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Cold Black Sun

  1. Mar 20, 2008 #1
    Hello All,

    Please excuse my ignorance. I have a number of questions about the sun.

    Space is cold, yes, very very cold, close to absolute Zero. I have heard the argument that it is solar radiation or through convection that the heat from the sun reaches us. However I still can't get my head around it. Given that it gets colder & colder the higher into the atmosphere you go, would it not be rational to conclude that it is in fact our atmosphere which is itself generating the heat by another means; i.e. converting the radiation from the sun into heat. If space is a vacuum, how does the sun burn? Is it not possible that, although emitting radiation, it could also be dark, our atmosphere also converting the suns energy to light. Pictures from space aside, which could be doctored, are we being lied to. Is the sun really cold & black; if not then why not; & why is this impossible?
  2. jcsd
  3. Mar 20, 2008 #2


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    Oh dear. I wonder if you have eyes in your head.

    Firstly, the sun is burning in a self-sustaining nuclear fusion reaction and does not need air, or anything else. Heat is radiant energy and travels through empty space to reach us here on earth. Perhaps you've noticed that it feels hot when the sun shines on you ? Or when you stand close to a fire, the fire heats you by radiation.

    And why would anyone bother to pretend the sun is hot if it were not so ? I think you should go to the library and get a book about the solar system with lots of pictures and do a little studying. This stuff is all well known - and it's not lies.
  4. Mar 21, 2008 #3
    Very good Mentz, but despite your patronising, unhelpful & surmising remarks you haven't answered anything I asked in my question.

    Despite insinuating I am thick; I am a fully qualified computer engineer, with qualifications as long as your arm, & I asked an intelligent question.

    Despite being "a self-sustaining nuclear fusion reaction" It is fire, is it not? How does fire burn in a vacuum? Saying it does doesn't answer the question.

    "Perhaps you've noticed that it feels hot when the sun shines on you ? Or when you stand close to a fire, the fire heats you by radiation."

    Perhaps you have noticed that you are in atmosphere when this happens? I would not feel it in space. Duh.

    I can think of multiple & possible reasons as to why the certain truths of the nature of the Sun & our solar system would be altered or kept quiet. You obviously haven't thought about any of this stuff, if you can't answer the question intelligently then don't bother; let someone else have a go. You have obviously accepted everything you have been told in your little picture books.
  5. Mar 21, 2008 #4


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    Mentz did answer the questions.

    Firstly, the nuclear fusion that causes the sun to generate heat (it is incorrect to say the sun "burns") is extrordinarily well understood, as is the process of radiative heat transfer.
    Here's a quick primer on black body radiation: http://en.wikipedia.org/wiki/Black_body

    You seem to be hung up on convection, but convection requires air and as you correctly pointed out, there is no air in space. Convection also makes heat rise, which means that standing in front of a fire, you don't feel any heat from convection - it all goes up and you have wind blowing at your back.

    The fact that radiation is the heat transfer mode is easy to see due to the fact that objects on the ground get much warmer than the air, thus it must be that those objects are transferring heat to the air and not the other way around. And there is no mechanism by which the atmosphere itself could generate heat.

    This quote is troubling:
    I would encourage you not to deal in conspiracy theory. Not only do we frown upon such discussions here, but it is not logical to believe that the millions of scientists are all invovled in some enormous conspiracy to hide the truth. Mentz accepts what he has been told because it is correct - and it should be easy to see why.

    Mentz's tone may have been slightly patronizing, but yours is extremely combative. There isn't much we can do to help you learn if you keep such a combative tone.
    Last edited: Mar 21, 2008
  6. Mar 21, 2008 #5
    Thank you for a little more of an answer, I never argued that the Sun wasn't emitting radiation, I was simply asking a question about the possibility & thought around the transfer of this said radiation into heat & light.

    I don't deal in conspiracy theory, although I am well read; If we all totally accept the theories & surmising of the present, & science is largely not a done deal; then where would we be? Probably still thinking that the World was flat & we would fall of it if we sailed over the edge, & believing we were centre of the Universe.

    I was perfectly appropriate in my reply. I am quite happy with my level & course of learning.
  7. Mar 21, 2008 #6


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    I'm going to step in here and see if I can smooth things out a bit.

    No, fusion is not fire. Fire entails combustion, usually involving oxygen, which does not occur in a star. Fusion is the combining of particles, with energy left over from the reaction. You can safely think of the sun as billions upon billions of nuclear bombs going off continuously.

    Wrong again. The side of you that's facing the sun would get unbearably hot; the other side would be frozen solid. The presence of atmosphere is what moderates and disperses the heat so you feel it more or less evenly under normal circumstances. It's not entirely effective in that regard, as you'll know if you ever fell asleep while tanning.

    That part really is combative. While Mentz's response was a bit brusque, this response was inappropriate.
    Last edited: Mar 21, 2008
  8. Mar 21, 2008 #7
    Fair enough I stand corrected then; as I said; I was merely asking a simply question about something which I had difficulty getting my head around. I am unaware of what a nuclear explosion would look like in space.

    I didn't expect to be treated like like some kind of retard who happened to fall across this forum, & replied to like I was a child by Mentz, if my response appeared combative, then I apologise.

    I did enjoy Physics at school, it was one of my favourite subjects, however since leaving I haven't researched a great deal into it, despite having a wide range of interests. Beyond some basic understandings I am not a scientist, & nor do I operate from a scientific reductionistic viewpoint. I do though hold a certain number of questions about the nature of certain things; which some of you may consider flawed reasoning. Your responses are helpful however to assist my understandings.
    Last edited by a moderator: Mar 21, 2008
  9. Mar 21, 2008 #8


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    Most of us who post on any kind of a regular basis are here to help; all of us are here to learn. Even Greg, who started and owns this site, occasionally has a question about something. Russ is an engineering wizard, but he'll still defer to Moonbear if it's an issue of biology. So my first suggestion is for you to start haunting the computer science section and put some of your expertise to work helping others who have problems.

    As for the sun as a nuclear explosion... I kinda fudged that for the sake of simplicity. While the process is the same as in a bomb, the dynamics are vastly different. That's something for the astronomy and astrophysics dudes to handle.

    Anyhow, welcome to PF. We try to maintain a civil community, so just try to act and react toward us the same as you would your neighbours or relatives. :smile:
  10. Mar 21, 2008 #9
    OK Danger, Thanks, I'll take a look at the computer science section.
  11. Mar 21, 2008 #10
    The atmosphere is colder if you get higher for two reasons.
    1. The suns rays mostly pass through the atmosphere and warm the surface of the earth
    2. The air pressure gets lower the higher you are. If air goes up it will expand and cool. Air that goes down will compress and heat.

    If you go up a mountain it will be cooler, but there is just as much (even slightly more) radiation from the sun.
  12. Mar 21, 2008 #11


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    This is known as hydrostatic equilibrium. The Earth is very warm at its core, somewhat warm at its surface, and the higher in altitude you go, the closer to the temperature of space you get. If this situation were reversed -- if the Earth were cold at the center and hot at the surface -- there would be a very odd pressure inversion that would not be stable. The operative concept, that astronomical bodies are hottest in their centers, applies everywhere for this reason of stability.

    The sun does not burn.

    Our eyes perceive radiation (in a small band of wavelengths) as visual stimulus. The Sun could not emit visible radiation and simultaneously appear dark, for that would be contradictory. The Sun also could not produce non-visible radiation without producing at least some visible radiation. It's effectively a giant ball of hot gas, and is therefore a 'thermal radiator' or 'blackbody.' We understand the radiation emitted by blackbodies very well, as it has been studied since the days of blacksmiths and their red-hot metal work.

    I think it's important that you stop concerning yourself with conspiracy theories. You can walk outside with a telescope and a hydrogen-alpha filter from an astronomy store and spend all day looking at the surface of the Sun -- its color, its spots, its rotation, its prominences and flares. You can also view a candle flame through your filter, and convince yourself that the light from the Sun is just as real as the light from the candle.

    If you think that the atmosphere somehow creates an illusion of light coming from the Sun, you'd be pretty hard-pressed to explain how it also creates the illusion of sunspots advancing across the face of the Sun, to disappear behind it and then re-appear a month later in the same configuration. That'd sure be one hell of an atmospheric feat.

    The reason people were gruff with you is because, despite your engineering qualifications, you have asked questions that many grade-school children can answer. That in itself is fine -- we love to teach -- but you then couched those questions in some rhetoric about conspiracies. That tends to raise the hackles of people who understand that all you need is a cheap telescope and filter to prove things to yourself with no reliance on authority.

    It it not fire, it is fusion. The Sun is mostly made of hydrogen. Deep in its core, hydrogen atoms are squeezed together into helium atoms, releasing energy in the process. This mechanism requires no air, nor any other ingredients besides hydrogen and pressure.

    Mankind has placed literally thousands of objects in orbit around the Earth. (It'd be hard to consider this a conspiracy, since it's pretty obvious that you lose your signal from your DirecTV satellite dish when the wind blows it out of alignment. Also, you can look up at night and see low-Earth orbit satellites moving with your very own eyes.) Now, satellite engineers have 50 years of experience designing and launching satellites, and have learned a great deal about them. One of the largest problems with spacecraft is, in fact, heat. One side of the satellite faces the Sun, and receives an enormous amount of solar radiation, which heats that side of the satellite up to pretty ridiculous temperatures. The other side of the spacecraft is exposed to the blackness of space, and radiates away all its heat until it is ridiculously cold. A vast amount of engineering goes into making sure the satellites can withstand these enormous temperature gradients.

    Also, the Moon provides a good example: on the sunlit side of the Moon, temperatures soar up to nearly 400K; on the dark side, temperatures go as low as 70K. (For reference, room temperature is about 300K, and water boils at about 373K.)

    Many of us here have spent our lives pursuing an understanding of the universe, and it's insulting for someone like you -- who admittedly does not even know what scientists have discovered, or by what logic they have reached their conclusions -- to claim that perhaps science is all wrong and it's a giant conspiracy instead. It's like saying you hate a symphony before the musicieans have even finished tuning up. You should consider becoming better-educated in science before attempting to dismiss it.

    Science is far from done. There are hundreds or thousands of questions without answers, some very deep. On the other hand, there are many, many things that are so well understood that they are, for all intents and purposes, accepted as truth. The fact that Sun produces light is one of them. That is not to say that such truths are accepted without evidence; in fact, they are accepted as truth only because of the enormity of the evidence.

    - Warren
    Last edited: Mar 21, 2008
  13. Mar 21, 2008 #12
    Does there an orbit exist in the (non-earth) space around the sun where we have california like weather/temperature, wearing normal clothes, and live there normally (if we carry large amount of oxygen an food?)
  14. Mar 21, 2008 #13


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    The orbit exists, but there's nothing inhabiting it.
    Please try to keep in mind that all of our climate depends upon the interaction of solar energy with an atmosphere and oceans. You would have to have an Earth-like planet in order to have a Californian lifestyle.
    Last edited: Mar 21, 2008
  15. Mar 21, 2008 #14


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    I'm not clear on the question - we currently have a California-like environment on the west coast of the US!
  16. Mar 21, 2008 #15
    yeah, but the houses are still too expensive here. I was trying find some real estate cheaper, without compromising the climate.
  17. Mar 21, 2008 #16


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    He specified 'non Earth', so that would indicate another habitable place in the solar system.
  18. Mar 21, 2008 #17


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    At $10,000 a lb just to get into low earth orbit and a powerful astronaut construction worker's union you are unlikely to do better in space.
  19. Mar 21, 2008 #18


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    Fair 'nuff, but in any case, if the earth has a California, then California-like conditions can be found at our orbital distance.
  20. Mar 21, 2008 #19
    I think the sun is a very interesting place. Nuclear fusion takes place in the interior of the sun, most of the reactions turning hydrogen nuclei into helium nuclei, but a few other elements being produced also. The gas is so dense -- the average density of the sun is greater than the density of water -- very unusual for a gas -- that it's almost a certainty that the light will be absorbed by another atom before it gets a chance to escape from the sun. Because of those odds, a typical photon is continuously absorbed and reemitted for thousands of years before it finally gets out of the sun. When the light finally reaches one of the outer layers called the photosphere, where the temperature is about 6000 kelvins, now the light has a reasonable chance to escape from the sun. Therefore the photosphere is the most direct source of the light that we see. The light as it leaves the photosphere is a continuous spectrum, meaning that all of the frequencies within a range are present. The continuous spectrum is the result of the gas being so hot and dense that it has interactions among atoms that on earth we normally associate only with solids and liquids. Then the light still has to pass through one more layer to get out of the sun. The light passes through the chromosphere. This final layer has a low density and is cooler than the photosphere, so the final change to the light occurs, the absorption of specific frequencies due to the elements that are present. What finally reaches us on earth, analyzed by what comes out of a spectroscope, is a continuous spectrum with some discrete frequencies deleted by the chromosphere, called a dark line spectrum.
  21. Mar 21, 2008 #20
    I was simply exploring a particular line of reasoning; if the Atmosphere, including the Earth's magnetic fields & van allen belts, & highly complex action of the atmosphere; had or could have more of an influence on the effect of heat & light than generally people are aware, in fact to the point that it could be possible that they do in a large part account for the transference or create heat & light through the absorption of cosmic radiation.

    As I think has been pointed out; it is the action of this radiation on solid matter which creates heat; if I have understood correctly, & also the Earth's immensely complex weather systems, interacting with Solar Radiation which gives us our environment; in the case of the Greenhouse effect; frighteningly so. I think I read this "Black Sun" theory somewhere, originally; probably on some conspiracy site, lol. Playing the Devils advocate - The only way I could be absolutely sure would be to observe the sun from within the Vacuum of Space, in which there was no Atmosphere between the observer (me) & it (the Sun).

    Well in England the way things are going I'd think many grade school children would have difficulties. We did cover this subject at school; whether I enjoyed myself too much in the 90's or I have simply forgotten what the teachers were on about; I have long held the question about how the "Heat" from the Sun reaches us, through the truly vast & cold vacuum of space. I am on my way to understanding that now however, thanks to all your posts.

    Well, I do have some understanding on many general things - including scientific, you are unaware as to my levels of understandings & as to what my understandings are in, I posted the initial question as to excuse my ignorance on that particular question. I don't follow a totally reductionistic scientific paradigm, & I don't think such a way of thinking can yield all the answers; however long we have got, but that is another matter for other more philosophical forums. It is entirely possible that we end up with large revisions; in the future, to some of our present scientific thinking.

    I'd tend to agree, & as above I don't believe that Science alone can ever supply us with all the answers. I take it you are referring to "Truth" in the Objective. Without raising questions, again largely philosophical about "the truth" & the Objective & Subjective understandings of Reality. Quantum Mechanics & Astro Physics will no doubt lead to some radical revisions on the nature of "things".
    Last edited by a moderator: Mar 21, 2008
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