Re: OT: Agnoticism (WAS: Making money from Java)



"charles hottel" <jghottel@xxxxxxxxx> wrote in message
news:64908$43acbfc1$4f9c609$19616@xxxxxxxxxxxxxxxx
>
> Well I have heard of the this concept but I do not pretend to understand
> it. At one time it was thought that space was filled with and "ether" but
> I thought that was disproved.

It was found to be unneccesary in order to explain the wave nature of light.

The question was: "If light is a wave, what is it that is waving?" We now
know that light is a both a wave and a particle ("wavicle" has been used...)
and behaves like whatever one you want it to.

No, really... :-).

If you do an experiment to prove it is a wave (Young's famous "two slit"
experiment - Richard Feynmann claimed that if you could understand this
experiement fully, you could grasp all of Physics), it will be found to be a
wave; if you do an experiment to prove it is a particle (Einstein received
his Nobel prize not for Relativity, but for showing that "particles" of
light could knock electrons out of certain metals and the emission of the
electrons depended on the wavelength and intensity of the light), it will be
found to be a particle. What is it REALLY? A continuous, self propagating,
interwoven, oscillation of an electric and a magnetic field, that has
certain probabilities of occurring, and can be fully described by 8
equations formulated by James Clerk Maxwell in the 19th century. No need for
"ether".

>Is this the new ether?

No.

>When I hear the word "virtual" I tend to think 'simulation' i.e. using one
>resource to simulate another. Maybe the universe is a humongous holodeck
>after all.
>
Maybe...:-). Maybe it is many things, depending on the observer. No one
really knows what matter and energy are doing when they are not observed...

> I was reading Scientific American at the doctors office today and they
> said these virtual particles appear in pairs. They think it is possible
> for them to pop into existence near the event horizon of a black hole such
> that one is sucked into the black whole and the other escapes. They called
> it the Hawking effect and said if it happened often enough that the black
> hole could evaporate.

Stephen Hawking and Roger Penrose did the seminal work on this. Hawking was
the first to question the idea that nothing could escape from a black hole.
He sums it up in his chapter "Black holes ain't so black". (See - "A Brief
History of Time") The separation of the particle pairs across the event
horizon of a black hole, as you describe, predicts that black holes should
"radiate". It is not yet established whether they do or not (as far as I am
aware), but my money would be on Hawking. His expostulation makes sense.

The black hole would not evaporate, it would explode in a burst of energy.
It is the negative energy of these virtual particles flowing into the black
hole that causes a loss in mass of the BH. As the mass of the BH decreases,
the event horizon gets smaller, but this decrease in the entropy of the BH
is compensated for by the entropy of the "emitted" radiation , so the second
law is never violated.

The lower the mass of the BH, the higher its temperature so, as it's mass
continues to decrease it gets hotter, faster. This causes more mass to leak
away (evaporation). What happens when the mass approaches zero is not
entirely clear but the best guess is a tremendous emission of the remaining
mass, in the form of a spectacular explosion.


> A lot of this is very hard to visualize and understand just from words. I
> am sure if a person can understand the mathematics that it is more precise
> but very hard to put into language. I do not understand how the universe
> has no center and no edges even in the past when it was much smaller.

It has an origin, which is kind of like a centre. As for no edges: Consider
a balloon inflating. It is not infinite, yet it is boundless. (There is no
boundary or edge, and you could wander all over it without constraint, just
like the planet Earth.)

> Also it is expanding but it is not into anything else.

That's right. It is the SPACE (and, along with it the time...) which is
actually expanding, not the universe expanding into space. It is very hard
for our three dimensional brains to imagine "no space" or even "curved
space", yet that is the reality of our universe. The Big Bang was not an
explosion that occurred in space; it was the creation of space and time
(which have been expanding ever since).

After Einstein gave a famous lecture about the curvature of space
(Relativity had predicted the warping of space by gravitational fields
asociated with matter - Matter tells space how to bend; space tells matter
how to move. The orbits of the planets are actually "straight" lines through
curved space...), a member of the audience is supposed to have said: "That's
all very well Professor, but if I go to the "edge" of this expanding space,
and stick out my umbrella, where is it?".

Einstein replied: "Sticking in the other side".

It's a bit like the infinite field of Space Invaders... as things disappear
off the bottom of the screen, they reappear at the top. (Similarly with the
sides.)

> I hope when I retire I can read more about this stuff.
>
Me too :-)

Pete.



.

Relevant Pages

  • Re: If my hypothesis were wrong, Hawking radiation would make no sense
    ... but a REPULSIVE gravitational field ... proportional to its inertial mass. ... particle-anti particle pairs near the event horizon of the black hole ... the black hole wouldn't lose mass, ...
    (sci.physics)
  • Re: [OT] Q re Hawking radiation
    ... > carries mass/energy away, reducing the mass of the hole by that tiny ... The particle and anti-particle must appear EXTREMELY close to the event ... The, let's say, anti-particle that falls into the black hole will eventually ... (mass conversion into energy). ...
    (talk.origins)
  • Re: If my hypothesis were wrong, Hawking radiation would make no sense
    ... proportional to its inertial mass. ... And Hawking radiation can be explained by the presence of virtual ... particle-anti particle pairs near the event horizon of the black hole ... the black hole wouldn't lose mass, ...
    (sci.physics)
  • Re: hawking radiation
    ... > how a black hole can radiate..& loose mass...... ... > falls into the black hole & the article is left out as radiation ... > Now the antiparticle falling in causes the mass of black hole to ... just as if it has been radiating a particle.. ...
    (sci.physics)
  • Re: Is light a wave or a particle?
    ... >> previously) that no particle can be totally massless, ... > Depends on if you talk about rest mass or relativistic mass. ... Relativists threw out the relativistic photon when they were ... because it is created from a moving light wave and a virtual particle. ...
    (sci.physics)