The missing matter of the universe: Dark Matter...

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Re: The missing matter of the universe: Dark Matter...

Postby savaughn » Fri Nov 17, 2006 10:03 am

Actually, if you can prove a massful photon, you've just disproven relativity, so yes... Einstein would be a loser in that scenario. Mass increases with velocity with a limit of c, blah blah blah. A massless photon is required for both e=mc^2 and for the speed of a photon to be c.
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Re: The missing matter of the universe: Dark Matter...

Postby The Gunslinger » Sat Nov 18, 2006 5:45 pm

Not sure if that's true Sav. E=mc^2 might hold the answer to whether the photon has mass or not. And I'd hypothesize that it does have mass, based off of what I read on this site, particularly the 2nd picture. At least it has mass, plus the potential to convert into more mass, or it's pure energy that can convert into mass and vice versa.

Although the way Einstein puts it, it's either energy or mass. What if, energy is just the "building blocks" for mass? Wouldn't the building blocks have their own infintessimal amount of mass? Maybe part of the problem is that we just don't have the instruments sensitive enough to measure mass at such a small level yet.

Might as well post the relavent points here...
Quote:
The deep connection Einstein discovered between energy and mass is expressed in the equation E=mc . Here E represents energy, m represents mass, and c is a very large number, the square of the speed of light. Full confirmation was slow in coming. In Paris in 1933, Irne and Frdric Joliot-Curie took a photograph showing the conversion of energy into mass. A quantum of light, invisible here, carries energy up from beneath. In the middle it changes into mass -- two freshly created particles which curve away from each other.


The first photograph showing the creation of a pair of particles, revealed by the fog spots they make in passing through the wet air of a "cloud chamber." The two particles, curving apart under the influence of a magnet, were created in the annihilation of a particle of light (coming invisibly from below).

This photograph not only shows the conversion of energy to mass, but confirms Einstein's idea that a light-particle will yield up its quantum of energy all at once in a single burst.

Image Archives Curie et Joliot-Curie, Paris.
**********
To listen to Albert Einstein explain his famous formula:www.aip.org/history/einstein/sound/voice1.wav

"It followed from the special theory of relativity that mass and energy are both but different manifestations of the same thing -- a somewhat unfamiliar conception for the average mind. Furthermore, the equation E is equal to m c-squared, in which energy is put equal to mass, multiplied by the square of the velocity of light, showed that very small amounts of mass may be converted into a very large amount of energy and vice versa. The mass and energy were in fact equivalent, according to the formula mentioned above. This was demonstrated by Cockcroft and Walton in 1932, experimentally."
**********

I'm guessing that atoms (matter) are just organized, or structured, pieces of energy. That site also references experiments to prove that E=mc^2 is true by converting mass into energy, by smashing atoms. The leftover mass after the collision was less than the original quantity, because the missing mass was converted into energy. The energy released was measured accurately enough to correspond to what E=mc^2 tells us what should have been released. Very interesting.

So what if the "missing mass" of the universe, or Dark Matter, is missing because of the Big Bang? The mass was converted into a ginormous (yes, ginormous :) ) amount of energy, expanded throughout the cosmos, and all the matter we see will continue to expand forever? Or is the total amount of matter expected was based on the theory that all the matter of the universe is expected to collapse, only to go into another big bang, and so on...?

Lastly, what is the unit of measurement for energy in E=mc^2? Is it quanta
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Re: The missing matter of the universe: Dark Matter...

Postby savaughn » Sun Nov 19, 2006 12:17 am

So you're missing the way the limit works, Lou. If a photon has mass (any mass at all) then there are a number of things that fall immediately out of that.

a) It's speed isn't a fixed c in all inertial reference frames.
b) It's speed isn't even constant as it would vary with frequency.
b) It's speed can approach, but never reach c.

Photons aren't really the building blocks for mass. They're more like the bike messengers for mass. The one that's really going to kill you is that photons have momentum. 9th grade newtonian physics is going to scream that they can't do that without mass either but thermal equilibrium has no problem with a massless photon carrying momentum.
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Re: The missing matter of the universe: Dark Matter...

Postby -The Fabulous Orcboy » Mon Nov 20, 2006 12:05 am

Yes, 'matter' is basically energy in 'solid' form.

But photons aren't energy, they're *carriers* of energy. I like Sav's analogy: "bike messengers for mass" :)

=====

Quote:
So what if the "missing mass" of the universe, or Dark Matter, is missing because of the Big Bang? The mass was converted into a ginormous (yes, ginormous :) ) amount of energy, expanded throughout the cosmos, and all the matter we see will continue to expand forever? Or is the total amount of matter expected was based on the theory that all the matter of the universe is expected to collapse, only to go into another big bang, and so on...?
Dark Matter was proposed based on observational evidence taken from the motion of galaxies in clusters -- their orbits could only be explained by positing MUCH more gravity (and thus mass) than could be otherwise detected. Since it couldn't be detected otherwise, it was called 'dark' matter.

The "ginormous" amount of energy, expanding throughout the cosmos, is Dark Energy, not dark matter.

The current theory is that, yes, we expect the universe to continue expanding indefinitely, and never collapse.

====

BTW: if you read the Wikipedia entry, it has a fairly straight-forward summary of proposed hypotheses about the constitution of Dark Matter, etc
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Re: The missing matter of the universe: Dark Matter...

Postby The Gunslinger » Mon Nov 20, 2006 3:44 am

Ah, yes, but Wikipedia doesn't talk back like you guys. ;) Thanks
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Re: The missing matter of the universe: Dark Matter...

Postby mattbird » Mon Nov 20, 2006 3:47 am

can you guys stop talking about science, and go back to flaming each other? thanks
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Re: The missing matter of the universe: Dark Matter...

Postby VectorAWX3 » Mon Nov 20, 2006 3:51 am

Screw you Birdoff! You hippie-haired dog-walking tofu-eating m***r-f***er! :p
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Re: The missing matter of the universe: Dark Matter...

Postby The Gunslinger » Mon Nov 20, 2006 3:52 am

BTW, Sav, I didn't specifically say that photons might be the building blocks of matter. I said energy.

EDITED: well, and I was wondering about this the other day, out of all the rays, x-rays, gamma rays, radio waves, light from the visible spectrum, etc, are photons only found in light waves?

Also, Sav, different colored photons have different frequencies, but whenever we talk about the frequency of light, you say that the frequency can't change because otherwise it would indicate mass. Do I understand this correctly? If it's right, can you change a red photon into a blue photon by changing the frequency
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Re: The missing matter of the universe: Dark Matter...

Postby mattbird » Mon Nov 20, 2006 4:05 am

hippy hair? you must have me confused with andy. or ken. or 1984 Keleher..
jer732 wrote:Birdoff makes me want to rage quit life
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Re: The missing matter of the universe: Dark Matter...

Postby The Gunslinger » Mon Nov 20, 2006 4:08 am

Plus, nobody answered one of my questions: what's the unit of measurement for energy in E=mc^2? Is it quanta
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