i know one thing to have a complete vacuum you must have a sealed container and for certain electromagnetic waves to be conducted you must present one to....anyone see where im going??????
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Not a clue.
Welcome to Space.com. I'm afraid you'll have to make your posts clearer.
The first part is true if obvious, the second part is too incomplete to decipher the meaning...
Welcome to Space.com. I'm afraid you'll have to make your posts clearer.
The first part is true if obvious, the second part is too incomplete to decipher the meaning...
seeing how the affects of pressure and gravity are constant ,......couldnt that be an effect of a constant total vacuum.....(to seem expanding and lacking gravity)
jdubb_kyrapper":14fl5wgk said:
Sorry, but I have no idea what you are trying to say.
Maybe expand your thoughts a bit...
I don't see how a vacuum could in any way cause an expansion.
A vacuum is not a sealed container. A vacuum is simply the absence of everything. In order to create a vacuum in our atmosphere, you have to take out the matter, ie air. But in space, the vacuum already exists. That is why in movies when they open any doorway they fly out -- the pressure that is inside pushes everything outside -- to where there is no pressure.
The current size of the universe constrains the lowest frequency (and energy) possible for a photon to have. Obviously, as time passes, the lower limit diminishes.
This, curiously, eliminates a paradox of sorts.
As you increase the temperature of an object, the 'peak' radiation emitted progressively exhibits a shorter and shorter wavelength, but the body nevertheless, produces more photons of lesser energies too, and more and more of them as it is heated.
So, every object above absolute zero should radiate an infinite (yes, infinite) number of photons. Granted, most (funny word to use in regards to something characterized as infinite) will have vanishingly small energies, but still, there are an infinite (!!!) number of them.
As it turns out, though, photons with wavelengths greater than the size of the universe are inhibited from being formed in the first place. Colloquially, the impedance of the rest of the universe is mismatched to accept them.
Funny thing is, how does a particle at some non-absolute zero temperature 'know' how big the universe is (instantaneously) so as to appropriately inhibit is emissions ??
Me thinks the photon needs to 'know', at the instant of it's (possible) formation, just how big the universe is, and if it didn't, the universe we are in would not function properly for matter and energy (and life!) to exist.
Another anthropic principle thingy rears it's ugly head . . . .
This, curiously, eliminates a paradox of sorts.
As you increase the temperature of an object, the 'peak' radiation emitted progressively exhibits a shorter and shorter wavelength, but the body nevertheless, produces more photons of lesser energies too, and more and more of them as it is heated.
So, every object above absolute zero should radiate an infinite (yes, infinite) number of photons. Granted, most (funny word to use in regards to something characterized as infinite) will have vanishingly small energies, but still, there are an infinite (!!!) number of them.
As it turns out, though, photons with wavelengths greater than the size of the universe are inhibited from being formed in the first place. Colloquially, the impedance of the rest of the universe is mismatched to accept them.
Funny thing is, how does a particle at some non-absolute zero temperature 'know' how big the universe is (instantaneously) so as to appropriately inhibit is emissions ??
Me thinks the photon needs to 'know', at the instant of it's (possible) formation, just how big the universe is, and if it didn't, the universe we are in would not function properly for matter and energy (and life!) to exist.
Another anthropic principle thingy rears it's ugly head . . . .
Could you supply a site that discusses the minimum energy possible for a photon. I have not heard of this and it seems interesting - quick google didn't help me...
Yes we need a container to maintain a vacuum close to Earth sealevel, but that is because Earth has a moderately strong gravity well. A container is not needed in space, so I think your hypothesis is flawed. Low frequency photons, have only moderate loss, due to Earth's atmosphere. While space has a few particles per cubic meter, (imperfect vacuum) attenuation = absorption of photons of all frequencies is close to negligible for distances to several billion light years. We can detect frequencies of less than one hertz coming from space and have good reasons to think a trillionth of one hertz is arriving continuously. Detection is expensive as antennas less than one trillionth of a wave length, are very insensitive.
My guess is a few photons are generated by galactic groups, with wave lengths exceeding one light year, and these will eventually travel in approximately a straight line until they are well beyond the boundary of the portion of the universe that we can observe.
I don't think anything produces an infinite number of photons, but the number is very large, and perhaps larger for low energy, long wave length photons. Does any one know the number of photons produced per second, by a LED that produces one milliwatt of white light? Neil
My guess is a few photons are generated by galactic groups, with wave lengths exceeding one light year, and these will eventually travel in approximately a straight line until they are well beyond the boundary of the portion of the universe that we can observe.
I don't think anything produces an infinite number of photons, but the number is very large, and perhaps larger for low energy, long wave length photons. Does any one know the number of photons produced per second, by a LED that produces one milliwatt of white light? Neil
vogon13":2xqn01q0 said:
Wave - particle duality is a PITA isn't it. A photon whose wavelength is something akin to the size of the Universe isn't made in an instant. It's a long time in making. And as to the infinite number of photons, isn't is infinite is it ? The number will be related to the energy remaining in the object. When it's temp = temp of the Universe's background then photon emission will stop ... or perhaps it's slowed to the point we can't measure it.
origin":1j8db0zg said:
I'm guessing he's saying that the lower bound on a photon's wavelength is roughly the size of the observable universe, so on the order of 10^27 meters or so, corresponds to a frequency of about 10^-19 Hz and an energy of 10^-52 J or 10^-33 eV (Wolfram|Alpha ftw!). It's not a minimum energy possible in the quantum sense, but a cosmological limit on a photon's energy. I don't think it's particularly useful, though....
Is there a name for this paradox? That would help google search greatly, because I am also interested.vogon13":88dbia6c said:
So is the highest wavelength possible the diameter of the universe? or could you have a partial wave (say a third of the way from one crest to another)?
This may be a really stupid question, but that's never stopped me before. :roll:
Could the size of the universe constraint on the lowest frequency of photons be a reason why there is a lower limit to the temperature of matter that is above absolute zero? or is that just caused by uncertainty principle?
Also love the way you guys flipped the script, so to speak, on this thread. Started out with incomprehensible riddle, yet you still made it into an interesting read. 
Way to not waste a thread!
Way to not waste a thread!
I don't think very long wave length photons can know the size of the universe, or even the size of our Earth, so they are not restrained by the size of the Universe. That is not to say that infinitely long wave length photons are ever created. IMHO infinite does not occur in nature, so there may be a google of photons with wave lengths of more than one light year enroute in our galaxy, but not an infinite number. Neil
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