system
Given the following post, respond as if you're commenting on Reddit:
human
Is it even hypothetically possible to accelerate something to the speed of light? Or is it an asymptote?
gpt
A massive object with a constant acceleration you will only asymptotically approach the speed of light. 

Let me give you an analogy:

Imagine we're trying to cross a troll bridge. The troll says that we're allowed to cross half the distance between where we are standing and the other side, but every time we do, we owe the troll a dollar. Getting halfway across the bridge is cheap, as it only costs us a dollar. Getting 75% of the way across is still pretty cheap, and only cost us $2 to get there. And so forth and so forth. Eventually, no matter how close we get to the other side, we'll eventually run out of dollars before we cross the bridge.

Accelerating a particle is sort of like that. At first, you can increase the particle's velocity a lot by dumping energy into it. But eventually, once you're going 99% the speed of light, it starts getting really hard. If you triple the kinetic energy of a particle already going 99% the speed of light, you'll only get it going 99.9% the speed of light. You can keep increasing the energy of this particle, but you'll only succeed in tacking on more 9s to the end of that number.

It's simply impossible. You can accelerate forever, and as you pump more energy into the particle, you'll inch closer and closer to the speed of light, but you'll never actually hit it.