Why is the universe black

[Aki]

When we look out into the universe, why do we see black?

[Tormod]

Good question!

 

The fact that the night sky is dark has been used as proof that the universe cannot be infinite, or at least that matter cannot be distributed infinitely far away from us. If it were, then there would be suns or galaxies visible as stars in every possible direction as seen from the Earth, and the night sky would be very bright.

 

During the day, the only reason why we don't see the darkness of the universe is because the sunlight is scattered in the atmosphere.

 

But the *reason* the universe is black, is that the vacuum of empty space has no color.

[Freethinker]

Perhaps the question itself is flawed. It requires a priori acceptance of the universe being black (complete lack of energy?). The known background radiation disallows a "black" universe. It would at best have to be considered infrared.

 

We are also becoming more aware of clouds of gas being more pervasive than we ever imagined. These clouds absorb particles and thus reduce how much of them reach us. Thus stopping us from "seeing" the potentially higher level of "light" in the universe.

 

Thre is an interesting article at

 

http://science.nasa.gov/headlines/y2004/27sep_shieldsup.htm

 

It discusses how the solar wind protects us from the significantly more dense interstellar particle cloud we have been passing thru for perhaps millions of years and will continue to pass thru for perhaps another 10,000 years. Its temperature, 6000 C, is about the same as the surface temperature of the sun. Only it's low density stops us from "seeing" it as light.

[Moonchild]

Gents,the "color" of the universe is beige or khaki.

[Freethinker]

I think I am going to like you Moony!

[Aki]

Originally posted by: Tormod

Good question!

 

 

 

The fact that the night sky is dark has been used as proof that the universe cannot be infinite, or at least that matter cannot be distributed infinitely far away from us. If it were, then there would be suns or galaxies visible as stars in every possible direction as seen from the Earth, and the night sky would be very bright.

 

 

 

During the day, the only reason why we don't see the darkness of the universe is because the sunlight is scattered in the atmosphere.

 

 

 

But the *reason* the universe is black, is that the vacuum of empty space has no color.

 

 

You say the universe the infinite, so am I correct if I say the shape of the universe could be like a ball?

 

And then about the "no colour" thing, isn't black be a colour?

[Tormod]

Originally posted by: Aki

You say the universe the infinite, so am I correct if I say the shape of the universe could be like a ball?

 

No, I say the opposite: the darkness of the night sky is used as proof for a *finite* universe!

 

The shape of the universe is an interesting discussion but it is off topic here. Maybe a new thread?

 

And then about the "no colour" thing, isn't black be a colour?

 

Technically, black is the absence of color while white is the sum of all colors.

[Tormod]

Originally posted by: Moonchild

Gents,the "color" of the universe is beige or khaki.

 

I'd say it's blue on Mondays but rather more diverse on Saturdays.

 

Seriously, didn't someone suggest it was green a while back?

 

Anyway, Moonie's answer is supported by this article from space.com:

 

Color Corrected: Johns Hopkins Researchers Say Universe Much Blander Than Before

http://www.space.com/scienceastronomy/universe_color_020308.html

[Aki]

Originally posted by: Tormod

Originally posted by: Aki

 

You say the universe the infinite, so am I correct if I say the shape of the universe could be like a ball?

 

 

 

No, I say the opposite: the darkness of the night sky is used as proof for a *finite* universe!

 

 

.

 

oops, I typed the wrong thing, yes I meant *infinite in the first place.

[Aki]

Originally posted by: Tormod

Originally posted by: Aki

 

And then about the "no colour" thing, isn't black be a colour?

 

 

 

Technically, black is the absence of color while white is the sum of all colors.

 

Ah, I always thought black is the sum of all colours because when you mix all the colours together, you get up with black.

[Tormod]

Originally posted by: Aki

Ah, I always thought black is the sum of all colours because when you mix all the colours together, you get up with black.

 

Yes...that's beacuse when you mix colors on a sheet of paper you add color absorption to it so in effect you end up with a black color.

 

Newton used prisms to break down the color of sunlight and what he found was that sunlight could be broken down into any color (ie, the prisms showed rainbows, for example).

[Freethinker]

Yes in colors/ physics/ there is additive and subtractive. Paint or crayons absorb or reflect light and work as subtractive. Thus when you combine all colors you get black. The primaries are considered Red, Blue and Yellow

 

But sources that generate light work additive. When you mix all colors you get white. The primaries are Red, Blue and Green.

 

The CRT's we use for our computers are additive. If you look really close you will see that there are only red, blue and green dots that combine in our eyes to produce the shades and intensities we see.

 

LCD's use a "white light" source behind and color filters that allow varied light levels through.

[lindagarrette]

Here's a more colorful article . The universe seems to be a pinkish ivory.

http://www.pha.jhu.edu/~kgb/cosspec/

[Uncle Martin]

Originally posted by: Freethinker

The CRT's we use for our computers are additive. If you look really close you will see that there are only red, blue and green dots that combine in our eyes to produce the shades and intensities we see.

Could you please explain the color yellow, considering your previous explanation. What combination of red, blue or green gives us the yellow I see in your avitar?

[Aki]

Originally posted by: Uncle Martin

Originally posted by: Freethinker

 

The CRT's we use for our computers are additive. If you look really close you will see that there are only red, blue and green dots that combine in our eyes to produce the shades and intensities we see.

 

Could you please explain the color yellow, considering your previous explanation. What combination of red, blue or green gives us the yellow I see in your avitar?

 

ooooh, that sounds like a good question I'd like to know the answer to that.

[Freethinker]

Originally posted by: Uncle Martin

Could you please explain the color yellow, considering your previous explanation. What combination of red, blue or green gives us the yellow I see in your avitar?

Yellow is the color of a banana. :-)

 

OK, to answer your question:

 

"Additive color mixing: adding red to green yields yellow"

 

http://en.wikipedia.org/wiki/RGB

 

You will find a nice explanation at this site. Including a color mix pallet.

 

There are also lots of aps that allow you to see hex and RGB levels as you mix colors visually. One particularly nice one is at:

 

http://www.jgiesen.de/ColorTheory/RGBColorApplet/rgbcolorapplet.html

 

It has RGB sliders to adjust the relative value of each, along with R, G and B circles that can be moved to overlap and show mixture results.

[Freethinker]

Originally posted by: Freethinker

Yellow is the color of a banana. :-)

Ever seen a blue banana?

 

It was very disappointing to not find many sites that discuss this moment in history. It was a well known story in Broadcast TV circles.

 

Back in the day (as they say these days), when Color TV was first being developed, technology was still very basic. No automatic adjustments. In fact adjustments were not only completely manual, but unstable and lacking standards. Color video cameras consisted of 4 pickup tubes, one each for R,G,B and "luminance" (B&W). Adjustments to the 4 outputs had to be made manually to get the correct colors out of the camera. But no standards or test charts where in place yet. So they would use what ever was around. A bowl of artificial fruit was popular as it contained lots of colors which could be known without direct visual comparison between the TV pict and the original scene as adjustments were made in a room removed from the studio. Plus the cameras required lots of light and took a long time for the cameras to stablize and be adjusted. So people sitting didn't work (to get flesh tones) and real fruit would spoil.

 

Some wiseguy decided to play a trick. He painted the banana blue. All the techs in the control room, since they could not see the fruit bowl directly, assumed the banana was yellow. They worked for hours trying to adjust the camera for a yellow banana. As they were going live soon, they were all panicing. Then someone went to the studio to see what the problem was and saw the blue banana.