Why does space appear black?

[junglelord]

I'm just a bit curious here.

There is an interesting chart of the Electromagnetic Spectrum here. As is familiar, the spectrum of visible light falls within a pretty narrow area of what is know so far of this spectrum.

It seems to me that any frequencies to either side of the spectrum of visible light would naturally appear 'black'. Simply because they don't fall within the required range of visible light.

I remember reading a book back in 1974, how the bionic man was made a symbiosis with a shuttle. He was able to see the other spectrums via the shuttle's detectors....and the universe was full of colour.

[klypp]

You're right on, Solar!
I've been told that if you want to watch the really bright spectrum at night, all you have to do is turn on your TV set and unplug the antenna!
Enjoy!

[webolife]

Part of the issue of space blackness is the misconception of wavefronts of light spreading across your line of vision.
A "lightwave" from a star for example should be virtually uniform and dimly white if at all visible, because the wave front has so spread out as to make distinguishing of the star-point impossible. In fact the whole sky should appear this way at all times. Let's go further... everything we look at everywhere should be just one great blur of wavefronts, if light behaves as classical/relativity theory implies.
That this doesn't happen anywhere we look, but rather images of actual objects appear, is the biggest and simplest reason to conclude that light is not waving after all. The spherical wave model for EM radiation simply does not work. Further consideration, and some simple experiments, can show that light connects our eye, radio antenna, or other photodetector, to the source by means of lines, lines of sight, or actually rays. Simple geometric ray diagrams demonstrate the true nature of light, that it is neither particulate nor wavish, but vectors of force, ie pressure, directed straight toward the center of the field, the light source/sink. Hence "perfect" images of the source/field appear. When using a pinhole, slit (like a spectroscope or slit apparatus) or lens, these vectors are spacially ordered such that the spectrum of light seen wrt the lightsource is an image of the light pressure field gradient. Un-ordered, your eye does not connect with the vectors, hence, black. No (material) medium required by this explanation, and no c-rate for light transmission across space.

[MGmirkin]

hello BlueCrab,

Why does space appear black?

As opposed to being filled with the glow of endless stars and galaxies?
Are you refering to [url2=http://en.wikipedia.org/wiki/Olbers'_paradox]Olbers Paradox[/url2]?

If the universe is assumed to contain an infinite number of uniformly distributed luminous stars, then:

1. The collective brightness received from a set of stars at a given distance is independent of that distance;
2. Every line of sight should terminate eventually on the surface of a star;
3. Every point in the sky should be as bright as the surface of a star.

Don Scott has written on this subject, explaining it as simply a result of the limitations of the human eye, which cannot perceive light beyond a certain magnitude.

It may also help to remember that the human eye is different from
photographic film or a CCD chip. It does not integrate over time. The
longer we expose a photographic plate to starlight the brighter the image
becomes. (There is a limit even to this process in film due to what is
called reciprocity failure.) But, humans can stare at the night sky all
night long and not see anything they didn't see after the first few minutes.
Things don't get brighter for us the longer we look at them. So
theoretically the longer we expose our CCD camera chip, the brighter the
image (deeper into space we can see). This is not true for the human eye.
We can see the 8400 or so stars that we can see, and all the zillions of
others might as well not be there AT ALL as far as our humble naked human
eyes are concerned.

Olber's Paradox is not a paradox at all if you look at it correctly. It is
yet another example of theoretical mathematics applied incorrectly to a real
world phenomenon. Or a mathematician might say, "They got the upper limit
on the integral wrong."

Don Scott
http://www.kronia.com/thoth/ThVIII02.txt

Nick

Wow, you mean I might be able to add something to this (assuming it hasn't already been brought up)? Cool! At least 3 other considerations:

1) The human eye cannot see the entire spectrum.
2) The Earth's atmosphere screen out some portions of the spectrum, so even if we could see it, we wouldn't necessarily unless we were outside the atmosphere, but then we'd be dead.
3) Intensity laws for appx point sources.

Part 1: The human eye sees only a very small portion of the EM spectrum. Any part we can't perceive, appears black. Black is null, black is the "lack" of light [that we can perceive].

It's interesting to watch movies recorded with a FLIR / infrared camera. It picks up a different portion of the spectrum than what we are able to see and converts it into "false colors" colors (in the "visible" part of the spectrum) we can comprehend.

I'm sure that devices can probably be made to do the same for x-rays, microwaves, etc. Would be interesting to take video of various things like lightning or tornadoes in different wavelengths and then overlay them to see what all we're missing with our limited eyesight.

Part 2: The ionosphere absorbs, filters, or reflects out some portions of the EM spectrum. So, even if we could see those portions, the photons might not ever reach us to be seen! That's one reason we like putting satellites into orbit. They get outside most of the atmosphere and are able to more clearly see things that are obscured or invisible from inside the atmosphere, in addition to being able to see parts of the spectrum not visible in "visible" light.

Part 3: What was part 3? *Scrolls up*

Ohh, right, intensity laws...

Might want to look up Irradiance or Luminous intensity...

From the Irradiance article:

If a point source radiates light uniformly in all directions and there is no absorption, then the irradiance drops off in proportion to the distance from the object squared, since the total power is constant and it is spread over an area that increases with the square of the distance from the source.

In other words. stars are a long, long, long way away. So, whatever emissions they make per second or per hour generally spread out over vast distances. They may spread out such that they drop below the threshold at which we can perceive them. Though, if on were to assume that thee are stars in every direction then one might ask why there isn't a "fog" of light as various waves from different point sources overlap or intersect. But, Don Scott's answer seems to answer that. There *IS* a fog out there, but it's below our perception threshold, or outside our "visible" part of the spectrum. However, cameras can accumulate light from the "fog" or point sources below our perception threshold. That's why satellites and radio telescopes may use long exposures to ferret out more and more faint signals.

And that's not even getting into the issue of light being blocked by intervening dust, absorbed by the interstellar medium, or being absorbed in the visible part of the spectrum and re-emitted in non-visible parts of the spectrum (IR, UV, x-ray, microwave, radio wave, etc.).

Cheers,
~Michael Gmirkin

[webolife]

But Don Scott's explanation does not explain why we see images of objects.
Optical diagrams using straight lines to model light behavior explain this fully.
Light is lines. That is to say, light is rays. Vectors. Cones of pressure directed toward the source,
not emitted from it, as particles or waves, so as to spread out and blur the energy.
I agree with the statements quoted from Don Scott, and Olber's paradox is not a problem for me,
but only ray diagrams can explain imaging, not any kind of particle/wave explanation.

[Solar]

... only ray diagrams can explain imaging, not any kind of particle/wave explanation.

'Refraction' explains imaging. As in light refracted through a medium.

"Refraction is responsible for image formation by lenses and the eye."

It's a curiosity to me (in general) that when speaking of light from distant stars; the plasma medium(s) through which it must 'pass' - if in fact light is 'emitted' and 'travels' - seems not to be taken into consideration as having a 'refractive index'.

Ray diagrams are a 'visualization tool' of refraction, and can be used for "visualizing the image location and size" - which is why it's called a "diagram". Refraction is the event it approximates.

[klypp]

MgMirkin wrote that "The Earth's atmosphere screen out some portions of the spectrum".
Here's a fascinating illustration from NASA:



At sea level visible light is about the only waves getting through!

Grote Reber was the first one to look at the sky at the radio spectrum. Here is what he saw:

Some years ago, a very large radio telescope was designed and built by one of us (G. R.) in order to detect very long radio waves. The instrument was designed to observe at a wavelength of 144 m. It consists of 192 dipoles, mounted in an array 3520 ft. (1.07 km) in diameter covering 223 acres (90 hectares). This makes it one of the world's largest telescopes. During the minimum solar activity in the mid-1960, the southern sky had been mapped at that wavelength. It was found [4], [13], [19] that the appearance of the sky is the inverse of that at shorter wavelengths (i.e. galaxies appear dark on a bright intergalactic background).
This shows that at such a long wavelength, it is possible to detect radiation in the direction of intergalactic space. Furthermore, at that wavelength, the galaxies are no longer transparent and appear as shadows on the illuminated cosmic background. This experiment provides completely new information on intergalactic space.
From these results it is calculated that the density of radiation observed [4], [13], [19] at that wavelength of 144 m corresponds to a plasma temperature of 3.4 ´106 K. Since radiation is observed for the first time from a direction in space where there is no resolved galaxy (intergalactic direction), the radio signal detected had to travel across an important part of the universe before reaching us. If one assumes that the radiation is produced by the hot intergalactic plasma, this would require an average plasma density of 0.01 atom per cm3 [4], [13], [19]. Another assumption is that the radiation is produced by plasma coming from many very remote unresolved galaxies. More data are required at these long wavelengths in order to know the origin of that radiation. More knowledge on the amount of intergalactic matter would be useful to determine the origin of that radiation.

A bright sky with dark stars!

And intergalactic plasma... I love it!

[junglelord]

Thats what I said about the novel I read in 1974 or so with the Bionic Man and a symbiosis with a Shuttle. The universe is alive with colour. If one could be hooked into a series of dectors and see with the sight of the dectors, one would see a universe of colour, not a black sky.

[beanoldboy]

Maybe it appears black because we live in a black hole !! We don't circle the sun but we follow it in a spiral like motion as it travels trough our galactic spiral heading inward as we our in our in our solar system. Maybe we have a black hole in our solar system, just in a different scale- Hurricanes, water going down drains, galactic spirals are all similar phenomena.
Remember, we thought the world was flat once

[junglelord]

Maybe it appears black because we live in a black hole !!

I got a quote for that idea...

A pleasant faced man steps up to greet you
He smiles and says hes pleased to meet you
Beneath his hat the strangeness lies
Take it off, hes got three eyes
Truth is false and logic lost
Now the fourth dimension is crossed

You have entered the twilight zone
Beyond this world strange things are known
Use the key, unlock the door
See what your fate might have in store
Come explore your dreams creation
Enter this world of imagination

Wake up lost in an empty town
Wondering why no one else is around
Look up to see a giant boy
Youve just become his brand new toy
No escape, no place to hide
Here where time and space collide

Neil Peart/2112/Twilight Zone
http://www.youtube.com/watch?v=6-gabo4vIXA

LIght would not flow the way it does if we lived in a black hole by the very nature of black holes....think about it.

I often wondered how could ANYONE think the world was flat, did they not see the moon?


PS nice to meet you....

[webolife]

Back to you, Solar...
Refraction is simply the property of the change of direction of a light ray encountering a difference of media density. It can be shown that refraction is a "conservation of area" phenomenon, an the holographic principle. That waves can refract is a consequence of conservation of energy, but refraction of light via a lens simply redirects the straight lines of sight through a focal point, producing the image. An image is produced (sans the mechanism of refraction) using any type of pinhole device, camera obscura, or slit apparatus, by a similar ordering of the light rays through a focus... Newton attempted to relate this to his optics conception of particality for light. But it can be shown handily with a 2-slit device that "photons" are not particles, at least in the indivisible sense of the term... the same device can be used to neatly demolish the Youngian conclusion that light waves, and most certainly it does not interfere!! Neither Isaac Newton's light particles, nor his contemporary Christiann Huygens' and later Thomas Young's light waves, nor the misconception of particle-wave duality truly conform to the actual observations they made of light (and they knew it!), but another of their contemporaries, the brilliant Rene Descartes had what I believe was a more correct understanding: Light is Pressure!! What Descartes missed, and what I add, is that the direction of pressure is toward the source, rather than emitting from it. Newton and Huygens both understood the impossibility of modeling pressure as a spherical emission from a source, so their ideas won the recognition of the science community from that time on. Had any of them considered the option that light is not emitted from but rather directed toward the light source, as a sink, a lot of the current confusion, and uncertainty, surrounding the functioning of light may have been resolved. Ray diagrams show imaging because they dilineate rays of light, ie.vectors, which describe what I assert is the true nature of light: it is a force, ie pressure, and a function of the unified field of the universe.
No wavish explanation, especially when you try to take into account the possible refractivity of a transmission medium, can satisfy the reality that we see discrete points of starlight in the sky at vast distances. No media is needed in this explanation, so no refractive index is indicated. Olber's paradox does not apply, and the highest magnifying telescopic images still show non-sources of light as black. Simplest of all, a light vector "tugging" on our retina, ie directed toward the source/sink, appears bright, those directed toward our retina are black. Take a good look in the mirror at yourself... the blackest object in the universe is that little circular pupil right there in the center of your virtual eye. What we call the visible spectrum is the image of the light pressure field about the central line of sight. It is not a distorted "diffraction" of otherwise parallel/concentric wavefronts. This is easily seen with any slit device or prism. The image of the object still appears right there where you would expect it, and the ordered vectors of the surrounding pressure field appear to the sides. A "diffraction grating", such as the eyepiece of a spectroscope, is simply used to reflect the imaged vectors back to your eye or recording device. This also explains in the simplest possible way why a light "signal" cannot be reflected back on the same line it is transmitted... vector cancellation... black.
IMHO.

[webolife]

Another point regarding the so-called "visible spectrum"...
You must understand that all light is transparent from radio to gamma, and is imageable only by the correctly resonant absorbers/detectors... our retinas are good detectors of magenta through indigo, via red, yellow, green and blue photoreceptors.
Flying insects seem capable of detecting the higher range UV rays, while other animals are no so great at detecting the colors... so what we call the visible spectrum is not so much due to the nature of the light as to the nature of the detector.
Note my use of "resonant" and my "higher range" comment in no way imply a concession to light wavishness or indicate for me anything about light wavelength or frequency, although I'll not be the last to suggest that detection devices, made as they are of compounds and elements, own a wide variation of resonant traits (my way of avoiding the word "spin"... oops), responding to the spectral pressure gradient in unique ways as dyes, filters, reflectors, etc. As I tell my students: All light is invisible. If our eyes were radio antennae, we might "see" T.V. on the screen of our retina! Therefore without the proper detector, everything would be "black"!

[Solar]

... the brilliant Rene Descartes had what I believe was a more correct understanding: Light is Pressure!! What Descartes missed, and what I add, is that the direction of pressure is toward the source, rather than emitting from it.
...light is not emitted from but rather directed toward the light source, as a sink, a lot of the current confusion, and uncertainty, surrounding the functioning of light may have been resolved. Ray diagrams show imaging because they dilineate rays of light, ie.vectors, which describe what I assert is the true nature of light: it is a force, ie pressure, and a function of the unified field of the universe.

I guess I'm not understanding this relationship my friend.

If I look towards a light source, the Sun for example, and the light pressure (aka radiation pressure) is directed towards the source as a "sink"; then why don't my pupils reside in the back of my eyes ("detection devices") to more readily receive and phase shift the pressure impulses?

It seems as if were this the case the planets would cast shadows on the face of the Sun, and to face a light source would cast a shadow in the direction of said source; not away from it.

[webolife]

Solar,
I don't understand what you are saying...
When the electrical field of the atom collapses, ie drops to a lower energy state, as is happening ubiquitously on surfaces everywhere, but take the Sun for example, that "collapse" of the field at which my eye is toward the periphery, causes my retina to experience a "tug", actually a "push from behind" in recognition of the unified field as centropic pressure, ie directed toward the source. That tug registers on my retina's photoreceptors as an "impulse", which is transmitted electrochemically to my occipital lobe and interpreted as light. Where you get the pupil as being a photoreceptor I don't understand. The pupil, pinhole, or slit, simply orders the holographic pressure field into an image, and in the case of the narrow pinhole or slit, a gradient which patterns as a spectrum. Areas of explosion on the solar surface, solar flares and prominences, etc. occur at sunspot regions... in my model these areas of outward movement produce a transient weakening of the centropic pressure, hence the darkening of the surface, also where the ejecta return to the surface surrounding the sunspot appears bright, as this relative motion reinforces the centropic vectors of the solar field. The optics of this model are identical to classical optics, with the key exception that the vectors are reversed, light is not emitted, but rather centrally directed toward the source. If I understand anything about your objection, it seems to be that you are still trying to imagine light as stuff moving through space, which I don't. I honestly don't get at all what you mean by planets casting shadows on the sun........

[junglelord]

As the local medical professional and anatomy expert and one who is very up to speed on holographic consciousness, I cannot accept your model of the eye and sight via this pull.

That is all backwards.


You know I respect you and your thoughts, but I have to call a spade a spade.


I think its not impossible to have a sink at the source along with a push from the source. That would satisfy both of us then.