# Can a Death Star weapon actually be built?

#### lucas_

Star Wars revolved around the Death Star that could wipe out an entire planet.

Another movie is coming up soon so we can start to reflect on it.

Can a Death Star weapon actually be built? What could power it?

In nature, gamma ray burst can also wipe out a planet.

"The scientists calculated that gamma-ray radiation from a relatively nearby star explosion, hitting the Earth for only ten seconds, could deplete up to half of the atmosphere's protective ozone layer. Recovery could take at least five years. With the ozone layer damaged, ultraviolet radiation from the Sun could kill much of the life on land and near the surface of oceans and lakes, and disrupt the food chain."

What kind of civilization (I read it's marked by Levels II or III, etc.) can manipulate a black hole so the gamma ray burst or jets can be aimed at a planet and destroy the ozone? Could they do it?

Or could a Death Star like that in Star Wars be built that is designed to wipe out the ozone of a planet?

[Moderator's note: Edited. Political comment removed.]

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#### andrewkirk

Homework Helper
Gold Member
The action of the death star in Star Wars is completely impractical because not only does it wipe out life on the planet, but it quite unnecessarily causes the planet to explode so that its matter is flung off into far space. The energy to do that - which is essentially the negative of the potential energy of the Earth's mass, taking zero to be the potential energy infinitely far from the Earth - is unimaginably huge.

To kill all life on a planet would require a lot of energy, but nothing like that. Disturbing the ozone layer like you mention would be one way.

The lowest energy way I could think of to do it would be to use one or more asteroids that pass close to Earth. A sophisticated civilisation could slightly divert the course of those asteroids so that they hit the Earth - ie the opposite of what space agencies on Earth are thinking about to protect Earth from collisions. If they are prepared to wait for a close enough one, it needn't take much energy.

I should add that I am not in favour of wiping out all life on Earth, or on any other planet.

Staff Emeritus
Given that the physics of Star Wars is not the physics of the universe we inhabit, I don't see how this question can be answered.

#### lucas_

What's the biggest existing particle beam weapon now? How is it powered? Is the strength cumulative or linear?

#### jbriggs444

Homework Helper
What's the biggest existing particle beam weapon now? How is it powered? Is the strength cumulative or linear?
Let us instead consider the energy required to eject of one kilogram of planetary crust and compare it to the chemical energy content of one kilogram of TNT.

Escape velocity is 11 km/sec (at the Earth's surface -- more deeper down). $E=\frac{1}{2}mv^2$. So that's 60 megajoules of energy we need to supply. Google says you get about 4.2 megajoules from one kg of TNT. So to blow up the Earth we need a stick of dynamite with at least 14 Earth masses. [Or an Illudium Q-36 Explosive Space Modulator]

Edit: The recursive problem of getting a 14 earth mass stick of dynamite to explode is left as an exercise for the interested Sith.

Another edit: The 14 Earth mass estimate is on the high side. After the first kilogram has been ejected, escape velocity from the surface of the remaining mass is slightly reduced. The second kilogram is easier. The total binding energy is less than the sum of the original escape energies for all the component tidbits.

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#### Rive

Can a Death Star weapon actually be built?
I would prefer starting with an X-wing instead...

#### willem2

Another edit: The 14 Earth mass estimate is on the high side. After the first kilogram has been ejected, escape velocity from the surface of the remaining mass is slightly reduced. The second kilogram is easier. The total binding energy is less than the sum of the original escape energies for all the component tidbits.
The death star does not only evaporate the planet, but also makes the material completely disappear in just a few seconds. If you only give the material a speed of escape velocity, the earth would blow up quite slowly. a speed of about 10000 km/s seems to be involved. This will add another 6 zero's to the energy required.

#### pedro the swift

Far more practical to use a kinetic energy weapon like a diverted asteroid at as close as possible to light speed.

#### russ_watters

Mentor
The death star does not only evaporate the planet, but also makes the material completely disappear in just a few seconds.
What?!? No it doesn't! Did you even watch the movie?!?

#### Klystron

Gold Member
Far more practical to use a kinetic energy weapon like a diverted asteroid at as close as possible to light speed.
Terrific Sci-Fi novel; Niven and Pournelle at their best. The Fithp aliens live nearby as stellar distances go and are only slightly more technologically advanced than the humans. Along with the "flaming crowbars" kinetic weapons, the novel is filled with dramatic physics. From memory:
• a scene where a low-tech human warrior uses their opposable thumb to accurately throw a spear stabilized by spin, fooling the Fithp who use bifurcated elephant-like trunks as digits.
• Humans launch a massive concrete Orion from the surface of the Earth, sacrificing part of Washington state in order to save the Earth.
• Human scientists attack and destroy Fithp ships with gamma-ray lasers (grasers) powered by the nuclear explosions that propel the Orion spacecraft.
I read Footfall once back in 1985 but can still visualize the tech.

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#### willem2

What?!? No it doesn't! Did you even watch the movie?!?
Well, watched it again, and there's more debris around than I remember, but in a few seconds, there's no material inside the radius of the planet, confirming my speed estimate.

#### russ_watters

Mentor
Well, watched it again, and there's more debris around than I remember, but in a few seconds, there's no material inside the radius of the planet, confirming my speed estimate.
Watched what, the explosion sequence...? Later, when the Falcon arrives where Alderaan was, it finds an asteroid field that was Alderaan.

#### DaveC426913

Gold Member
Terrific Sci-Fi novel; Niven and Pournelle at their best.
Had two all-time awesome moments in science-fiction writing:

Humans light up the atom-bomb powered rocket 'Michael'.
WHAM!
WHAM!
WHAM!
God was knocking, and he wanted in bad.

fithp Captain: "What - what the hell is that??"
Human prisoner envoy (grinning): "That's us humans."
fithp Captain (eyes wide): "You're riding on atom bombs. It's suicide."
Human prisoner envoy (grinning): "And we're coming for you."
fithp Captain (in abject terror): "Make it stop. Make it stop now."
*paraphrased

#### Tghu Verd

Can a Death Star weapon actually be built?
Sure, why not, didn't we see one in the movie?

With tongue a little less in cheek, the Star Wars universe is innumerably ahead of us in terms of pretty much everything except tyranny and wisecracking sidekicks, so presumably their materials science is sufficient to build a moon-sized ship that can be moved without the stress of motion breaking it apart. They have AG so that seems plausible, but brushing up on the design, it does not appear to have much in the way of "habitation services" sufficient to keep a large population alive within it. So presumably, there are lots of bots and a small crew who are resupplied, rather than growing their own food. (Though honestly, who really knows. I'm guessing George Lucas was not elaborating every little thing with expectation to be double, triple, and quadruple guessed some decades later when he was originally writing his script!)

What could power it?
This is easier to answer. The Star Wars universe has FTL via hyperspace (rather than something like an Alcubierre drive) which implies additional dimensions. When you draw energy from a higher dimension space into our 3D universe, it translates into considerably more power here. (Small confession, I'm recalling this concept from my own sci-fi novel, so I know it works that way )

That allows the seemingly impossible outcome of a relatively small device - check out the schematics for the Death Star - to focus sufficient energy to destroy a planet. It doesn't even have to try that hard, those higher dimensional particles are so power-packed! Need to obliterate a troublesome Rebel planet stronghold? No problem, point the business end of the hyperspace trumpet at the place, fire up the warp drive generators, and ka-boom, the next thing that happens is a massive disruption in the Force. Oh, and a planet blown to rubble, of course.

Or could a Death Star like that in Star Wars be built that is designed to wipe out the ozone of a planet?
That's so un-Star Wars that it does not really deserve a comment. Sith Lord Darth Vader is a busy guy, he doesn't have the time to hang around for an environmental collapse, and besides, those pesky Rebel's are known to live in caves and such. No, this is not an option. Besides, who is going to be terrified of a 'Death Star' that takes a decade to murder the population? Perhaps that would work in the Monty Python Star Wars universe - "It's only a flesh wound" - but Lucas and Co. are way more ruthless than that!

#### jim mcnamara

Mentor
@jbriggs444 said:
[Or an Illudium Q-36 Explosive Space Modulator]
So where is @PeterDonis when you him?

On a practical side: the cost of building, maintaining and powering anything like a death would require 100% of the Gross Domestic product of many worlds. For long periods of time. Even with really awful people as bad guys why would you want to turn a huge part of your Empire's habitable planets into a slag heap?

Then: No more Empire. No more people or beings to oppress.

[sarcasm]
[/sarcasm]

#### lucas_

Remember the movie Ender's Game?
It may be difficult to base the Death Star planet destroyer on kinetic energy beam dynamics.

In Ender's Game. The beam can disrupt and shred molecules and causing chain reaction to entire planet.

So if the beam can be designed not for kinetic impact properties but to cancel the electromagnetic forces in matter. This can disintegrate the entire planet.

Theoretically, what would happen if all electromagnetic forces of atoms were cancelled in a given location such as a planet? Please describe what would happen.

#### jbriggs444

Homework Helper
Theoretically, what would happen if all electromagnetic forces of atoms were cancelled in a given location such as a planet? Please describe what would happen.
Theory does not say much about what happens if the theory does not hold.

#### Klystron

Gold Member
Remember the movie Ender's Game?
It may be difficult to base the Death Star planet destroyer on kinetic energy beam dynamics.

In Ender's Game. The beam can disrupt and shred molecules and causing chain reaction to entire planet.

So if the beam can be designed not for kinetic impact properties but to cancel the electromagnetic forces in matter. This can disintegrate the entire planet.

Theoretically, what would happen if all electromagnetic forces of atoms were cancelled in a given location such as a planet? Please describe what would happen.
I suggest reading the novel "Ender's Game". Orson Card based the novel on a short story featuring young Bean, not so much Ender IIRC. A memorable line from the short story came from a therapist asking the young veteran after the war something like "What will you do with your life now?". War-weary Bean had no idea what she was talking about. I presume Card meant to illustrate the plight of child-warriors and how war changes veterans.

Card names the ultimate weapon a "molecular disruptor" not from some profound theory but so that it would have initials M.D. like a doctor. Mazer Rackam and other teachers refer to the weapon as the "little doctor" and emphasize to Ender it was never intended to be used against a planet. After his desperate use of the little doctor against the Bug's home world, Ender and his sister travel through many sequels trying to atone for the genocide against another sentient species.

I could never watch the movie after a few frames. To paraphrase Heinlein I doubt if the director ever read the novel. I have read the series through "Speaker for the Dead" and, if Card is not a war veteran, he captures and relays issues facing veterans of modern electronic warfare quite well for what was originally youth SF.

#### Tghu Verd

Theoretically, what would happen if all electromagnetic forces of atoms were cancelled in a given location such as a planet? Please describe what would happen.
Hmmm, the electromagnetic force provides electricity and magnetism, it holds atoms together, it largely defines the internal properties of objects, and it is responsible for chemical bonds. If it was suddenly turned off, I'd say you'd have just created dark matter!

#### TeethWhitener

Gold Member
Besides, who is going to be terrified of a 'Death Star' that takes a decade to murder the population?
Gotta be honest, that actually sounds way more terrifying than instant obliteration.

#### Tghu Verd

Gotta be honest, that actually sounds way more terrifying than instant obliteration.
Change ozone layer to CO2-induced heat stress and we're pretty much living the scenario, @TeethWhitener

And I'm lurching off topic, but I wonder whether a killer asteroid hurtling at us would galvanize global action faster? We're generally an 'immediate threat response' species, which Darth Vader knows only too well (to slide me into the thread before The Moderator Strikes Back ).

#### lucas_

Hmmm, the electromagnetic force provides electricity and magnetism, it holds atoms together, it largely defines the internal properties of objects, and it is responsible for chemical bonds. If it was suddenly turned off, I'd say you'd have just created dark matter!
Not exactly right. You would still have the strong and weak forces.

How would matter behave if they are only ruled by these forces especially the strong force. Nucleons would still be intact. So you would have matter without any electrons only? How would they look like? How would a planet look like that is composed of nucleons only?

Also Death Star could deploy death rays not for kinetic damage but to change the planet into pure strangelets. I think I heard of this before about the danger of strangelets. Can anyone give idea how to intentionally cause strangelets to form and cause chain reaction into the entire mass or blob or strangelets?

#### Tghu Verd

Not exactly right. You would still have the strong and weak forces.
Yep, you're right, not quite dark matter.

Also Death Star could deploy death rays not for kinetic damage but to change the planet into pure strangelets. I think I heard of this before about the danger of strangelets. Can anyone give idea how to intentionally cause strangelets to form and cause chain reaction into the entire mass or blob or strangelets?
Given that strangelets are a hypothetical particle, you know you're going to get a hypothetical answer right?

But if by "the danger of strangelets" you mean the pre-LHC carry on by Johnson and Baram who noted Sir Martin Rees' claim that the LHC could feasibly convert the entire Earth into a strangelet blob, then I think we're well past that. Cosmic rays with way more energy than LHC hammer us all the time, so if strangelets exist and pose a risk of 'contagion', then it's more likely to have already happened (or on the Moon, which is why Evan Finch, at Southern Connecticut State University in New Haven, has searched for strangelets by running moon dust through a mass spectrometer. He hasn't found any!).

In terms of forming strangelets, check out Bob Holdom, Jing Ren, and Chen Zhang's recent models of strange quarks, which suggests that they are not viable members of the particle zoo.

#### lucas_

Its a sleepy weekend. What could be a good list of movies revolving around vacuum engineering and weapons deployed that target the vacuum hence planet destroying capability done not by kinetic or thermal methods but directly affecting the vacuum itself?

Who knows, the Death Star may employ such principle too.

#### jbriggs444

Homework Helper
Vacuum engineering. Gotta be Space Balls: "She's gone from suck to blow".

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