This article is part of the Fantasy Science & Coffee column on Film Inquiry
One of the most captivating science fiction staples is faster than light (FTL) travel. In our last segment of Fantasy Science & Coffee, we chatted about FTL travel in popular science fiction, and what would happen if you were to move at light speed. Let’s now take a look at how some of our favorite sci-fi FTL mechanisms relate to science.
Hyperspace and Extra Dimensions
A number of science fiction stories involve travel via hyperspace, which gives one a nice workaround to travel unbelievably vast distances without violating the universal speed limit. As mentioned in Part I, the term ‘hyperspace’ isn’t actually fictional, it refers to space with more than our regular three dimensions.
Hyperspace travel is notably used in the universes of Star Wars and Stargate. Stargate scientist Dr. Rodney McKay describes it fairly succinctly:
Okay, so at its base level, a hyperdrive allows you to travel great distances by entering and exiting subspace.
The really cool part of this is that many scientists believe, based on the mathematics of string theory, that extra dimensions do exist. In string theory, there are certain equations that just do not make sense unless you introduce more dimensions than the three spatial dimensions and one time dimension we perceive.
The question is, what would these extra dimensions look like? Physicist Brian Greene presents a nice visual when he talks in the World Science Festival’s Hidden Dimensions: Exploring Hyperspace.
If you zoom in to the underlying dimensional grid that we perceive, the extra dimensions would appear to be curled up and entwined. These tiny dimensions seem counter-intuitive because we can’t perceive them, so I’ll turn to a bird perched on a twig for some illustrative help.
At a distance, the branch appears to be a single, two-dimensional line. Yet, as we zoom in, we see that the bird’s talon is actually wrapped around the branch. There is a curvature that we couldn’t perceive at a distance.
At this stage, the work is only theoretical, but has merit, and there are already strides being made to detect extra dimensions with the help of the gravitational force. I’ve linked to string theory resources below, for the more curious reader.
Let’s move on to the concept of ‘warp’. Trekkies out there are no strangers to this word. It’s a ship’s warp drive that allows one to travel faster than light.
Interestingly enough, in 1994, a physicist named Miguel Alcubierre, intrigued by the terminology in Star Trek, proposed a potential warp drive model. Why haven’t we written off such a romantic model as nonsense? The proposal is actually mathematically sound, being a solution to Einstein field equations. These field equations tell us how mass and energy can be distributed in the universe. So when I say ‘solution’ to these equations I mean, “this is a valid relationship between mass/energy and the geometry of space-time.”
The Alcubierre Drive theoretically warps space-time in such a way that a flat space-time is enclosed in an extremely curved space-time bubble. The bubble is propelled forward by contracting the space in front of it, and expanding the space behind it. A starship inside the bubble would be able to “ride along” within it.
This warp drive may sound fairly simple in theory, and you might wonder, “How soon can I plan a vacation to Alpha Centauri?”, but it will be a fairly long while before this is possible; there are many pitfalls to work out in the mathematics, and a better understanding of how the universe ticks is required.
This video by PBS Space Time, explains some of the obstacles along with the working of the drive:
We likely won’t see real manifestations of this research for many generations to come, if it is indeed true at all, but it is fun to fantasize about.
What do you think about these unproven theories? Do you think FTL travel is possible?
More to Explore
The Guardian: Tying loose ends? Gravitational waves could solve string theory, study claims (2017)
Physics Today: What every physicist should know about string theory (2015)
NASA: Warp Field Mechanics 101 by H. White (2013)
The Astrophysical Journal: Apparent Faster-Than-Light Pulse Propagation in Interstellar Space: A new probe of the Interstellar Medium (2009)
Phys. Rev.: Traveling Faster than the Speed of Light in Non-Commutative Geometry (2001)
A nice StackEx answer: Layman’s explanation and understanding of Einstein’s field equations
Icarus Interstellar – a non profit foundation dedicated to accomplishing interstellar flight by the year 2100