly dangerous people would feel comfortable with it. The hazards of space travel would discourage merchants and schoolchildren to a much larger extent than pirates, mercenaries, terrorists or madmen.
Now it’s interesting to speculate what might happen if a hazardous-FTL society became much less hazardous. Intercontinental travel was near-suicidally dangerous in the 16th century, but routine in the 21st. If the same thing happened in a WH40k-esque setting, would the galaxy become more peaceful? Probably (although not in WH40k, that’s just ridiculous).
How much of the violence in pre-industrial human civilization was caused by the fact that everyday life was so deadly that there was less of a taboo on killing? I’ll leave that question to the anthropologists, historians and philosophers, but it seems to me that it’d be responsible for some of human violence. I think it would be very interesting to set a sci-fi novel in the midst of a cultural transition between an ultraviolent “Warhammer” setting and a peaceful “Star Trek” galaxy.
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So that’s it for my semi-systematic ramblings on interstellar travel. The fact is that with our current understanding of physics and outer space, mankind is not going to take any small steps under an alien star. Someone will need to discover the next domain of physics, whether he’s a brilliant academic mind or a half-crazy drunk. And on the day that his work is publicized, all of us sci-fi enthusiasts will cry. Half of our tears will be shed in joy at the advancement of mankind and space travel, and the other half will be shed in mourning over all the pseudoscience that’s suddenly as dated as Jules Verne’s moon cannon.
Post your comments if you got any!