Posted on 04/03/2002 8:18:40 AM PST by Texaggie79
He meant they bashed American astronomy all day long, and then went home to the latest issue of "Ap-Jay".
"Another way of stating this is that outside of the event horizon all properties of the matter that formed it are gone except for the total mass-energy, rotation, and electric charge: this is sometimes called the Black Hole Has No Hair theorem."
Nor can I prove that Invisible Star Goats are NOT pushing the planets around the Sun, instead of reacting to the influence of the spacetime curvature (gravitation).
The point is that General Relativity is a Theory that fits all available evidence and which has survived all attempts at falsification. "Vortex" theories of gravitation notwithstanding, no other gravitational theory can make that claim.
The whirlpools that are drawn around black holes (as in the above illustration) are accretion disks. Accretion disks form because the infalling matter will, in all likelihood, have a nonzero net angular momentum. The angular momenta of the infalling objects all cancel each other in every direction but one (the axis of the disk). The matter left in the disk goes into orbit around the black hole.
The accretion disk of a black hole actually wouldn't look like a normal accretion disk as shown above. This is because light bends around the black hole, with the result that if you are looking at the near side of the disk almost edge-on, you'll be looking at the far side of the disk face-on. It looks sort of like a misshapen LP record with a 90-degree fold in it. (See an example here.)
Oh yeah? Well a lot of good it does 'em.
When a new theory supplants an old one, it is usually for a good reason.
The practical issue is that we have yet to find an instance where the current theory of gravitation gives an incorrect result. Hence, there is no basis for "vortex" gravitation (or any other theory) to replace it...... for the moment.
I have a great deal of trouble with Hoagland's stuff; latching onto the "Face on Mars" hysteria, combined with all his conspiratorial speculation he's into, really makes him sound like a lunatic rather than a serious scientist, which he once was.
<|:)~
Well, that ought to teach you to ask impertinent questions!
Just kidding.... you actually asked some pretty good questions, and there's a wealth of talent roaming around FR who can help explain some of these concepts.
Without folks like you ASKING the questions, nobody would bother answering them.
Or, in the immortal words of the founder of "Faber College" in "Animal House":
Didn't you know....... the act of asking a question in itself is grounds for the DSP status!
Respectfully Submitted,
Dean Wormer
I don't know if he was ever a scientist. He was certainly a science journalist and planetarium manager. He was very good, too. A scientist? No, not formally. But perhaps in spirit.
The Face on Mars is a joke, not for the purpose of having fun and playing with the gullible, but for encouraging people, meaning Congress and NASA, to let us all share in the exploration of our solar system.
Hoagland's subspace or hyperspace physics, or whatever title he gives it, is not his, he is the journalist. Although the mathematics of the day was not up to the task of dealing with the idea, it may come back, probably in an altered form suitable for computer modelling. Along those lines stay tuned for developments of the fifth dimension out of Princeton and watch for Nima Arkani-Hamed, who may have something to say later.
Speaking of Nima Arkani-Hamed, I had the pleasure of showing him around the physics department here at Penn a couple of weeks ago, when he was the colloquium speaker. His talk was entitled "Deconstructing Dimensions" (in an intentional jab at postmodern blather). While he's famous for proposing that there exist large extra spatial dimensions, in this talk he was talking about eliminating dimensions! The subtitles of his talk were "Extra Dimensions Suck" and "Destroy All Dimensions".
He's come up with a way in which field theories can dynamically generate "apparent" or "effective" extra dimensions that behave so much like the real thing, that the possibility can't be ruled out that there are fundamentally fewer than the four dimensions we believe ourselves to live in.
He even had some experimental tests that could distinguish between real dimensions and "theory space" dimensions. First we have to discover the graviton, though.
Indeed it is! :)
Hang around with this crowd and you'll get headaches frequently! LOL
Ok... for a standard telescope (approximately):
. resolution (theta) = 1.22 Lambda/Diameter
where theta is the angle of resolution,
Lambda is the wavelengh in meters
and Diameter is the telescope's diameter in meters.
So, the Hubble has an average wavelength (lambda) of half-micron, and a diameter of 2m. (rounded).
Then, if VLBI has an effective diameter (baseline) is 30,000,000 meters (30k km) and the wavelength is decimeter, then it would have 100 times the resolution of Hubble @ half micron wavelength and 2 meter diameter.
Works out to a good approximation.
Amazing... a radio telescope system with 100 times the resolution of Hubble....
Then imagine a visual interferometer system with Earth-moon baseline!!
Images of extra-solar planets.
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