Could the Death Star destroy a planet?

 Wikipedia En F F9 Death Star1 Could the Death Star really destroy a planet? Back in 2008, I posted that astrophysicist and mathematician Jeanne Cavelos, author of The Science of Star Wars, speculated that indeed, the Death Star could be that deadly. Last year, another group of scientists published a paper addressing the same question. And these researchers from the University of Leicester's Department of Physics and Astronomy came to the same conclusion. According to the paper abstract, "A simplified planet is used giving an energy required to destroy as 2 x 1027 J. Since the Death Star's power source has a much greater energy output it is feasible to destroy a planet with such a space station." Of course, such a space station doesn't exist. But, well, yeah. "That's No Moon" (PDF, via Astrobiology Magazine)


  1. So basically it’s “Lucas and some guys say so, that’s why.”  

    Ah, if only all science were so easy.

  2. In your post you are missing the units of the energy, which is 2*10^27 Joules (it is present in the linked article.) In other news, I feel much stupider for having read this. Basically the article says that, as  kaellinn18 alluded to, it can blow up a planet because they said it could in the movie.

      1. Also, FTR, your post (and the abstract in the PDF) say that the power required is 2×10^27 J, while the body of the paper in the PDF says it’s really 2×10^32 J.  I have no idea where the number in that abstract comes from; pretty much every calculation I’ve found on the internet on this (and the web link to Astrobiology Magazine) agrees with the 10^32 number.

        1. pretty much every calculation I’ve found on the internet on this […] agrees with the 10^32 number.

          If you’re referring to the white paper by Maslow and Mahadevan, that calculation was debunked in 2001 by the same conference in Geneva that led to the general theory of fictional measurements. That theory’s predictions for who would win in a fight between Neo and Agent Smith matched the third Matrix movie so precisely that practically everyone in the field has adopted it as the standard model.


      1. A seminary is where they study justice, hope, peace, ethics, morality, law, love and the human condition.   None of those things exist, right?

        Oh wait, you do think they exist?  Okay, let’s take justice.  You think justice exists?

        Prove it.

  4. Well, you’d need a beam of really hard gammas, no?   Otherwise it would tend to make a hotspot right on the surface and *shove* a planet, like project Orion or laser-heated remote propulsion. But come to think of it, that would have given a novel “exploding planet” explosion, rather than the common radially symmetric variety (and no, adding a ‘saturn’s rings’ blast wave isn’t my idea of “novel.” Now the opening seq. of MIB II, they did right by poking fun!)

    They could have opted for “physics correctness” and gone around melting planet surfaces as they slowly rotate under them, like Niven’s story “Inconstant Moon.”

    1.  I was thinking that also.  You’d just create an extremely hot spot on the surface that would continue to suck up the energy.  This has always been a problem for laser cutters, you need to get the molten stuff out of the way.

      Seeing as the planetoid that is believed to have hit the earth and created the moon didn’t destroy the earth I doubt even this imaginary beam could.

  5. This reminds me of the people who are mad at Marvel Comics for classifying X-Men toys as “non-humans” (for tax reasons, it makes them not “dolls”) – since this action recapitulates the comic & movie plots of prejudice against mutants.

    Who don’t exist and can’t be offended.

    EDIT: Wait, Astrobiology Magazine? Whaaa?

    1. Mutants don’t exist? Wikipedia think they do. There generally appears to be a lot of information about altered DNA. Although if I were a mutant, I think I’d be so afraid of prejudice against me, that I’d keep it quiet…
      (Unless you mean “super human ability” mutants don’t exist, which I agree seems very unlikely.)

      1.  Literally every human being on earth is technically a mutant, so I don’t think there would be much prejudice as far as that goes.

  6. Since the death star had a very large ‘hypermatter’ reactor, which possessed an output equal to that of several main-sequence stars…

    Um… do they even need to say anything else?

    Except they didn’t even do any math after that. Let’s do some. They say that the sun has an output of 3 x 10^26 J/s. “Several” suns probably have an output of 10 x 10^27, or 10^27 J/s then.

    The Earth apparently requires 2.25 ⨉ 10^32 J to destroy it. Therefore it would take (2.25 ⨉ 10^32) / (10^27) = 225 000 seconds = 62.5 hours

    62.5 hours!

    Did I do the math wrong, or did I just prove that these guys, far from proving that the Death Star is possible as shown in the movie, instead proved that the Death Star could only blow up the planet after several days of continuous shooting at it?

    By the way: Woah, is this a strange coincidence when doing the math in Google:

    1. Hmmm, I note that the quote above uses the number 2×10^27 J to destroy a planet. This comes from the article’s abstract, but is not mentioned anywhere in the article itself, where an entire different number is used. What the Hell is with this article? Was it written by prefrosh?

      1. That’s what I thought.  The ‘paper’ only mentions 3 numbers (earth energy, jupiter energy, sun power) and one equation. Somehow they manage to use a different and unexplained number in the ‘abstract’.

        When you add the unexplained ‘we used a simplified model’ and other bullshit handwaving, it’s so bad it’s “not even wrong”.

        You can have a lot of fun trying to apply real physics to movies (e.g. Arnie had to be strong in Commando since he must’ve been carrying  0.5 metric tonnes of lead). This study fails.

    2. Our sun is only one example of a main-sequence star.  In fact, if you look at the Wikipedia page on main-sequence stars ( you’ll see that the luminosity (energy output) of main sequence stars can be several orders of magnitude larger than that of our sun.   Several main sequence stars with luminosities 100,000x that of our sun would only take a few seconds to output 10^32 J.

  7. I did this math once- it’s just the gravitational binding energy- and then kept playing with some of those goofy fan-canon facts you seem to absorb by osmosis, and it actually makes for a nice revisionist backstory. So if I might be permitted a few lines of bored hypernerd- I promise I’m not taking this seriously…

    If you just assume the Death Star is running on some sort of synthesized fuel or energy storage- antimatter, maybe, with a healthy dose of handwavium- and assume too that said handy superstuff runs all the blue glowey engines and the antigrav hot rods and the FTL and the pwey-pwey guns, and take the million planets of the Empire, and the number of shots the Death Star was prepared to fire, and the construction time from Episode III to IV, it works out that each and every planet in the Empire is exporting a minimum of thousands (and with thermodynamic loses, more like tens to perhaps hundreds of thousand) times the total energy production of the Earth today, which are numbers that represent at minimum paving your entire planet with solar cells and in the mid-range can chew up all the thorium, uranium, and deuterium in your planet. And sure, the Republic was maybe building solar power satellites  and tiny, hot black holes with droids for a few millenia, but it’s still probably a tall order.

    On top of that, the Death Star is clearly an absurd weapon. The whole of Alderaan, down to the core, probably wasn’t one giant Rebel rabbit warren. Death-ray-ing cities with nuke-sized blasts for the better part of an afternoon probably would have sufficed. Even melting the top few miles of crust, or boiling the oceans, would have been suitably heinous, alarming, and effective, and spared all the energy in boiling off mantle rock where no one lived.

    Add the two together, and the truth comes out- the Empire is in the midst of a massive energy crisis fomented by confiscatory tariffs to power showy, militarily useless superweapons. Rebellion is brewing on the ten thousands planets that can’t get supplies from space, and whose terraforming droids are sitting idle as the planet grows toxic and cold. Our plucky space heroes, when they aren’t chewing on Zen koans and lassoing giant walking tanks, are really playing Robin Hood with Imperial fuel tankers, running wild in their little SpacePriuses while Imperial murder-cruisers fiddle their thumbs in orbit for want of a tank of gas. That big fleet that takes on the second Death Star is mostly made of defecting Imperials and their ships, who have just about had enough of watching a crazy old wizard who clearly doesn’t know a damn thing about physics, economics, or strategy drive the wheels off both the galaxy and the New Order he built to police it.

    Now go watch the movies again :-P

    1. Good point about not needing to blow the whole planet up.  I’d go one further and say all they needed to do was either toss something massive at it (like in Starship Troopers) or nudge it into an eccentric orbit so it ends up going from being boiling hot to having its atmosphere turn to snow.  Probably would’ve taken less energy.


        Good point about not needing to blow the whole planet up.

        Except that it was a PR event.  They weren’t killing them to kill them.  They were killing them for the 6PM news.

        1.  Thanks for pointing this out, I was going to say the same thing. You can’t have these nerd-wankery discussions if you’re going to misunderstand basic things about the plot!

  8. It’s as if millions of voices suddenly cried out in terror and were suddenly silenced… by the fact that the Deathstar is fictional and this is pointless. But it is fun.

  9. So let’s ignore the source of the power, can you build a laser that soaks up 2*10^27 J and converts it to usable coherent light?

    If you can do that, I remember there’s some funky stuff happening if you soak vacuum with too much energy. Would the energy-density in the beam be any trouble?

    I’m pretty sure the empires hypermater generator can’t output 2*10^27 J continously. So would they have some sort of capacitor bank? What’s the required surface area of a dielectric sheet to hold that charge?

    The power lines transporting the charge to the laser, basically how thick would the wires have to be (assuming they’d be supraconductors with near neglible resistance)?

    Assuming the wires could transport the charge, how well would you have to anchor the cables and what amount of force can you expect on the wires due to routing 2*10^27 J trough them in electricity in a short amount of time?

    Of all said aforementioned machinery, how large would the resulting electro-magnetic fields be? And would they be survivable for anything on the deathstar during operation?

    1. You have a great point, Florian.  What kind of machinery is required to generate an energy beam (as opposed to, say, a Magnetic Accelerator Cannon, as in the Halo games, or some other projectile weapon, even one capable of causing a truly massive nuclear chain reaction within the core of the targeted planet) that is sufficient to transform an Earth-analogue planet into an asteroid field as near to instantaneously as makes no difference?
      Fictional machinery, that’s what.  I am neither astrophysicist nor overeducated SF geek, but if I were driving a Death Star and wanted to wreck a rebellious planet’s day, I imagine I might as well just ram my small-moon-sized craft into it.  If I’m going to flip a few switches and fire up a Death Ray that is apparently either so incredibly well-focused or so pathetically wimpy that personnel can sit right next to it as long as they wince and stick their fingers in their ears, I have to wonder just how I’m generating, transforming, conditioning, and radiating that much energy.  Again, it’s not just enough energy to blind all the Alderaanians on the day side of the planet, nor enough to boil the oceans, nor enough to eventually burn a hole right through the planet.  It’s enough to make it explode like a Bantha turd on the windscreen of a landspeeder.

      “Millions of voices suddenly cried out in terror… and were suddenly silenced”?  Yeah, right.  Nobody even had a chance to wonder what the green dot in the sky might be before Ka-Boom!!

      And Darth Vader has the effrontery to proclaim, “The ability to destroy a planet is insignificant next to the power of the Force.”  Tarkin exterminates billions of lives and untold trillions of Galactic Credits’ worth of prime real estate at a stroke.  Vader chokes a dude from across the room.

      I tellya, the series would have been much improved had Tarkin and Fett lived longer, and Vader tripped over his own cape and impaled himself on old Obi-Wan’s lightsaber.

  10. Reminds me of the canonical arguments between Star Wars and Star Trek fans over whether Federation starships could defeat Imperial stardestroyers. Apparently some Star Wars book was published that indicated power outputs by simple Star Wars freighters in the “mid-size star” range.  This was used to beat the Star Trek people over the head to the great delight of the Star Wars supporters.

    It was all fun and games until a fan of the original series showed up and explained in horrifying detail what a sub-light Romulan Bird of Prey can do.  I believe the quote was from the episode “Balance of Terror:”  

    “Can you see it?   We’re a mile deep, on an asteroid.  Almost solid iron!  And even through our shields [one plasma torpedo] did all this!”  

    He is referring to the fact their base is in flames.   According to Spock, the second shot vaporized the entire base along with a physical shield of “cast rodinium, the hardest material known to our science” which shatters in his hand.

    Some quick calculations were done and some faces became pale.  Then he explained that Birds of Prey have cloaking devices and could approach to within a thousand kilometers of a Star Destroyer’s engines before firing and then vanishing again.  He pointed out the deadly efficiency of submarine combat in WWII to back up his point.

    He was about to launch into speculation about what would happen if that Romulan ship had transporters and could beam fusion warheads on to the stardestroyer bridge when the Star Wars people retreated to the freighter argument again.

  11. The “death” star is a silly weapon.  You could destroy civilization on a planet by dropping a large enough rock or asteroid on the planet. 

    1. That would likely be the easiest way.  And of course if you’re capable of accelerating stuff to relativistic velocities (a gentle but sustained push from your own system, say), you could throw your garbage at the target world and sterilize it; such a bombardment might be much harder to defend against than an asteroid attack.

      1.  Possibly necessitating an arms race, since your defense would either be moving your planet or (at theoretical minimum) destroying the incoming missile/matter using the same potential energy.

        1. Ah, but you see the “beauty” of the idea is that there would be virtually no forewarning.  (I’m making the assumption of no FTL here; back to the “real” world.) That would certainly make it hard to launch a defense with the same kinetic energy, since the incoming has had ages to accelerate up to a considerably fraction of lightspeed.  Besides which, if the intercept happened within typical orbital distance, the resulting blast of radiation might still be quite damaging to the world below.

      2. You don’t need relativistic velocities to do damage to a planet in a gravity well. 

        If you mean to attack another star, it wouldn’t be a serious attack.  It would take years and simply wouldn’t have enough accuracy to hit a moving planet from light years away.

  12.  Just lob a chunk of antimatter at your target. The energy doesn’t have to come from the Death Star power supply. It could be stored internally like torpedos in a submarine.

  13. Probably a strong neutron beam jacketed with a piercing force field and it would blast into the planets metal core, find the uranium and turn it to a critical mass but the bang would be so big as to take the death star out

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