Correct me if I'm wrong, but from my understanding, it's only impossible for an object with mass to accelerate to the speed of light. If something was magically accelerated to above c, it wouldn't break any rules to stay above c.

So what would happen in a collision between a slow object and something moving faster than c?

Thats easy!
boom.

My guess is that faster than light and slower than light matter interactions are impossible.

So they would never interact, kind of like the way that a radio wave can slide directly through a sheet of metal.

Assuming that it did actually interact, I imagine the only reasonable outcome would be the spontaneous creation of a horde of naked singularities which would then almost immediately scab over into a plethora of black holes.

I didn't think it was possible to go faster than light

Allowing the magic part, the kinetic energy equation still applies. So fast velocity minus the slow in that direction. Might as well have been going a bit slower than light. A grain of dust at even a small percentage of light has a lot of energy.

Add to my guess that I think relativity might rear its head in this and say that even if it was going that fast, it would only appear to go less. Same reason why light is seen to go at c by all observers, no matter the frame of reference. There's equations for that.

Yeah, no interaction at all is my best guess as well. Tachyons are the realm of some pretty weird shit. (And they probably don't exist at all.) Imaginary mass and all that.

There is no such thing as faster than c. From the POV of a photon, the distance to its destination (no matter how far) is zero - it's already there in literally no time.

You can't go faster than that.

What happens when something traveling at the speed of light (ie: EM radiation) hits something going slower than the speed of light?

The answer there is: it depends, because the issue isn’t relative velocity but energy density and transfer.

I guess that would still be something like this

Time would run backwards for the seemingly faster thing, but forward for the other thing.

There's a movie about exactly this question: 'Tenet' but I'm going to watch it only next week 😇

I watched that movie in the past. I don't remember any of it.

I will watch it for the first time next year. I enjoyed it very much!

Hold on! That's when I watched it! But not yet.

?yllaer ,uoy diD

Not with that attitude.

This was funny when I read it tomorrow morning last week.

Big badda boom.

I don't remember rebmemer t'nod I

I haven't studied this in a while and do not work in the field, so this might be incorrect or imprecise.

It is not only impossible to accelerate to the speed of light, it is impossible for anything to have a speed higher than the speed of light.

While it is counter intuitive, even relative speed cannot be higher than the speed of light. If you are on a train going 300 km/h and another train is going the opposite direction at 300 km/h, then that other train, from your perspective, is going at (almost) 600 km/h.

But when we get close to c, things change: if in a referential, you are in a spaceship going at 0.9c, and you observe a photon going at c in the opposite direction, from your perspective, that photon is going at c for you, in the spaceship, and it is also going at c for someone stationary in the referential observing from the outside.

Similarly, If you are in that spaceship, and observe a spaceship going in the opposite direction at 0.9c as well, then you won't observe them as going 1.8c in your referential, but something close to yet below 1c. I forgot the formula.

Nothing can be faster than light, in any referential.

I'm not a physicist, but I have heard this before.

I think it's because people see that the lorenz factor has an asymptote, and so commonly math comes back after an asymptote.

But the denominator is a square root, so there is nothing after the asymptote.

Maybe also inspiring the TNG warp curve, where warp 5 was so much easier than say 4.99.

Anyway, as far as I know there is no theory of anything FTL.

The kinetic energy equation does not apply, because classical mechanics (including E~k~ = 1/2mv^2^) only works for scenarios much slower than c.

in relativistic scenarios you have to use Einstein's math. That involves multiplication by the Lorentz Factor 1/√(1-v^2^/c^2^). Solving for any velocity larger than c results in taking the square root of a negative number, which means that the kinetic energy of a superluminal object is literally imaginary (in the mathematical sense).

Valid point. We'd never be in the position anyway because we've already used "magic" to create the possibility.