- In science fiction, coming up with technology that makes scientific sense matters.
- Nuclear weapons are now a cliched way of bridging current weapons technology with that of the hypothetical future.
- Simply put, nuclear weapons do not work in outer space the way we assume they should. If you’re writing science fiction, find something else. Now.
Today I decided to take a page from Erik’s book and talk technology. Nuclear weapons are one standard armament for future humanity, usually classed as a transitional technology. If you need something bigger than a pistol, but can’t quite make a phaser, laser, or photon torpedo yet, nukes are the next best thing. Unfortuantely, science tells us that they just won’t work in space the same way they do down here. So, if we’re writing science fiction (i.e. fiction that falls within the realm of scientific plausibility) we need to look elsewhere.
There are plenty of examples of stories using nuclear weapons in science fiction. Some older Star Trek novels about the early days of the Federation have starships carrying nuclear weapons. They appear also in the made for TV movie Babylon 5: In the Beginning, where John Sheridan destroyed the Minbari flagship Blackstar with nuclear mines. Nuclear tipped torpedoes played a role in the early seasons of Stargate: Atlantis. The human cruiser Daedalus employed them ineffectively against the Wraith (they were shot down before impact), though they were later transported into the enemy cruisers via Asgard beaming technology. In all cases, they are seen as the best technology of an emergent species and are usually only marginally effective at best. They provide a connection between our world and the one in the future, and give the storyteller a chance to make the audience feel intimidated when they see the most powerful weapon known to man fall short.
What we know about the basics of nuclear weapons makes them all the more fearsome. When detonated, preferably a short distance above the ground where it can do the most damage, a nuclear device sends out massive successive waves of energy. According to the Federation of American Scientists, roughly fifty-percent of this energy is sheer concussive force (the blast wave passing through the atmosphere), thirty-five percent is some form of thermal radiation (heat), and the remaining fifteen percent is nuclear radiation (neutrons, gamma rays, and residual radiation). The incredible destruction of Hiroshima and Nagasaki using bombs with much lower yields than what is available today (or would theoretically be available to a space-faring humanity) illustrate the incredible destructive power of nuclear weapons.
The only problem is that nukes don’t work that way in space. At all.
It turns out that space is missing a vital component: atmosphere. In this case, we aren’t talking about a simple lack of oxygen, since a nuclear reaction in a vacuum is quite possible; we’re talking about a lack of a conductor. No atmosphere means that there is no medium through which two of the three waves of energy travel. The blast wave owes much of its destructive force to the sudden compression and then expansion of the air around the detonation. You can actually see this wave traveling through the air in some videos of nuclear explosions. The air also provides the fodder for the thermal wave and conducts much of it away from the center event in the form of the massive fireball. In short, without a substantial atmosphere surrounding a nuclear detonation, it could lose eighty-five percent of its destructive power. The lack of atmosphere does have one “positive” effect on a detonation: the radiation released affects a much broader area since there is no air to absorb it as it passes by.
What would happen if we were to detonate a nuclear weapon in space? If NASA is right–and I presume they are–the results wouldn’t be all that impressive. There would perhaps be a dull pulse of light and then…nothing in particular. There would be a release of radiation (not all that much in the grand cosmic scheme of of things) and that would be it.
Therefore, nuclear devices really aren’t that useful in terms of science fiction (if we take science seriously*). Deployed in a vacuum, they have no explosive power and no incendiary elements, leaving only an increased radiological yield. A purely radiological weapon probably wouldn’t be of much use because, due to the significant amounts of radiation produced by the cosmos anyway, any potential spacefaring craft would already be heavily shielded against it. A little more probably wouldn’t make much difference.
Do we need to dispatch with nukes altogether? No, but we should use them in our stories intelligently. Nukes are very effective inside an atmosphere, and therefore could be effectively deployed planet-side — that can include larger nukes for use in planetary bombardment (think Battlestar Galactica) and smaller, tactical ones for use on a battlefield.
If you’re looking for a good replacement, I would suggest railguns. Real advances in recent years have convinced me that if we as a race are about to step into space, railguns will be the weapons we take with us. They really are quite amazing. That’s something I’ll discuss next Thursday.
*Of course, an alternative method of dealing with it is to just call it science “fantasy” and then no one will care whether it makes scientific sense or not!