Faster Than Light

Why can't anything move past the speed of light? --ConorT99

Let's start at slow speeds and work our way up.

One 100-millionth of the speed of light is about 6.7 miles per hour. This is between typical walking speed and typical running speed. Nothing weird happens here. One 10-millionth of the speed of light is 67 miles per hour, roughly the speed of a car on the typical interstate highway. One one-millionth of the speed of light is 670 miles per hour, slightly faster than an average passenger airplane. These speeds are quite common, but if you're in a car, you'll probably fly into the air at that speed.[1] One 100-thousandth of the speed of light is 6706 miles per hour. This is faster than most things made by man, including cars.^{[citation needed]} This is just shy of Mach 9, the speed of NASA's X-43. Even at Mach 3, aerodynamic heating causes temperatures of 500 Fahrenheit[2] , so Mach 9 would likely cause very high temperatures. If you're on earth at least. If you're not on earth...

One 10-thousandth of the speed of light is 67,061 miles per hour. This is close to the speed of the spacecraft Juno as it slingshotted around Earth.[3] Juno is one of the fastest manmade objects[4], so it's clear that we won't be getting anywhere near the speed of light using anything manmade. But who said anything about manmade objects?

I'll skip ahead to relatavistic speeds. Going at 90 percent of the speed of light, strange things start to happen.(Don't ask me why. Ask Albert Einstein instead.) Time dialation would be noticable. Spend 10 minutes at that speed and 20 minutes would have passed for the rest of the world. The Dopper effect would also distort the colors of objects towards the blue end of the spectrum.[5] The mass of an object approaching the speed of light would also increase significantly. A 1-gram object moving at 0.9c would have a mass of 5.26 grams.[6] This would be a problem for any object with substantial mass, since it would take an even larger amount of energy to get an object close to the speed of light than it otherwise would. Luckily, the universe is made full of very small and light things.^{[dubious-discuss]}

A hydrogen atom is pretty light, so it seems like a good particle to start off with. To be specific, a hydrogen atom's mass is one amu. An amu is 1.66*10^-27 kilograms and a hydrogen atom at 0.9999c would  have a mass of 5000 amu or 8.3*10^-24 kilograms. How much power would this take? The formula for watts is kg*m^2/s^3. An object sustaining this speed for one second would trvel 299,762.4788 kilometers. So, plugging in results in a power consumption of 2.48 femptowatts. We can do better. I'll throw in a few more nines. The people reading hypothetical science blogs really like lots of nines, don't they? A hydrogen atom moving at 0.999999999c would have a mass of 500,000,000 amu or 8.3*10^-19 kilograms. The power used would be a quarter of a nanowatt.
Let's try 0.9999999999999999999999999999999999999999999999999999999999999999999999c (I pressed 9 a lot of times just for the hell of it). This is so huge that my TI-84 Plus calculator gets a divide-by-zero error when I try to figure out the mass increase. So that means that there's an effectively infinite mass, which would take infinite energy to move at all. And we're still not even at the speed of light.

Lighter particles (such as neutrinos, the lightest known particles[7]) can get you closer, but they won't get you to the speed of light. To offset the fact that the mass of an object is infinite at the speed of light, a particle would have to have a mass of zero. Photons have no mass, but they still won't get past the speed of light, only to it.

To get past the speed of light, some laws of physics would need to be broken. (DISCLAIMER: If you break the laws of physics in your jurisdiction, I am not responsible)

With that out of the way, let's consider the idea of negative mass. In that case, a 1-gram object traveling at 1.01c would have a mass of -49.75 grams. The problem: negative mass does not exist.[8] But if it is ever created, then it could be used to build an Alcubierre Drive, which can travel faster than light.Come to think of it, if you're willing to break the laws of physics, building a working Alcubierre Drive would be a decent science fair project. Might even win first place.

But if you aren't prepared to take the risk of breaking the laws of physics, is there still a way to do this? Turns out there is! As you may know, light goes at different speeds through different materials. And if you cool sodium atoms down to near absolute zero, they become a Bose-Einstein condensate, and light would travel at a speed of 38 miles per hour.[9] So if you can get something to move as fast as a car through a vat of Bose-Einstein condensate...it'd be going faster than light.