Wednesday, March 2, 2011

Death Star Physics Revisited


I've been thinking more about the "Death Star Physics" problem from last year in which I estimated it would take about 2.1×1032 J of energy to blow up a planet.  It strikes me that I should have taken this problem even further.  How many photons were in the laser beam that blew up Alderaan?

As you can see from the video, the laser is green.1 Green light has a frequency f = 5.6×1014 Hz.  Using Plank's constant h = 6.6×10-34 J·s, one can compute the energy of a single photons by using the well known formula

E = h·f

From this we can compute the total number of photons,

number of photons = (total energy) / (energy per photon) =  ( Etot ) / ( h · f ) 
 = ( 2.1×1032 J ) /[ ( 6.6×10-34 J·s ) · ( 5.6×1014 Hz) ] 
= 6×1050 photons

This is a huge number. It's a 6 with 50 zeros after it. I'd have to go back and check, but I think this is the biggest number I've posted on this blog.

[1] At least the visible part of the laser is green.  It's possible the are also UV or other high frequencies of light coming out of the laser.


  1. But, when the Death Star fires, you can see that a number of beams are combined without a physical mirror, suggesting that it is not a laser, but a particle beam. Most likely, it is an antimatter particle accelerator that is blowing up the planets.

  2. This explosion, as recorded, could not have been made as a result of green photons as the primary energy source.

    We see the Death Star add the energy to the system in less than a tenth of a second, after which we see a bright ring expand at roughly 'c', and less than a second later macroscopic stony debris passes the Death Star, moving so slowly (and not radiating visible black-body radiation) that we can identify it.

    I think the only explanation (and this is outside the envelope of known physics) is that the beam contained truth and beauty quarks. The green was merely Bremsstrahlung from some unknown type of containment field for the free quarks. These T&B quarks would have interacted with the Iron core to produce a tiny black hole. The bright ring was an artifact of the collapse of the planet's magnetic field. The asteroids would have been transported a cosmically short distance via short-lived Klein-bottle worm-holes to the distance observed.

    In the end, many less than 10^50 photons were required, but lots more other stuff added the required energy.