I suspect, much of the confusion is some of us think theoretical science and others enginering. If black holes have layers inside, they have lots of parts, but most agree, the extreemly small singularity at the center and the usually much larger event horizon. The event horizon does have volume, and mass inside, and large diameter . In my humble opinion nothing magical happens just inside a large diameter event horizon. Large event horizons have ordinary matter just inside the event horizon in the view point of the observer just inside the event horizon. If we could build a probe to travel to the event horizon of a large diameter event horizon it could even relay data back to Earth, by using multiple relay satellites.The data rate would however be much reduced due to time dilation IMHO
Large diameter event horizon = more than one million miles. Very small event horizon = one nanometer in diameter if there are any low mass black holes. Neil
Some of you may recall the discussion on escape velosity. The number depends on the starting point, and how long we accelerate at what rate of accelleration. and the point you are escaping to. Also the gravity strength and direction along the path of travel, including the starting and finishing point. Some of us concluded the escape velosity is not a useful number, without a long explanation. In like manner the radius of the event horizon varies at least a little depending on what is trying to escape from where to where. Neil
neil wrote:Some of you may recall the discussion on escape velosity. The number depends on the starting point, and how long we accelerate at what rate of accelleration. and the point you are escaping to. Also the gravity strength and direction along the path of travel, including the starting and finishing point. Some of us concluded the escape velosity is not a useful number, without a long explanation. In like manner the radius of the event horizon varies at least a little depending on what is trying to escape from where to where. Neil
I think that the escape velocity could be calculated as the speed at which your kinetic energy equals the negative potential energy of an object at the Earth's surface, in which case it would be independent, or virtually independent of these other factors.
Neil,
An example of a new force without energy is an elastic collision. You can argue that their is no such thing as a perfectly elastic collision, but the important point is that energy is not a function of force. There is no direct relationship of the type needed in the arguments of these threads.
Also a quick correction on escape velocity. Escape velocity does not depend on what "point you are escaping to". What you are esacaping is a closed orbit. Of course you can never "escape" a gravitational field, but with a large enough velocity you will be constantly decelerating, but never return.
Oops, I posted my explanation before I read Brandon's post. He says it much more succicntly than I did.
Escape velocity is a very important value when we are talking about black holes since it defines the event horizon.
