I’m wondering if interstellar travel is possible. So I guess the starting point is figuring out FTL travel.
In: 1302
To have something to move at the speed of light you need that thing to be as light (mass) as a light particle (or a wave, it is still disputed). And to be faster it has to be even lighter. Then you need to think about what force is needed to be generated to achieve that speed and who is going to make it.
The only possibility to travel great distances are wormholes. But who knows what discoveries will the physicists make in the future.
There’s lots of fun explanations here that are consistent with the math (the core rule of relativity is that the math is straightforward but the physical intuition is anything but), but my favorite one is this –
You can go as fast as you want; there is no limit. The problem is that, the more you accelerate, you also accelerate *through time*. You could get on a hypothetical spaceship and keep accelerating until you reach the other side of the galaxy in a couple of hours. The problem is that, once you arrived there, you would find yourself about 100,000 years in the future. In its own reference frame, light travels **infinitely fast** – that is, no time elapses when you are “moving at the speed of light”. To the stationary observer, this looks like there is a “speed limit” since more and more of your speed is actually into the future rather than through space.
There’s no reason it’s the exact number that it is. That’s just the speed limit of the universe.
AFAIK, mass can’t go faster, but space time itself can. Hence why some warp equations actually work in theory.
Light is energy and has no stuff attached to it. Stuff weighs things energy doesn’t. Basically anything that weighs something is too fat for ftl
We don’t know.
The answers here are focusing on our attempts to understand what we observe about how light travels, and how things interact in our universe.
But the bigger question is, why does light travel the speed it does, rather than a different speed?
We have zero idea about that. Not even a theory or any math.
We may never know. Or we might be able to manipulate whatever makes the universe the way it is. That might make FTL possible, or it might mean the concept of FTL isn’t relevant.
For now, the answer is, we don’t know.
Interstellar travel is perfectly fine without FTL. It’s slow, but even at a fraction of the speed of light, humanity could colonise the galaxy faster than the time it took us to spread all over Earth.
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