A long time ago a great disturbance was felt in the force as millions of voices cried out
in terror, and were suddenly silenced. But c'mon, could the Death Star really blow up
a planet?! It’s Star Wars day, you guys (screams)
Hey jedis and siths, Trace Windu here for DNews -- get it? Like… Mace? Okay… A key
plot point in the original Star Wars story was the destruction of the planet Alderaan
by the Death Star as a show of force to the Rebel scum. Then, after the destruction, an
asteroid field formed around Alderaan's star, but c'mon... would all this really happen?!
Yes, the movie is science fiction, but when have we nerds ever let that stop us from sciencing
the sh*t out of something?
Okay, first we need to know how much energy it takes to blow up a planet, then we can
work out if the Death Star can blow up something so much bigger than itself. Alderaan is an
M-Class planet, right? It's earth-like and similarly sized. Three nerdy researchers at
the University of Leicester calculated how much power the Empire would have to impart
into the planet to get it to overcome its own gravity and fly in all directions. It's
a really big number: 2 octillion joules. The World Energy Consumption is only 56 billion
joules! So these numbers are pretty difficult to fathom. Let's put it in perspectives we
can comprehend, sort of… The power of our whole sun is 380 septillion joules, astronomers
call this ONE solar luminosity. Ahh, small numbers.
So, the energy required to blow up a planet, according to these researchers would be 5.2
solar luminosities, or the amount of energy of our Sun releases in a week. Which is pretty
insane. Phil Plait, Bad Astronomer and internet-winner extraordinaire, says depending on the planet's
size though, it could be more like 582,000 solar luminosities! That would take 57 quadrillion
megaton nuclear bombs to blow up! I love me some Plait, but for the sake of simplicity
let's go with the students… we want it the answer to be in reach, after all.
To generate all that energy, we need to understand how the Death Star is powered. According to
authors in the Extended Universe, I know, its hypermatter reactor is as powerful as
"several main-sequence stars." As we're basing these numbers on our own Sun's power of one
solar luminosity, the Death Star may throw power around equivalent to say seven of our
sun -- or seven solar luminosities! THATS WAY MORE THAN the 5.2 needed to blow up a
planet! Note: our sun is a relatively small main-sequence star, so this is a pretty conservative
estimate.
But, it could be even easier than all that. Shooting a big laser at a planet would just
heat it up -- and you'd have to get through all that mass to reach the core and vaporize
it… very unlikely. Popular Mechanics got a bunch of SciFi authors together and brainstormed
the problem. My favorite hypothesis is that the superlaser fired by the Death Star is
positronic; a positron is a positively charged antimatter twin of an electron! If they fired
a pure antimatter beam at Alderaan it would cause massive matter-antimatter explosions!
When matter and antimatter meet, they annihilate each other in a huge release of energy. Because
these antimatter-matter reactions are so powerful, according to author Ethan Siegel, you'd only
need the amount of antimatter equivalent to 0.00000002 percent of the mass of the planet
being destroyed! Even Phil Plait agrees that might do it!
But then what? In 1977, George Lucas described Alderaan as a planet in a system, it not exactly
canon, but other planets definitely exist. When the Death Star's superlaser destroys
it what happens to those six other planets? Not too much. Asteroids accelerated by the
release of heat and pressure from inside the planet would shoot toward the outer reaches
of their solar system, but overall the Alderaan system would be about the same… the mass
of the planet would distribute around a new asteroid belt; and the system would move on…
Think of it like Mars' moon Phobos, it's set to be torn asunder in the next 50 million
years, but it won't disrupt the orbit, the mass is going to be pretty much the same.
A quick wobble, then back to business as usual.
Look, this is science fiction, it's a fanciful story. But the best part about science is
it can make these stories feel more real. Arthur C. Clarke's Third Law of Scientific
Prediction is, "Any sufficiently advanced technology is indistinguishable from magic."
If the Empire can wield many times the power of our whole sun in a single spacecraft -- it
would be like magic to us. But of course, no matter how powerful the Death Star was,
it is insignificant, next to the power of the Force. I'd like to thank Dr. Natalie Hinkel
for helping me with all this stellar math, btw! She's awesome.