Dark matter - one mystery solved

[Lapin Dormant]

In these forums, this page seems to offer something .. .. .. I'll go post there, perhaps.

 

[Turbot]

I was pointing out that the night sky is a powerful heat sink. Any astonomer can explain this to you. A telescope pointed at the dark sky will cool far more rapidly that you would expect by considering the ambient temperature alone. This is pretty basic.

This is pretty wrong. The "night sky", as you're describing it, does not absorb radiation from the telescope, the telescope just emits the radiation and gets no feedback from its environment. In this sense, the night sky is not a heat sink, but rather the lack of a heat source. Any object left to itself will cool with time because it radiates its energy away. If, at the same time, the environment is giving feedback in the form of radiation, then the cooling process will be slower. That's why your telescope cools more slowly when pointed at a radiating source.

The telescope is radiating EM to the night sky and is receiving EM from the night sky. The difference is that the net exchange results in the temperature of the 'scope going down very quickly - radiative cooling. The scope will cool much faster if it is pointed at the night sky than if it is left sitting out in the cold with a dew cap on or without a dew cap, but pointing at a building, a row of trees, etc.

Not true. The EM need only be absorbed once and emitted once to produce a black-body spectrum based on the temperature of the emitter. An object can exhibit a black-body spectrum at one temperature, and then can exhibit a different (based on its temperature) black-body spectrum after being heated or cooled to a different temperature.

I think you need to pick up a good book on statistical mechanics. Equilibrium is not obtained as a result of one event, but is instead the end result of the many complicated interactions in a body (photon absorptions, collisions, etc.). An electromagnetic wave that is emitted from, say, the sun, will impact on the surface of a body (for example, you) and deliver energy to your surface. The particles on your surface will then have higher energies than the particles in your interior. However, because of collisions, vibrations, photon exchanges, etc., the energy will be redistributed throughout your body. A process like this can take a split second, a year, a millenium, or it might not occur at all. We can, however, calculate the approximate time for this process to occur and determine that the early universe should have had no trouble obtaining thermal equilibrium.

You missed my point entirely. The complexity of the reactions by which a blackbody attains its temperature has no relation to the spectrum of its radiation. If it is a true blackbody, its spectral curve is defined, and that curve will look the same no matter how many interactions and energy transfers caused the blackbody to have its current temperature, and no matter what the wavelength of the EM that heated it to its current state.

 

[SpaceTiger]

Sorry for the imprecision (I left you a pretty good opening there) - when I said that "empty" space is a pure black body, I pute quotes around empty because as the Hubble deep-field exposure show us, it will be impossible to find any direction in space from which we are not receiving radiation from embedded sources in addition to the background temperature of space itself (no matter how slight).

We do indeed see some light at every point that we look, but you can't simply say that the light is coming from space itself, you have to show it. Your argument as it stands right now is circular.

Well, I do know a "little" math. I also understand that if all the radiation that escaped during recoupling escaped at one time and at one average temperature, the redshifted spectrum of that source would retain its blackbody shape, albeit flattened with its peak shifted redward. The question I have arises from my understanding that in the BB model, recombination happened over a long period of time, with the plasma medium becoming more and more transparent to EM as time went on.

I already answered this concern in another thread, but you ignored it. I've noticed that you do that a lot. If you don't understand my explanation, then ask me to elaborate, don't pretend it didn't happen.

 

[Lapin Dormant]

Should one really be taking advice from a 25 year old, with 34 years of experiance?

Albeit an Intelligent 25 year old, but 35 years of experience in 25 years seems, well, way past anyones ability, even if they started at DAY one! there Birthday.

 

[SpaceTiger]

The telescope is radiating EM to the night sky and is receiving EM from the night sky. The difference is that the net exchange results in the temperature of the 'scope going down very quickly - radiative cooling. The scope will cool much faster if it is pointed at the night sky than if it is left sitting out in the cold with a dew cap on or without a dew cap, but pointing at a building, a row of trees, etc.

The only difference between this and your previous incorrect argument is that you allowed the night sky to radiate a little bit. I assure you that it still doesn't support your theory that the vacuum is absorbing radiation from the telescope and obtaining a temperature.

You missed my point entirely. The complexity of the reactions by which a blackbody attains its temperature has no relation to the spectrum of its radiation.

Well, of course that depends on how one defines "complexity", but the interactions have to be "complex" enough such that collisions occur throughout the entire gas and for a long enough time that the energy can be smoothly distributed. If these conditions are not met, the spectrum won't be a blackbody.

If it is a true blackbody, its spectral curve is defined, and that curve will look the same no matter how many interactions and energy transfers caused the blackbody to have its current temperature, and no matter what the wavelength of the EM that heated it to its current state.

Actually, no, that's not true. If I start with a blackbody at, say, 300 K, and change its environment such that it's not absorbing the same amount and/or spectrum of radiation, then its temperature will change. This transition takes a finite amount of time (sometimes a very long time) and, in the meantime, the spectrum of the body will not have the usual characteristic shape.

 

[SpaceTiger]

Should one really be taking advice from a 25 year old, with 34 years of experiance?

What "advice"? I'm showing him that his science is wrong. If you see a problem with my arguments, please share with us your wisdom. Otherwise, I don't see what that has to do with anything.

 

[Lapin Dormant]

I already answered this concern in another thread, but you ignored it. I've noticed that you do that a lot. If you don't understand my explanation, then ask me to elaborate, don't pretend it didn't happen.

That is advice, so please to help me, and any other reader{s} of this, tell me {us?} where you have previoulsy answered his question?

Thank you.

Have you ever done any studies of statistical propensities of Falsifications?

 

[SpaceTiger]

That is advice, so please to help me, and any other reader{s} of this, tell me {us?} where you have previoulsy answered his question?

https://www.physicsforums.com/showpost.php?p=781080&postcount=28"

Have you ever done any studies of statistical propensities of Falsifications?

Say huh?

 

[Lapin Dormant]

Thank you.

The other part, no, no more on that, it is simply a sort of Hobby of mine, people studies, and analysis.