Sci-fi writing tricks: balancing drama with plausibility

I am a great fan of science fiction that’s plausible enough to be ‘scientific’, but which doesn’t take the ‘science’ so far as to be boring.

In the miniseries that launched the re-imagined Battlestar Galactica a decade or so ago, Galactica took a direct hit from a nuke and survived with near-undiminished fighting capacity. Is it plausible?

Test Baker - a 23kt Mk III nuclear bomb detonated underwater off Bikini Atoll on 25 July 1946. US DoD, public domain.
Test Baker – a 23kt Mk III nuclear bomb detonated underwater off Bikini Atoll on 25 July 1946. US DoD, public domain.

The answer’s yes…and no. Operation Crossroads – atomic tests on Bikini Atoll against a fleet of warships in 1946 – revealed that large armoured vessels were resistant to an air-burst. But radiation was a killer, even inside the hulls, and over a surprising distance. Underwater blasts were even worse for radiation. Test Baker, an underwater nuke, crushed the closer ships, and the whole test fleet was showered with thousands of tons of lethally ‘hot’ water, contaminating every vessel with radioactive detonation products and un-fissioned plutonium. The reason was that water is far denser than air – and far more destructive when pushed by the colossal forces of an atomic fireball.

Rapatronic picture of an atomic explosion. Spikes are extensions of the fireball into the guy ropes stabilising the testing tower. Mottling effect is caused by the bomb casing, already vapourised and reflecting off the shock front of the fireball.
Rapatronic (‘Rapid Action Electronic’) picture of an atomic explosion milliseconds after detonation. Spikes are extensions of the fireball into the guy ropes stabilising the testing tower. Mottling is the bomb casing, vapourised and reflecting off the shock front of the fireball.

So why was Galactica’s survival plausible? In space there is neither air nor water to be pushed ahead of the expanding blast wave; all you have is the blast itself, along with bits of stray casing.

The Galactica SFX portrayal of the hit was scientifically correct in that sense – lots of glare, but even the characteristic ‘mushroom’ cloud was absent: there was nothing to generate it.  Destructive effects in a ‘space nuke’ are from direct electromagnetic energy, spewed across a ridiculous span of wavelengths from hard X-rays down to radio, coupled with the kinetic and thermal impact of super-heated, super-fast plasma from the bomb material itself. What it means is that the area effect is limited and diminishes with distance, per the inverse square law.

That underscores the other reason for plausibility: the re-imagined battlestar was huge, some 1.4 km long and 0.5 km wide once the flight-pods were extended. So the nuke effects were there – but for story purposes the heavy construction and (partial) armour of the ship apparently protected it from serious damage. In one episode it was revealed that Galactica was also equipped with massive water tanks along the inside of the hull – an excellent damper for hard radiation.

To me that was sci-fi at its best: a solid nod in the right direction, even if it wouldn’t stand up to specific mathematical analysis, helping create the suspension of belief needed to accept the silliness of other premises. These included artificial gravity inside Galactica (Einstein says no), a propulsion system with a specific impulse obviously running way beyond what physics allows, and an FTL ‘hyperdrive’ with spinning mechanical parts.

The hard part about this technique – suspending disbelief by using genuine science as far as possible, thus rendering the ‘handwaved’ parts more credible – is getting the balance right. I think the writers of Galactica hit the target.

Needless to say, Galactica wasn’t the first time the effects of a nuke going off in vacuum had been portrayed in sci-fi. As far as I can tell the first  description was penned by Arthur C. Clarke in his 1955 novel Earthlight, part of the only really scientific description of a space battle I’ve ever read. As an aside, anybody who’s read the novel is welcome to discuss the supposed science gaffe in that battle sequence, down in the comments. I think it was deliberate. Clarke knew his science. In fact, there were at least two hand-waved aspects to Clarke’s depiction of the battle – underscoring his genius as a writer. Thoughts?

And does anybody have an opinion about Galactica?

Copyright © Matthew Wright 2017


5 thoughts on “Sci-fi writing tricks: balancing drama with plausibility

  1. I don’t think I ever watched Battle Star Galactica, but I’m right there with you on the science-for-credibility idea. If a story contains science that is at least /possible/, no matter how unlikely, I can suspend disbelief, but some of the stuff that passes for sci-fi is just wishful thinking with a lot of hand waving.

    Some aspects of the hand-waving – such as FTL – have become so familiar that I no longer go ‘what the?’ But others just have me shaking my head – space ships that can descend into the gravity well and land on planets thanks to artificial gravity? Windows in space craft? Really? Sheesh, and my area of relative knowledge is biology, not physics.

    But even implausible sci-fi /can/ be interesting if its main purpose is to place characters in impossible situations that bring out the best and worst in them, or their cultures. I guess each reader has to draw that line in the sand as to how much real science they want or need. I’m pleased that Andy Weir’s novel, The Martian, gained so much acceptance /because/ of the science.

  2. BSG is “space opera” which, if I understand the definition of the genre correctly, has more to do with battling fleets of space navies than anything else. A good example would be David Weber’s Honor Harrington series.

    The logistics of space navies is an interesting subject. What sort of industrial/economic base would be needed to build vessels the size and complexity of something like the Galactica? Of course that question is largely rhetorical, without knowing the necessary technological base.

    That said…big fan! I especially liked some of the old-fashioned touches that looked like they were straight out of World War 2.

    One other note: how realistic is it to build a small ship like the Viper and expect visual acquisition of targets and atmosphere-style dogfights? In a space environment where beyond-visual-range combat is probably the norm rather than the exception?

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