Posted on 08/07/2002 12:53:40 PM PDT by Darth Reagan
Wow... Looks like not only have they debunked Einstein, but they have also achieved time travel, having journeyed into the future to publish their findings.
I'll aways recall Davies" last words in his The Mind Of God:
"We were meant to be here."
Please forgive the question, but I have zero background in such matters. It just seems like a logical question...
Photons have no "rest mass". They are essentially zero-mass. In fact, objects with zero mass must travel at light speed.
E=MC2 does not say you can't reach lightspeed.
The Lorentz equations are the operable ones. They predict that the mass of a body increases without limit as "C" is approached. In essence, the energy you are putting in to "push" the object to go faster just gets soaked up in its increasing mass, not in velocity.
Photons have no mass, but the do carry momentum.
The reasons that light is affected by gravity is that light always follows "space-time geodesics". Ordinarily, such geodesics are "straight lines". Near a large mass (like the Sun or a black hole) the geodesics of space-time are not "straight" but bent by the gravitation of the body. Therefore light departs from a "straight line" and travels in a curve. This is because--in effect--the warping caused by the mass causes a curved path to be the "shortest distance" for the light to travel.
--Boris
I'll aways recall Davies" last words in his The Mind Of God:
"We were meant to be here."
I'll always recall God's Last Words to His Creation in Life, the Universe and Everything:
"We apologize for the inconvenience."
Ah, thank you! For both the science lesson AND the grammar correction! I have always mixed those two up...
Sorry, I overlooked this one... By "no rest mass," do you mean that they have no mass when "still"? If objects with zero rest mass must travel at light speed (and are therefore never "resting"), how do we know that they have no mass while at rest? Please tell me to shut up if I'm annoying you with these simplistic questions :-)
The writing--I assume the reporter is a fault--obscures the message. Light does not absorb photons. Interstellar gas and dust absorb photons. Something like that seems intended.
They also applied another dogma of physics, the second law of thermodynamics, which Davies summarizes as "you can't get something for nothing."
That would be the first law. The second law is that entropy always increases in a closed system. ("You can't break even.")
What really bugs me is that the fans of Australian creationist Barry Setterfield (Mr. CDK) will be all over this thread claiming vindication. I see two possibilities. 1) This theory does not vindicate CDK. 2) This theory is a crock.
The "wrong type of photons"? I suppose this is the result of sloppy journalism, so common in accounts like this. But there must be more to it than we're told in this article.
The "rest mass" of a particle by definition is its mass as measured in its own frame of reference. For a photon, m = hf/c2, where h is Planck's constant and f is its frequency.
What's the frequency of a photon in its own frame of reference? In other words, how many wave peaks are passing you per second if you were travelling along side the photon? Zero, right? Therefore, the rest mass of the photon is also zero, theoretically.
Okay, someone who knows more physics than I do swat me down like a fly! :-)
BTW, here's a fun site that touches on lots of questions like that (e.g., see #126). My favorite is question #53: How much energy would be released if a marshmallow hit the Earth travelling 99.99% the speed of light (Answer: As much energy as in a "few dozen good-sized hydrogen bombs.").
I'm assuming you're combining E=hf and E=mc². The problem is that E=mc² doesn't apply to photons.
The general equation is E² = (pc)² + (mc²)² where p is the momentum. For a photon, E=pc; m=0 by geometry.
The problem with your analysis is that the principle of relativity prevents you from constructing--or even envisioning--a frame that is comoving with a photon. Light moves at speed c in all inertial frames; the moment you say that you are in an inertial frame, you are saying that light is moving at c with respect to you. Even in the limiting process where you approach the speed of light, the speed of light with respect to you does not go to zero. It remains fixed at c. Light itself does not have an inertial frame.
Question: But can't we envision being an observer photon moving alongside another photon?
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