A question on /r/askscience talks about how big a nuke would have to be to disperse Jupiter. A question here on StackExchange talks about whether or not the Death Star could "Take out Coruscant" due to the planetary shields around it (from the EU/Legends).

Just how strong was the Death Star's superlaser, in terms of of tonnes of watts?

I'm guessing there is no exact number, but if we know that the Death Star destroyed Alderaan (that should be fairly easy to calculate using the formula for gravitational binding energy of a spherical mass) and if we assume it could have destroyed Coruscant, how strong would its laser need to be?

EDIT: I suppose I wasn't clear in my question, I wasn't asking for Wookieepedia entries on how powerful the superlaser was, I was asking based on the fact that it could destroy a planet and overwhelm planetary shields, how strong would the laser have to be.

  • Wookieepedia's Legends article on the superlaser says 2.4x10^32 W, but cites no source.
    – Null
    Commented May 19, 2015 at 17:15
  • This answer cites the same figure and guesses that the source is The Essential Guide to Weapons and Technology. I can check that book when I get home, unless someone beats me to it.
    – Null
    Commented May 19, 2015 at 17:25
  • 3
    since there was no time travel involved it was clearly less than 1.21 jiggawatts.
    – KutuluMike
    Commented May 19, 2015 at 17:26
  • Could someone explain why I've been downvoted? Does the question not fit the rules?
    – JohnN
    Commented May 19, 2015 at 18:00
  • Chad's answer (here) specifically answers this question.
    – Valorum
    Commented May 19, 2015 at 18:14

1 Answer 1


None of what follows is Canon.

I'm not aware of a source in either Canon or Legends, but real actual physicists from the University of Leicester wrote a paper calculating the energy requirements of the Death Star, appropriately titled "That's no Moon". Using a simplified model of an Earth-like planet, they calculate the gravitational binding energy. From the abstract:

A simplified planet is used giving an energy required to destroy it as 2 x 1027 J[oules].

But the question asked for Watts, which is just Joules over time. The scene from A New Hope is on YouTube. By my count, the complete beam is sustained for three seconds. According to my hyper-accurate math, this puts the Death Star's power output at approximately 6.67 x 1026 Watts, at minimum.

Going back to actual physicists, the "That's No Moon" paper makes some claims about the Death Star's power output, citing the 2007 novel Death Star:

[T]he death star [sic] had a very large 'hypermatter' reactor, which possessed an output equal to that of several main-sequence stars.

Our sun is an example of a main sequence star, and it has an estimated energy output (luminosity) of 3.846 x 1026 Watts.

  • Several Sol-like stars would output 11.55 x 10^26 Watts, so requiring half that amount to destroy Alderaan is quite reasonable.
    – RonJohn
    Commented Dec 6, 2017 at 4:38

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