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Starts With A Bang

This Is How You Can Create Your Own Real-Life Death Star

There’s real, straightforward science behind the destruction of an Alderaan-sized planet.

In all of science fiction, perhaps the most iconic moment of destruction occurs in 1977’s Star Wars: A New Hope, when the evil Galactic Empire unleashes a superweapon that destroys an entire planet — Alderaan — that bears many similarities to Earth. The spacecraft that delivers this crushing blow, the Death Star, reappears in subsequent Star Wars films, and looks poised to make an appearance in the upcoming Rise of Skywalker as well.

Even though it’s ultimately destroyed, rebuilt, and destroyed again, the idea of packing such an enormous amount of destructive power into a single shot seems to defy a reasonable scientific explanation. However, experimental advances have made what was once an idea exclusive to science fiction a real-life possibility for future supervillains everywhere. Here’s the science of how we could actually destroy an Alderaan-like planet.

Destroying an entire planet is one of the most energy-intensive tasks a supervillain can dream up. In order to blow up a planet, the greatest force you have to overcome is the gravitational force, as every atom that makes up that world is held together through the mutual force of gravity binding every mass together.

Consider that Alderaan is similar in size and composition to Earth, using the mass and size of Earth as a proxy for Alderaan should allow us to calculate the amount of gravitational self-energy binding such a planet together. With a mass of ~6 × 10²⁴ kg and a mean radius of ~6,400 km, distributed in layers throughout the Earth, we’d have to impart a total of at least 2.2 × 10³² J (224 nonillion joules) of energy in order to completely blow an Alderaan-like planet apart. Any less, and the force of gravity will bring at least most of the planet back together in short order.

An enormous amount of gravitational binding energy keeps planets intact, but imparting at least that much energy into a planet’s core would cause it to explode and become gravitationally unbound, destroying it in a similar fashion to how the Death Star destroyed the planet Alderaan in Star Wars: A New Hope. (PUBLIC DOMAIN)

In addition to the enormous amount of total energy needed to blast a planet apart, the timescales are also of great importance. This single blast from the Death Star doesn’t just destroy the planet Alderaan, it destroys it in mere seconds. The idea for how this could occur is set forth in the movie by coining a new word: a superlaser, but that can’t do the job the way that science demands.

The typical way that laser power is increased is by storing a large amount of energy in a series of cells or capacitors, then concentrating all of that energy into a pulse that’s released over extremely short timescales. The techniques that have led to the greatest human achievements on this front were awarded the 2018 Nobel Prize in physics, and have resulted in petawatt (10¹⁵ W) lasers. However, these lasers would have to be quadrillions of times as powerful in order to make the Death Star a physical possibility.

So many more things become possible if your laser pulses become compact, more energetic, and exist on shorter timescales. The second half of the 2018 Nobel Prize in Physics was awarded for exactly that innovation. (©JOHAN JARNESTAD)

If we consider another possibility, like one inspired by the processes inside our Sun, suddenly the Death Star doesn’t seem so implausible. Deep inside the core of the Sun, a total of 3.8 × 10²⁶ joules of energy are released every second: a number that’s much closer to the power required to destroy an Alderaan-like world. If we could somehow harness the energy equivalent of what the Sun puts out over the course of a week and release it all in one shot, we could gravitationally unbind the atoms and molecules that hold a planet together.

That, too, might be an impractical task, but if we look at how the Sun gets its energy, we can easily find the key to unlocking such a literal doomsday weapon as the Death Star.

The anatomy of the Sun, including the inner core, which is the only place where fusion occurs. Even at the incredible temperatures of 15 million K, the maximum achieved in the Sun, the Sun produces less energy-per-unit-volume than a typical human body. The Sun’s volume, however, is large enough to contain over 1⁰²⁸ full-grown humans, which is why even a low rate of energy production can lead to such an astronomical total energy output. (NASA/JENNY MOTTAR)

The Sun derives its power through the process of nuclear fusion, transforming light elements into heavier ones and releasing energy in the process. The heavier elements that form are lower in mass than the sum total of the masses of the lighter elements that reacted to produce the heavier ones, and the mass difference then gets converted into energy via Einstein’s E = mc².

By fusing hydrogen into helium, which converts about 0.7% of every hydrogen atom’s mass into pure energy, we can compute that a total of 4.3 million metric tons of matter into energy each second. If you could build up a week’s worth of all the energy released in the Sun via matter-energy conversion and store it, then releasing it all in one burst, you could use that energy to destroy a planet as massive as our own.

The most straightforward and lowest-energy version of the proton-proton chain, which produces helium-4 from initial hydrogen fuel. This is the nuclear process that fuses hydrogen into helium in the Sun and all stars like it, and the net reaction converts a total of 0.7% of the mass of the initial (hydrogen) reactants into pure energy, while the remaining 99.3% of the mass is found in products such as helium-4. (WIKIMEDIA COMMONS USER SARANG)

However, you don’t want to release the energy on the Death Star itself, which is what you’d have to do if you wanted to create a laser pulse. If you were to do so, the release of energy would cause tremendous heating and expansion from the point-of-origin of the laser pulse, which would destroy the Death Star itself before it destroyed the planet it was targeting. You wouldn’t need a well-piloted X-Wing or Millennium Falcon to destroy the Death Star; simply activating this doomsday device would do the deed.

Instead, you need that energy to be released not only on the planet itself, but in the interior of the planet. If you simply deposited that energy on the planet’s surface, the subsequent explosion would deposit energy outward into space, with only a fraction affecting the planet. The goal is to not only impart this energy to a world like Alderaan, but to impart it in the central core.

These cutaway illustrations of Earth and Mars showcase some compelling similarities between our two worlds. They both have crusts, mantles, and metal-rich cores, but the much smaller size of Mars means that it both contains less heat overall, and loses it at a greater rate (by percentage) than Earth does. Causing an enormous release of energy on a planet’s surface is unlikely to destroy the planet itself, but if that energy is released in the core, complete annihilation is possible. (NASA/JPL-CALTECH)

Although it might seem like a laser pulse is the obvious delivery mechanism for such a shot — given that laser light is already a form of pure energy that interacts very efficiently with matter — hitting a planet’s surface with a superlaser would fail to blow it up. If the laser is powerful enough to hit the atoms it encounters and move them out of the way, penetrating the ground beneath it, then it will cut straight through the planet.

Instead of depositing the majority of its energy in the planet’s core, it would cut through the entire world, leading to a laser shot that flies through mostly empty space. The planet’s core, despite begin extremely dense and packed with matter, would simply have its atoms pushed out of the way of the laser’s photons. A laser, on its own, cannot destroy an Earth-like world.

Whenever you collide a particle with its antiparticle, it can annihilate away into pure energy. This means if you place enough matter and antimatter in the same confined region of space, they can annihilate to completion, converting 100% of their combined mass into pure energy, via Einstein’s E = mc². (ANDREW DENISZCZYC, 2017)

However, there’s another option that a technologically advanced enough species could implement: to turn some of the matter in the planet’s core into pure energy, again leveraging Einstein’s E = mc². If we could transform a total of 2.5 trillion tons of mass into pure energy, that would be sufficient to gravitationally unbind and destroy an entire planet, exactly as Grand Moff Tarkin would have desired.

There’s one perfectly, 100% efficient way to transform matter into energy, and that’s by colliding it with an equal amount of antimatter. Instead of a laser, if you could somehow place 1.25 trillion tons of antimatter into the Earth’s core, it would spontaneously annihilate with 1.25 trillion tons of matter, producing all the energy you need (via E = mc²) in the location that you need it, destroying the world in question after all.

A variety of asteroids and comet nuclei are shown here, to scale and with their sizes in their known dimensions illustrated. An asteroid comparable to 2867 Steins or 5535 Annefrank made out of antimatter could indeed destroy the Earth if it were deposited in our planet’s core. (NASA / JPL / TED STRYK EXCEPT: MATHILDE: NASA / JHUAPL / TED STRYK; STEINS: ESA / OSIRIS TEAM; EROS: NASA / JHUAPL; ITOKAWA: ISAS / JAXA / EMILY LAKDAWALLA; HALLEY: RUSSIAN ACADEMY OF SCIENCES / TED STRYK; TEMPEL 1: NASA / JPL / UMD; WILD 2: NASA / JPL. MONTAGE BY EMILY LAKDAWALLA)

You might worry that this is an extraordinary amount of mass, and indeed it is large when you take terrestrial scales into account. But if you look at the objects in our Solar System, that’s only the size and mass of a modest asteroid, such as 5535 Annefrank, illustrated along with some other well-known asteroids and comets above.

If there were some way to create and contain this amount of antimatter aboard a Death Star-like device, and then deliver this solid chunk of antimatter into the planet’s core, it would be the perfect way to destroy Earth, Alderaan, or whatever planet we chose. When you realize that an actual superlaser could carve a path to the core of a rocky planet where the antimatter object could then be delivered, all of a sudden the idea of a real-life Death Star doesn’t seem so fictionalized.

A portion of the antimatter factory at CERN, where charged antimatter particles are brought together and can form either positive ions, neutral atoms, or negative ions, depending on the number of positrons that bind with an antiproton. If we can successfully capture and store antimatter, it would represent a 100% efficient fuel source, but many tons of antimatter, as opposed to the tiny fractions of a gram we’ve created, would be required for an interstellar journey. (E. SIEGEL)

Over the past decade, experiments into antimatter — such as at RHIC, the LHC, or the antimatter factory at CERN — have achieved a number of fascinating milestones. They have:

  • created neutral antimatter atoms, in the form of anti-hydrogen,
  • confined and controlled these atoms, keeping them stable for nearly an hour at a time,
  • found ways to create heavier antimatter nuclei, such as anti-helium,
  • and have measured the atomic spectra of antimatter, finding it to be identical (as expected) to normal matter.

Current research includes working on further advances, such as measuring its gravitational properties, creating new types of antimatter ions, and even creating bound states of anti-atoms: the first anti-molecules. Over the coming years and decades, antimatter physics may even lead to antimatter lattices and/or crystals. If you can create and isolate this antimatter under vacuum conditions, you could store and transport it anywhere.

The ALPHA-g detector, built at Canada’s particle accelerator facility, TRIUMF, is the first of its kind designed to measure the effect of gravity on antimatter. When oriented vertically, it should be able to measure which direction antimatter falls, and at what magnitude. Experiments such as this were unfathomable a century ago, as antimatter’s existence was not even known. (STU SHEPHERD/TRIUMF)

The Death Star may have begun as a purely fictional creation to represent imperialism, military power, and hubris run amok, but the idea of completely destroying a planet with a space-borne superweapon is truly possible given our current understanding of physics. By creating and storing a large enough stockpile of antimatter, using a realistic laser to cut a path to a planet’s core, and then depositing that antimatter in the core, planetary destruction becomes physically inevitable.

Travel the Universe with astrophysicist Ethan Siegel. Subscribers will get the newsletter every Saturday. All aboard!

A sufficiently resource-rich mad scientist, once we unlock the practical creation and storage potential of neutral, stable antimatter, could turn the Death Star into physical reality. The power of science literally holds the secret to destroying an entire world. By leveraging mass-energy equivalence, matter-antimatter annihilation, and a little bit of near-future technology, an asteroid’s worth of antimatter could deliver you your own galactic empire!

Ethan Siegel is the author of Beyond the Galaxy and Treknology. You can pre-order his third book, currently in development: the Encyclopaedia Cosmologica.


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