Blip, how is it "off-topic" to mention that an FTL particle could well be able to escape from a collision with a black hole (because c is the escape velocity from one)? Perhaps you are playing on my use of the term, "ftler" to describe those who believe in ftl travel. In that case, just rephrase the posts so that the "personalised", "ftler" term is replaced by "supporters of ftl". It's difficult to have a debate when I get my posts arbitrarily deleted, because a mod doesn't like a word, or thinks that it is some kind of side-swipe at him/her.

EDIT: I was just trying to point out that belief in ftl is inconsistent with belief in the impossibility of ecape from a black hole.

The event horizon of a black hole is where the escape velocity is equal to the speed of light. Inside the event horizon, the escape velocity exceeds the speed of light (source).

SkyMutt wrote:The event horizon of a black hole is where the escape velocity is equal to the speed of light. Inside the event horizon, the escape velocity exceeds the speed of light (source).

This is exactly what I was going to say as I was reading through the posts, it's that simple, it's by definition, and so implies David knows of rockets that can accelerate to velocities beyond the speed of light.

SkyMutt wrote:The event horizon of a black hole is where the escape velocity is equal to the speed of light. Inside the event horizon, the escape velocity exceeds the speed of light (source).

Yeah, that's what I was trying to get at before. I think he understands what defines the event horizon but he thinks it's due to light being a vector quantity and no one before thinking 'what if it went the other way??'.

It's wrong from the start though because the speed of light is a SCALAR quantity, so it does not matter which direction a photon is travelling it will not escape, it's accounted for in the definition. So you're right that by definition nothing can escape after the EH. It does not matter if something is capable of changing direction, it's not a normal body in the sense where 'free falling' objects can change their velocity to be equal to or greater than the free fall in the opposite direction, by definition this can't be true.

If I were falling into a black hole and pointed a laser directly toward you and then as soon as I passed the event horizon changed the orientation of the laser to instead point it directly at another person no one would see the change. Ever. (well immediately, perhaps information that goes into a black hole is retrievable at some point in the future or something).

The vector of the photon does not matter. By definition this must be true. (AFAIK)