We’re taught from the start that it means that faster than light (FTL) travel isn’t possible, right?
Wrong. That’s not actually what it says. Let’s look at it in terms of component factors.
E = energy
m = mass (of the object in question)
c = the speed of light, squared in this case
Therefore, it states that the energy needed to move that object increases as the object approaches light speed. It also means that as an object approaches the speed of light, the mass will increase as well. In other words, things get very massive and compressed the closer to the speed of light they travel and it takes more and more energy to move them.
So what does this really mean? It means that we won’t break the light barrier using conventional rockets and propulsion systems. Most people take this to mean that faster than light travel is, and I loathe this word with a passion:
Hogwash. Cars that go faster than 25 mph and breaking the sound barrier were once also considered impossible, until both occured.
So what, then, does it mean for a feat to be impossible? It just means we can’t accomplish that feat today. Tomorrow could be another matter entirely.
E=mc² just tells us that when we do break the light barrier, it won’t be done by accelerating the craft to 186,000 miles per second.
Meaning that we just have to find another way to do it, and scientists are excellent at changing the rules as they make new discoveries. As Captain Picard once told Mr. Data, “Things are only impossible until they’re not.”
Impossibility is a temporary condition.
And the best way to change it?