The 12 best planet killers in sci-fi

Whether it's an incredibly powerful bomb or a gigantic super-laser, nothing adds spice to a science-fiction story like the ultimate of ultimate threats: the planet killer. What else would we expect from our favorite heroes other than saving the entire world? Cliché or not, we all have our favorites, and here's our top twelve world-destroying devices along with some science behind the fiction.


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1. Death Star

Seen In: Star Wars (Episodes IV & VI)

What It Is: A gigantic spherical battle station the size of a small moon, boasting a planet busting "super-laser" prime weapon.

Readers of Star Wars non-canonical Star Wars fiction might point out that the "Sun Crusher" is a more powerful weapon, but there is no doubt that the menacing Death Star holds a distinction of being the most popular (or at least the most well known) planet killer in science fiction history.

How It Might Work: A laser, by itself, would have to possess a pretty wide beam to decimate anything as large a planet with a single brief shot like in the movie. The power source required to create such a beam would definitely need more than one thermal exhaust port only two meters wide.

Consider that the U.S. military has built an airborne laser to shoot down missiles. That laser requires the bulk of a 747 aircraft to house it. Given that a moon weighs roughly 165,000,000 times as much as a 747, an "operational battle station" is pretty "far, far away."


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2. Doomsday Machine

Seen In: Star Trek (TOS): The Doomsday Machine

What It Is: A cone-shaped, automated robot super-weapon made of solid "neutronium" that breaks apart planets with a beam of "pure antiproton." The machine then ingests the chunks of planet to refuel.

How It Might Work: The idea that a race intelligent enough to construct such an automated weapon with no safeguards that would keep it from running amuck throughout the universe seems unlikely. But, the antiproton beam described by Commodore Decker actually makes sense. When an antiproton collides with a proton (i.e. any type of matter) it gives off a tremendous burst of energy. This would be consistent with a machine that could convert planetary rubble of all sorts into fuel.


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3. Hand of Omega

Seen In: Doctor Who (Sylvester McCoy Era)

What It Is: The Hand of Omega was originally designed to harness a star's energy for time travel. The Doctor modifies it, so when it is stolen it essentially becomes a torpedo that can make a sun go supernova.

How It Might Work: To say triggering a supernova is difficult is like saying a nuclear bomb makes a loud noise when it goes off. The scale is difficult to appreciate. A nova is actually triggered by either a sudden increase or a sudden drop in a star's nuclear fusion. Unless we gain the power of inter-dimensional travel and can bridge a gap between two stars without actually moving them in the three dimensions, there's nothing else with quite enough power.


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4. Replicators

Seen In: Stargate SG-1

What They Are: An ever-evolving race of self-replicating robots

How They Might Work: The components of this technology are frighteningly within our grasp. Nanotechnology is a rapidly emerging field. While scientists haven't made fully functional "nanobots," they have managed to construct working machines built up from the molecular level. In 2005 U.S. researchers devised simple robots that could self-replicate with modular spare parts.

According to Stargate, the first Replicators were more or less pets for an Android. So if we start building robot pets that can rebuild themselves with spare parts at the molecular level… makes you look twice at your Roomba, doesn't it?


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5. Genesis Torpedo

Seen In: Star Trek II: The Wrath of Khan

What It Is: The latest thing in instant terraforming, best when used on a lifeless space body, like a moon or other dead form. It leaves a living, breathing, fertile planet, destroying any existing life in favor of its new matrix. Unfortunately, the use of proto-matter (a substance that every ethical scientist in the 23rd century has declared as "dangerously unstable"), made the original Genesis planet destroy itself in a small number of days.

How It Might Work: At this time an "all-in-one terraformed planet-in-a-box solution" hasn't yet been proposed. However, the use of missile-like projectiles to deliver life-giving properties to a proposed planet (or lifeless region) in the forms of chemical gasses for the atmosphere, chemical liquids, fertilizers, seeds, etc. has been considered by scientists. As for planetary destruction, probably not, but you still wouldn't want to get hit with a missile full of fertilizer and seeds.


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6. Monoliths

Seen In: 2001 & 2010 books and movies, plus 2061 and 3001 books

What They Are: Black, impenetrable objects varying in size from 3 meters to 2 kilometers with a consistent proportion of 1:4:9. The Monoliths are difficult to define. They are supercomputers (from the book 3001), guardians of our solar system and emissaries for a galaxy-roaming intelligence that can't be everywhere at once. In an effort to bring peace to an Earth that was about to destroy itself in a nuclear war, the monolith created a distraction (and a warning) by turning Jupiter into a small star, dubbed Lucifer.

How They Might Work: It would be improbable that anything could ignite the gasses in the solar system's biggest planet, thereby converting it to a star. Consider in the 1990s, the Shoemaker-Levy 9 string of asteroids struck the Jovian planet with the equivalent of 6,000,000 megatons of TNT (600 times all the nuclear weapons on Earth). It obviously failed to ignite it. But if the monoliths added a considerable amount of CO2 to Jupiter, thereby increasing its mass by a small order of magnitude, it just might be possible.


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7. Pirate Planet

Seen In: Doctor Who: The Pirate Planet

What It Is: A giant hollow spherical spacecraft that materializes around planets and mines them dry of all of their valuable raw materials.

How It Might Work: It's at the limit of human science now to instantaneously move a few particles from one place to another. It's safe to say, unless there is a serious breakthrough, that we are at least 50-100 years from something as incredible as a "Star Trek-style" instant matter transmission, let alone the technology to instantaneously move anything as big as a planet from one part of the galaxy to another. Still, if you could build a craft at such a scale, creating machinery that could tear apart the planet trapped in the interior would be the easy part.


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8. Species 8472 Bioships

Seen In: Star Trek Voyager: Scorpion

What They Are: Biological spaceships combining their energy into a planet-destroying beam

How They Might Work: This bears a striking resemblance to the super-laser on the Death Star. However, Species 8472's technology appears to be more biological or organic in nature. Plants have the ability to adapt solar radiation into energy at a rate of about 2 x 1023 joules of energy per year via photosynthesis. If this technology were developed and weaponized, it could become a method of channeling tremendous power from nature — maybe even enough for an incredible weapon.


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9. Xindi Superweapon

Seen In: Star Trek Enterprise: Zero Hour

What It Is: Massive Particle Beam Weapon

How It Might Work: The concept of a particle beam is actually not science fiction. A particle beam is just that, particles (atoms or electrons) accelerated to near the speed of light. Put simply, one could strip the electrons off of hydrogen atoms in a particle accelerator. Then, using alternating positive and negative electrical charges (similar to a maglev train), propel the particles in a beam. The energy requirements for a beam could approach a sustained 1 billion volts or more. Since the particles would disrupt the atoms in their target, a sustained beam would render even the toughest shielding nearly useless.


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10. Drej Mothership

Seen In: Titan AE

What It Is: Centrifuge Beam

How It Might Work: Not much is known about how the Drej mothership's beam weapon works, but it seems to be different from your average laser. From how it appears, it probably increases a planet's rate of rotation until the resulting centrifugal force rips the planet apart. Evidence of the Earth's current rotational speed can already be seen in its slightly Oblate spherical shape. Scientists say that the Indian Ocean Earthquake in 2004 caused the planet's rotation to increase by three microseconds. A nearby pass by a large enough gravity body like an asteroid could produce a change in the planet's rotation, but a beam doesn't seem plausible.


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11. Red Matter

Seen In: Star Trek (2009)

What It Is: Substance capable of creating a quantum singularity and thus, a black hole

How It Might Work: All red goop aside, the science of creating a Black hole is not so "far-fetched." It was originally thought the team at CERN operating the Large Hadron Collider (LHC) would be able to create micro black holes. These would be very short-lived and not exert the star-crushing, planet-munching gravity we were looking for. In an announcement last August, the folks at CERN said they would be able to make black holes by 2012. I'm sure conspiracy theorists are having a lot of fun with that one.


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12. USNC Nova Bomb

Seen In: Halo, Starship Troopers (book)

What It Is: Starship Troopers doesn't go into describing how this weapon works — it simply states it could "crack a planet in half." Not bad since Robert Heinlein wrote it at the dawn of the nuclear age.

Halo describes it as a knot of nine nuclear fusion warheads incased in "lithium triteride." The idea here that sets it apart from a regular fusion warhead is that the armor (made of a fictional material) is supposed to compress the radioactive material to the "density of a neutron star." This is what really makes it a planet-buster. According to Halo it would increase the power 100 times (that's 900 nuclear warheads to you and me and around 24,000 times the first nukes used in the 1940s.

How It Might Work: As everyone knows, nuclear fusion warheads, also known as thermonuclear warheads, are far more efficient and have a much higher yield than their earlier fission counterparts. Ramp up the scale to 1,000 times the yield of Tsar Bomba, the most powerful fusion weapon ever detonated on Earth, and there's your planet killer.