Starship Asterisk*

saturno2 wrote:I think ( a hyphothesis), a black hole is not a "hole".
I think that in the center of a black hole there is a " black star" of
neutrons.
This "black star" of neutrons has more density, diameter, magnetic field
and gravity than a pulsar.
It rotates at high speed as a pulsar.
This " black star" is black because it does not emit radiation and
"light off" the photons

saturno2 wrote:In a black hole, the event horizon is an imaginary spherical
surface, through wich the particles fall into the hole only.
We can not see the state of matter in the center of this hole.
It is conceivable, within the possibilitles, that in the center of
a black hole, there is a black star of neutrons, denser than a pulsar

saturno2 wrote:Chris Peterson wrote:
The event horizon is not imaginary.
Wikipedia wrote:
"Event horizon in a rotary black hole
The event horizon is an imaginary surface of spherical form
surrounding a black hole"

saturno2 wrote:Wikipedia wrote:
"Event horizon in a rotary black hole
The event horizon is an imaginary surface of spherical form
surrounding a black hole"

rstevenson wrote:I see no harm in using "imaginary" to describe the event horizon. After all, we use imaginary numbers all the time in mathematics, so "imaginary" is not the same, at least in a scientific context, as "unreal." Events can be seen to happen outside the event horizon, and cannot be seen to happen within it. That's all the event horizon is. It's not a place in the usual sense, and may not even be steady and uniform. It exists only as a cusp within the mathematics used to describe black holes. Imaginary is therefore a fine word to describe it.

Rob

rstevenson wrote:I picture the event horizon using this analogy...

Take two magnets and place them near each other. Each will attract iron filings, as usual. But there is a "surface" between them which can be defined as the collection of all points where the magnetic force pulling filings towards one magnet is precisely balanced by the force pulling filings to the other magnet. Iron filings dropped near that surface will be attracted to one side or the other of it, eventually reaching one magnet or the other. We can use a suitable equation to calculate where that surface is, yet there is nothing there. We have to imagine it, hence it's an imaginary surface.

http://en.wikipedia.org/wiki/Event_horizon wrote:
<<A misconception concerning event horizons, especially black hole event horizons, is that they represent an immutable surface that destroys objects that approach them. In practice, all event horizons appear to be some distance away from any observer, and objects sent towards an event horizon never appear to cross it from the sending observer's point of view.

An observer crossing a black hole event horizon can calculate the moment they have crossed it, but will not actually see or feel anything special happen at that moment. In terms of visual appearance, observers who fall into the hole perceive the black region constituting the horizon as lying at some apparent distance below them, and never experience crossing this visual horizon. Other objects that had entered the horizon along the same radial path but at an earlier time would appear below the observer but still above the visual position of the horizon, and if they had fallen in recently enough the observer could exchange messages with them before either one was destroyed by the gravitational singularity. Increasing tidal forces (and eventual impact with the hole's singularity) are the only locally noticeable effects.>>

saturno2 wrote:Chris Peterson wrote:
" The event horizon is not imaginary. Neither is it a physical surface."
You are right
But the article is right, too. Why?

geckzilla wrote:I sort of understand how a moving observer could not see itself crossing an event horizon. But the stationary observer dropping the object in? What's that about?

Although you wouldn't notice anything particular as you fell into a black hole, someone watching you from a distance, would never see you cross the event horizon. Instead, you would appear to slow down, and hover just outside. You would get dimmer and dimmer, and redder and redder, until you were effectively lost from sight.

geckzilla wrote: Aquaporins and black holes. What a funny mix of things to have in my head.