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daev
Post Laureate
Reged: 03/10/04
Posts: 3484
Loc: On the edge of the desert
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Post deleted by daev
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"Yes, I know it's flat here. When the seeing is good you can stand on your toes and see Chicago...."
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10022
Loc: Chaville, France
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Light waves don't need a substance to transfer through. Acoustic waves (sound, ripples on a lake) do. You will notice that when a photon travels, it's a single photon. When a ripple moves across a pond, it's not the same water traveling all the way to the shore - water shoves water which shoves water. Which explains why vacuum blocks sound but not light.
Off topic:
I remember a disastrous but hilarious high school experiment, where you put a flashlight and an alarm clock in a glass vacuum chamber. You know the deal: once the vacuum is made, you are supposed to see the light but not hear the clock. First we could hear the clock because the vacuum was not made. Then the light went off. Then everything was as planned but once the air came back in the chamber we could still not hear the clock! Oh well.
As for the quantum creation of matter, it is not a prediction, it's a fact. Matter and antimatter get created spontaneously and annihilate in a flash of light almost right away all the time; the "light" has a wavelength I learned to calculate in high school. And people who use some sort of spectroscope / photometer combo in different areas of research (I know my father used it in mining but I don't really remember why) have to filter it out.
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Matt
CI700 mount with various scopes on top.
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moynihan
Carpal Tunnel
Reged: 07/22/03
Posts: 1517
Loc: Wisconsin
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Quote:
As for the quantum creation of matter, it is not a prediction, it's a fact. Matter and antimatter get created spontaneously and annihilate in a flash of light almost right away all the time;
One of the bizarre things about that is if this would happen "near" a black hole, then one particle may be captured by the black hole, and the other, not, resulting in what is called "Hawkin Radiation". Do not know if that has been confirmed yet or not, Hawkin & Penrose worked that out in mid-80's i think.
jay
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"Gosh, you've... really got some nice toys here"
Dual mount/ambient temperature Hominid Widefield Photon Collectors®
Pleistocene™ ˝ watt Wetware Integration Unit.
entia non sunt multiplicanda praeter necessitatem
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Jim Svetlikov
Carpal Tunnel
Reged: 10/06/03
Posts: 2033
Loc: Crescent Beach
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Hawking Radiation is one of those theories which have yet to be based on observation or experimentation. It looks good on paper.
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It is better to build a boy than try to mend a man.
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rboe
Numbfinger
Reged: 03/16/02
Posts: 39760
Loc: Phx, AZ
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I think it has legs, but to design an experiment to test it, you have to be very clever.
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Ron
NS11GPS
Pronto
16" dob
15X70 Obies
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matt
Vendor (Scopemania)
Reged: 07/28/03
Posts: 10022
Loc: Chaville, France
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It's good on paper because it's not something 'invented', it's a consequence of accepted laws of physics. It's not one of those theories where you need to set up another theory, modify an existing one and invent three new types of quarks to have it standing.
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Matt
CI700 mount with various scopes on top.
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Anonymous
Unregistered
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Quote:
As for the quantum creation of matter, it is not a prediction, it's a fact. Matter and antimatter get created spontaneously and annihilate in a flash of light almost right away all the time; the "light" has a wavelength I learned to calculate in high school.
What phenomenon are you talking about? I don't know much about spontaneous creation of a particle/anti-particle pair, but if they annihilate the energy should go back into the quantum fluctuation. If it emits a detectable flash of light, where is that photon energy coming from?
Quote:
And people who use some sort of spectroscope / photometer combo in different areas of research (I know my father used it in mining but I don't really remember why) have to filter it out.
Are you talking about the 511 keV annihilation line? If so, the positrons responsible for those are not created "spontaneously." It is usually created by having a >1.22MeV photon collide with an atom. (It has to collide. If a photon changed into particles mid-flight, you violate the conservation of momentum.)
Edited by Ken_K (04/30/04 01:09 PM)
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Jim Svetlikov
Carpal Tunnel
Reged: 10/06/03
Posts: 2033
Loc: Crescent Beach
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Matt
Are you referring to "pair production?"
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It is better to build a boy than try to mend a man.
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