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Star Wars Prequels Space Science Technology

Death Star Science: The Physics Of Destroying An Earth-Sized Planet 173

StartsWithABang writes: The ability to destroy an Alderaan-like (or, ahem, Earth-like) planet has long been the dream of slashdotters everywhere. But generating the power necessary to unbind a planet — some 2.24 x 10^32 Joules — is simply impossible on board an object only the size of a small moon. But if, instead, you could house a 1-2 trillion ton asteroid (about 5-7 km across) made of antimatter and deliver it to the planet's core, Einstein's E=mc^2 ensures that the planet will be destroyed in seconds.
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Death Star Science: The Physics Of Destroying An Earth-Sized Planet

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    • Re:Obligatory (Score:5, Interesting)

      by jonsmirl ( 114798 ) on Sunday August 16, 2015 @10:27AM (#50326437) Homepage

      It isn't a normal laser, it is a gravity laser. The gravity laser compresses all of the matter in the way to the point where fusion occurs between all elements. This lets you poke a whole through the planet since the beam can get past the matter it has already compressed. While the beam is still on it will be pulling more and more of the planet into it. When you get enough captured in the beam, turn it off and left the compressed matter explodes via nuclear fusion.

      • Re: (Score:1, Funny)

        by Anonymous Coward

        "poke a whole" what? A whole *what* you illiterate clod?

        • by skam240 ( 789197 )

          A typo on an internet forum! Thank god you were here to make sure all of us were aware of this author's most grievous of sins. Clearly the author wasn't taking seriously the grave responsibility that comes with posting in an internet forum! Oh when will the Slashdot editors take resposible action and delete this post as we all know the most insignificant of errors that can easily be read around completely invalidates a point.

          Or in other words, go post in another forum and let the adults talk here.

      • by aurizon ( 122550 )

        If this is a hand held weapon, I hope you wear gloves...

  • by Anonymous Coward

    I could!

  • Darth Vader toooootaly wanted to do that, but when he popped down to the antimatter asteroid shop, they were closed.
    • Re:It was plan B (Score:4, Interesting)

      by ShanghaiBill ( 739463 ) on Sunday August 16, 2015 @10:11AM (#50326385)

      I don't think it would work as well as TFA suggests. Even if you could instantly insert a 5-7 tera-ton anti-matter asteroid into earth's core, it would not just instantly detonate. Only the surface, that was in contact with matter, would explode, sending a compression wave both inward and outward, pushing the matter and anti-matter apart. Plasma would occupy the space in between, but it would be too tenuous to provide enough energy to instantly blow the planet apart in just a few seconds. Sure, all life would be wiped out, and the planet would be blown apart, but I am not sure it would happen in just a "few seconds" like in the movie.

      • And electrical panels on FTL starships don't explode in sparks every time somebody rams into the hull. And cars don't blow up in huge fireballs every time they roll over in slow motion. And Micheal Bay's special effects budget is bigger than NASA's entire operation.

        Geez guy, have some empathy. It's the movies.

      • The movie obviously used time lapse photography so as to not be boring by making the single scene days long. Cinema magic and all that.
      • by LWATCDR ( 28044 )

        Greg Bear wrote a story using anti matter to destroy the Earth. It was two projectiles one made of neutronum and one made of anti-neutronium. and yes they blew up in the core along with some large fusion bombs planted along the plate boundaries.

    • Darth Vader toooootaly wanted to do that, but when he popped down to the antimatter asteroid shop, they were closed.

      "I'm sure that in 1985, anti-matter is available in every corner drugstore, but in 1955, it's a little hard to come by."

      • Those were the good ole days. But now they don't keep in on the opens shelves, you have to ask the pharmacist and if they don't like your looks you can't get it at all. :(
  • by Anonymous Coward

    So is space flight [rfcafe.com] according to the NY Times - in 1920.

    • by Anonymous Coward

      Yes, it's as impossible as flying to the Moon by flapping your arms. Some things just *are* impossible.

      Your type of reversed logic is insane because it can be used to justify anything, because there's no logical connection between the two things you're trying to "compare".

      And as for your "Space flight" example, except for a handful of people who went to the Moon nearly HALF A CENTURY ago, no one else has gone. And the Moon is "spaceflight" like jumping in the air is a 747.

  • by PvtVoid ( 1252388 ) on Sunday August 16, 2015 @09:46AM (#50326301)

    Please stop, Ethan. You make me want to amputate my brain.

    • by Anonymous Coward on Sunday August 16, 2015 @09:49AM (#50326323)

      Please stop, Ethan. You make me want to amputate my brain.

      Then you too can be a Slashdot editor!

      • by cats-paw ( 34890 )

        I think he's a pretty good science writer, or at least I enjoy reading his writing.

        Writing about obliterating the earth might be kind of frivolous but i'm not sure it makes him a bad science writer.

        Maybe you could give us your learned opinion as to what makes his writing so bad.

        Or was it just this article in particular ?

      • I just love how this is modded insightful instead of funny. It actually shows there is a very real problem with how people think the way slashdot is managed.

      • by antdude ( 79039 )

        I don't even have a brain. Can I take it? :)

    • Why use antimatter? I would prefer to use antematter, you know, the stuff that was here before matter existed.

    • by NReitzel ( 77941 )

      Maybe, but I -always- get uncomfortable about a scientist (or any other person) telling me that something is impossible.

      It's clear that the way to destroy a planet is to build a beam that will suppress the gluon binding force.

    • Please stop, Ethan. You make me want to amputate my brain.

      Amputations are boring; you should excise it with a "superlaser".

  • A sufficient number of nuclear warheads would be just as effective. You might have a few people surviving in hardened underground installations, but this is something we could accomplish with today's technology.

    There are probably several score of chemical or biological weapons that could also wipe out a planet or better yet wipe out just a targeted species on it while leaving much or most of the planet and its ecology intact.

    Unless we've already got so many habitable planets that we can afford to comp
    • by iggymanz ( 596061 ) on Sunday August 16, 2015 @10:38AM (#50326467)

      Ethan 'Bubblegum' Tate: We need some kind of Doomsday device to create an implosion like that.

      Professor Hubert Farnsworth: Doomsday device? Aha! Now the ball's in Farnsworth's court.

      [pulls on a lever; a platform appears with several Doomsday devices]

      Professor Hubert Farnsworth: I suppose I can part with one and still be feared.

    • by skam240 ( 789197 )

      Practicality doesnt enter into this. The Death Star was a terror weapon and with its ability to blow up planets, about as good as they come. They even spell this out for the viewer in Episode IV: A New Hope when one of the senior imperials goes on at length about fear of the space station keeping systems in line.

  • A death star, 150 km in diameter, can house a 5-7 km ball of antimatter and the matter necessary to bind with it. Therefore a death star could have the means in its volume to have sufficient energy to unbind a planet. QED

    • I think the general idea was that you need to get the antimatter to interact directly with the matter at the centre of a planet. You could posit that the death star was sending an immense stream of contained antimatter bound within some sort of energy beam which also worked to clear away regular matter in the upper crust.

      • by ShanghaiBill ( 739463 ) on Sunday August 16, 2015 @11:12AM (#50326549)

        You don't have to transport the antimatter through the crust and mantle. You can just send it directly into the core via hyperspace.

        • you don't need antimatter at all. The Death Star's volume is sufficient to house energy store that could impart enough to a laser or any other kind of particle beam to vaporize a whole planet. the premise is false.

        • Duh. If you've got hyperspace, why bother with antimatter? Deliver a big enough chunk of regular matter to the core and the instantaneous displacement of matter should do the trick.
      • No need, I've proven a Death Star can house sufficient energy store to power a laser that could disassemble a planet. The summary is just wrong.

      • by ceoyoyo ( 59147 )

        Why? If you used the antimatter and matter in a reactor to generate energy for a super laser, the laser beam would transport the energy to the planet. The energy transfer from the laser to the planet is much less problematic than from a ball of antimatter. If you tossed an antimatter asteroid at Earth it might not even hit the surface before it bounced off.

  • by Anonymous Coward

    Why would this incredibly huge number of 2.24 x 10^32 Joules be impossible to generate from a civilization capable of traveling at the speed of light in most small ships? Wikipedia says to accelerate to one tenth the speed of light requires 4.5 ×10^17 Joules. That is for a 1 ton mass. 2.24x10^32 / 4.5x10^17 = ~498 Trillion of those generators. That should fit in a "small moon" sized ship.

  • "Star Wars is impossible because we can't travel faster than light."

    Then ... "giant worms don't exist in asteroids"

  • Humans. We are already destroying the Earth.
    • by umghhh ( 965931 )
      Probably true and it even is as disgusting and slow motion as other weapons of biological mass destruction. OC in the movies you can even make virus that works in seconds (world war z for instance) so maybe the speed is not an issue but disgusting it still is.
  • Presumably, you wouldn't pump all the energy to destroy a planet in from the outside. Instead, you'd probably fire some kind of catalyst into the planet that causes fusion or fission throughout the planet. Keep in mind that most of a planet is already under very high temperatures and pressures. Potentially, even a strong muon beam or similarly heavy charged particles might start to induce fusion. There may also be many other mechanisms for inducing fusion or fission in solid matter that we simply don't know

    • Iron is the element with the lowest potential nuclear energy - it's the end point of fusion as a result Therefore there is no prospect of using the iron for such a process; the best you could hope for is some of the other elements in the planet. However getting them to react at the nuclear level would be very ambitious - and the iron would keep on getting in the way.
      • Therefore there is no prospect of using the iron for such a process

        You're stating the obvious.

        However getting them to react at the nuclear level would be very ambitious - and the iron would keep on getting in the way.

        The iron is mostly in the core. The mantle consists largely of magnesium, silicon, and oxygen, all elements that can undergo fusion (and do in nature). In addition, there are enough heavy elements that some form of catalyzed fission may also take place. A "Death Star" might also only work on so

  • by backslashdot ( 95548 ) on Sunday August 16, 2015 @11:23AM (#50326585)

    A 5-7km size asteroid? How would you house it in a space ship efficiently? You would need some sort of spherical spaceship. It might look like a moon from a distance, but what would aliens think as they got close to it?

    • by AmiMoJo ( 196126 )

      More practically you would need to simply propel it somehow, with shielding in front to deflect normal matter from its path. Propulsion would have to be non-contact (or made entirely of anti-matter itself, kinda impractical).

  • I need to know by friday...

  • by Anonymous Coward

    I know it simplifies the calculations, but there's absolutely no reason to need to separate every atom from every other atom in the planet. All you have to do (hah) is break it into about a few million roughly equal-sized pieces, which takes several orders of magnitude less energy, and would be just as spectacular and useful.

  • Already been done (Score:4, Informative)

    by NormalVisual ( 565491 ) on Sunday August 16, 2015 @11:39AM (#50326655)
    Greg Bear's The Forge of God [wikipedia.org] destroyed the Earth in this manner many years ago. An attacking civilization flung two large pieces of neutronium and antineutronium at opposite sides of the Earth, where they descended to the core and orbited each other for several weeks, until they spiraled in together and made bad things happen.
    • The beauty of fiction is that you can dream up all sorts of solutions to the problem. To borrow an idea from another space series franchise, If the Death Star fired a beam which lowered the gravitational constant in a volume inside the planet to near zero, the planet's rotational inertia would make it fly apart on its own. No energy (or matter) input needed.
    • by delt0r ( 999393 )
      Yea well when you can run around the galaxy with neutron stars in your pocket, you hardly need the antimatter version.
  • Why bother ... (Score:4, Insightful)

    by PPH ( 736903 ) on Sunday August 16, 2015 @11:51AM (#50326727)

    ... with the exact details? Just subcontract the Vogons to do the job.

  • I used to have a roommate who played Master of Orion 2 on his PC with an Intel Pentium 133MHz processor. His style of game play was to keep the A.I. at bay, gather significant resources, and build 32 Death Stars to systematically eliminate every planet. Every time 32 Death Stars fired upon a planet, the computer is brought to its virtual knees.
    • Every time 32 Death Stars fired upon a planet, the computer is brought to its virtual knees.

      I don't think we want to know what he did once he got the computer on its virtual knees.

    • I used to have a roommate who played Master of Orion 2 on his PC with an Intel Pentium 133MHz processor. His style of game play was to keep the A.I. at bay, gather significant resources, and build 32 Death Stars to systematically eliminate every planet. Every time 32 Death Stars fired upon a planet, the computer is brought to its virtual knees.

      I'm pretty sure thats a myth. You can only do that once per fight with one 'Doom Star' and it ends the fight.

      • I'm pretty sure thats a myth. You can only do that once per fight with one 'Doom Star' and it ends the fight.

        My roommate was disabled and spent years playing MOO2 (his favorite game). One Doom Star was enough to kill a planet. But he was good enough with his resources to build Doom Stars on a regular basis to use 32 Doom Stars per planetary kill for maximum overkill.

        • I'm pretty sure thats a myth. You can only do that once per fight with one 'Doom Star' and it ends the fight.

          My roommate was disabled and spent years playing MOO2 (his favorite game). One Doom Star was enough to kill a planet. But he was good enough with his resources to build Doom Stars on a regular basis to use 32 Doom Stars per planetary kill for maximum overkill.

          I'm pretty sure the game mechanic was that if you have one stellar converter in the fleet you get an option when your fleet engages that you use the stellar converter to destroy the planet and theres no battle. Once the fleet has engaged theres no option to then use the stellar converter on each ship; you'd have to retreat and wait till next turn to attack and use the stellar converter.

          • After reading the MOO2 wikis, perhaps it was 32 Doom Stars against the enemy fleet that brought the computer to its virtual knees. Once the enemy fleets were annihilated, my roommate annihilated the planets one by one. Since I haven't played the game in years, my recollection might be faulty.

            For the record, I only got a Doom Star once or twice when I played MOO2 in my misbegotten youth.

  • It's really easy to mind-fuck about that kind of stuff and avoid dealing with the human power mechanisms destroying ecosystems on the so far lucky ball we creatures live. Dream on...

  • Personally, I'd suspect that it would be far simpler, and likely more thorough, and even perhaps more efficient energywise to simply steer (or create) a small black hole to hit the earth. Even a small one would likely accumulate mass faster than it would evaporate, and would eventually, almost certainly, destroy the earth.

    A big asteroid of antimatter is ridiculously dangerous, ridiculously hard to move, and has the problem of fratricide: that is, blowing chunks of earth far enough away from the antimatter

  • by Dereck1701 ( 1922824 ) on Sunday August 16, 2015 @01:20PM (#50327119)

    The assumption in the article appears to be that the planet was blown apart with such force that it never reformed, who says that is the case? Just blowing the planet up to the point where it temporary ejected most of its mass and then eventually reformed into a lifeless rock should require significantly less energy.

    • by AmiMoJo ( 196126 )

      Looking at the on-screen explosion it doesn't seem like there is nearly enough mass ejected to account for a sphere of that size anyway. Either much of the matter was annihilated, or the Death Star was mostly hollow on the inside anyway. At the end of Jedi we see that there is at least one huge open chasm inside.

  • So, instead of the Death Star being a moon-sized platform for a laser, it becomes a kind of delivery truck for antimatter mini-moons with a self-unloader (the laser.)

    Cool

    But these antimatter mini-moons take a tremendous amount of energy to produce. Given that the calculated power to blast apart an earth-like world is the output of a Sun-like star for several weeks - and even assuming that the efficiency of the production of antimatter from energy is likely to better than CERN's billion to one ratio of

    • Don't worry, the whole premise is false. Assuming usual 3 percent conversion efficiency, the volume of even fusion fuel sufficient to disassemble a planet is sixty six (66) of those 5-7 mile diameter asteroids. That would fit into the volume of the Death Star's 150 km diameter. If that energy could be imparted entirely to a laser beam, it would be sufficient to vaporize an earth sized planet. No reason to put something in the core.

  • Red matter??? Amateurs.

  • by Meneth ( 872868 ) on Sunday August 16, 2015 @02:19PM (#50327351)

    The site "Things of Interest" (qntm.org) has a pair of better articles:

  • Antimatter is not a common beast, the odds to find an asteroid of antimatter seems scarce.

    On the other hand, a big asteroid made of plain matter can keep the planet intact while removing any life on it. Who needs more?

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