Relative light speed

[RascalPuff]

There are as many optical or 'event' horizons (radii from point of observation to event horizon parameter) as there are locations in space.

There seems to be a lot of misunderstandings about this.

The wielder of a flashlight anywhere in space is moving at the speed of light relative to surroundings.

The flashlight beam is projected at the speed of light, no matter where the light beam is projected from.

The speed of light is relative to the source from which it originates.

Any questions, contentions or further qualifications of this submission are invited.

Best regards,
- RP

[Graybeard]

There are as many optical or 'event' horizons (radii from point of observation to event horizon parameter) as there are locations in space.
There seems to be a lot of misunderstandings about this.

What is an event horizon. There are 3 horizons ... not counting our cosmic horizon.

The Absolute horizon, the Event horizon and the Apparent horizon.

Of these three the absolute and event seem to be similar, but what is the apparent?

The notion of an apparent horizon begins with the notion of a trapped null surface. We take a (compact, orientable,
spacelike) surface, and find its outward pointing normal vectors. The basic picture to think of here is a ball with
pins sticking out of it; the pins are the normal vectors.

Now we look at light rays that are directed outward, along these normal vectors. The rays will either be diverging
(the usual case one would expect) or converging.

Intuitively, if the light rays are converging, this means that the light is moving backwards inside of the ball. If all the rays around the entire surface are converging, we say that
there is a trapped null surface.

We can take the set of all such trapped surfaces. If we are thinking in terms of a simple Schwarzschild black hole, these surfaces will fill up the black hole. The apparent horizon is then defined as the boundary of these surfaces
— essentially, it is the outermost surface of the black hole, in this sense. Note, however, that a black hole is defined with respect to the event horizon, which is not always the same as the apparent horizon.

How can Light waves that are directed outwards be moving 'backwards' inside the ball ?? I understand how the light waves are diverging see italics above, but can't 'picture' the converging. Does anybody understand this and can you elucidate it ?

The wielder of a flashlight anywhere in space is moving at the speed of light relative to surroundings.

Don't you mean the beams from the flashlight are moving at the speed of light ?

The flashlight beam is projected at the speed of light, no matter where the light beam is projected from.

Gottcha ... LOL

The speed of light is relative to the source from which it originates.

What is this saying ... isn't it the same for all observers ?

Any questions, contentions or further qualifications of this submission are invited.

Please explain the different horizons, if not you Rascal, then anyone ?? Neutralino ??

cool bananas ... greg

[RascalPuff]

Hey Mr. Neutralino: Might you proffer your expertise in these issues? Greg has introduced some factors that I hope you can shed some light on, you may form a platform, before I make my next effort. Frankly, Greg has introduced some factors that I'm not familiar with. Anyone wish to share some resolutions on these issues?

Best regards,
- RP

What is an event horizon. There are 3 horizons ... not counting our cosmic horizon.

The Absolute horizon, the Event horizon and the Apparent horizon.

Of these three the absolute and event seem to be similar, but what is the apparent?

Beats me, Greg, I know of only one so called event horizon, and that there are misunderstandings regarding the absolute speed of light, relative to it.



How can Light waves that are directed outwards be moving 'backwards' inside the ball ?? I understand how the light waves are diverging see italics above, but can't 'picture' the converging. Does anybody understand this and can you elucidate it ?

"How can Light waves that are directed outwards be moving 'backwards' inside the ball?"

I don't know of any such backwards moving light relative to the issued horizon, Greg.

Don't you mean the beams from the flashlight are moving at the speed of light ?

Yes.

Gottcha ... LOL

What is this saying ... isn't it the same for all observers ?

In the issue at hand, the relative speed of light is exceeded at the optical horizon, as it relates to the location of the observer. So there's some apparent ambiguity, here.



Please explain the different horizons, if not you Rascal, then anyone ?? Neutralino ??

I know of only one optical/event horizon - that having to do with Hubble's law. The 'absolute' and 'apparent' horizons - I'm not sure how they're differentiated or what that means.

cool bananas ... greg

[neutralino]

Apparent horizons are normally mentioned when discussing the formation of black holes. See here for some brief comments. The important difference between an absolute and an apparent horizon is that just because a particle is outside the apparent horizon at some moment in time, does not mean that it will be able to escape the black hole.

Note that the terms 'event horizon' and 'absolute horizon' are usually synonymous.

I'm on vacation at the moment, so unfortunately can't answer in detail. I'll get onto it in the new year when I'm back home.

[MJA]

If I am a wielder of a flashlight traveling backward or in the opposite direction of the flash light's pointed direction, and traveling at the speed of light; would the flash light illuminate or emit light when turned on?

=
MJA

Answer me that one Batman!

[RascalPuff]

If I am a wielder of a flashlight traveling backward or in the opposite direction of the flash light's pointed direction, and traveling at the speed of light; would the flash light illuminate or emit light when turned on?

=
MJA

Answer me that one Batman!

Hey MJA, good to hear from you.

Until further authoritative notice, the answer to your question is affirmative.

Flashlights moving at relative speeds of light, both frontwards and backwards, are being wielded all the time, most everywhere flashlights are wielded.

Best regards,
- RP

[Graybeard]

Apparent horizons are normally mentioned when discussing the formation of black holes. See here for some brief comments.

I'm on vacation at the moment, so unfortunately can't answer in detail. I'll get onto it in the new year when I'm back home.

That is one really good sight Neutralino .... especially the clickable map

click here for really good map

Thanks ......... greg

Secondly .... What the hell makes you think we pay moderators to go on vacation ... did you ask first ?? .....