Welcome back to dumb questions, the show where we ask dumber and dumber questions until we break science. Today’s question is, how fast is light?
As you can probably guess, really damn fast. Light, which is composed of pure energy travels at 3×10^8 meters per second, or in pleb-speak 671 million mph. By comparison the fastest human alive, the aptly named Usain Bolt has clocked in a top speed of 27.8 mph. It would take you 280 days traveling at world record speed, to cover the same distance light travels in a second, unless you’re The Flash of course.
Traveling the speed of light is small feat though, it takes a lot of energy, but how much energy? Well, so it gets complicated, once you start nearing the speed of light Einstein shows up and takes a massive dump on all your calculations. I’m not really qualified to speak on matters of relativity, but from what I understand as you accelerate closer and closer to the speed of light it takes more energy to keep accelerating. Eventually you find that it would take an infinite amount of mass to accelerate an object of mass, say an ostrich, to the speed of light.
But let’s pretend you’re The Flash (you wish you were that awesome) and can travel at the speed of light, what would happen? Again, I’m not an expert on relativity, but from what I understand, you would be instantly vaporized. In the first few nanoseconds you would collide with the air in front of you, heating to the point where it would catch fire. In the next few nanoseconds your skin and bones would be simultaneously melted and shredded as the fireball in front of you grew to the size of a small city. Eventually you would probably blindly hit a wall or something and the rest of your mass would be converted into pure energy. The resulting explosion would be on the order of 1.4 gigatons, which is 60 thousand times more powerful than the bomb dropped on Nagasaki.
For those of you enterprising mad scientists out there hoping to weaponize this kind of energy, I wouldn’t bother, you’d likely end up blowing yourself up, before you ever blew up the moon. But if you were to build some sort of battle station with some sort of death ray…
How long would it take to destroy the Alderaan System? Well young Skywalker, the thing most people forget about space is everything is really far away. Say for example you were in orbit around a certain blue planet at the distance of its moon, it would still take 1.38 seconds for your death laser to reach the planet. If, for funnies you wanted to blow up Pluto, because no one will let you live down your demotion of its planet status…
It would take about four hours before for your death ray to blow up the dwarf planet. That’s enough time to watch Birdemic TWICE, and still have time to pack your undies before hightailing it out of there. Now if you wanted to destroy the next star system over, Alpha Centauri, it would take 4.4 years for your beam to reach them. During that time you could watch Birdemic 25,713 times! So it wouldn’t be a million voices crying out in terror and then being suddenly silenced, as it would be a million voices crying out in terror and gradually dying down after they got bored of watching Birdemic for 4 straight years.
But what if, the centaurs on Alpha Centauri saw you shoot a giant death ray at them, and while it was still traveling they built their own death ray to shoot your laser out of the sky with their laser. Would it work? No….well… probably not. Particles of light don’t interact with each other, except, at really high energies. The interactions aren’t very well understood, in fact it’s one of the things they’re testing at CERN, but in theory if you take two photons of high enough energy, they can collide and create matter. So instead of destroying a planet you might actually create one.
But let’s say your an advanced super-society living under threat of annihilation by space laser, what would be the best way to avoid getting blown up your galaxy’s equivalent of Grand Moff Tarkin? I suggest one of two solutions. You can either throw enough garbage at the incoming laser that it blows up the garbage instead of your planet, or you can try and use a black hold to deflect the laser beam enough that it misses. Or you can combine the two plans and just put a black hole the path of the laser beam. Wait…can you blow up a black hole?