Is Space black, or is it an illusion?

I was wondering whilst reading my other thread, When i look into the dark sky at night, it appears black. And in movies and games, i kno not a good source, when there in space, they can always see, even though there isnt any source of light. Would it be like that? Or would you not be able to see in front of you if there wasnt any light?

Not sure about that, but I know they've pointed out, that if you were to look at the whole universe, it'd be Beige.

Space is huge, with vast emptyness . However - there are a lot of stars. So i think that there could be few places (like inside nebules/gas clouds) where it would be dark. However mostly it is dotted with stars. Not good enough to read a book of course. But still not total black. We see only few stars due to sun/moon illumination and atmospheric issues.
So take a trip outside the city to the wilderness in the night with not full moon - and you will see how it looks. Plus/minus.

[edit on 11-5-2009 by ZeroKnowledge]

found this


starchild.gsfc.nasa.gov...

Why is space black?

Answer: Your question, which seems simple, is actually very difficult to answer! It is a question that many scientists pondered for many centuries - including Johannes Kepler, Edmond Halley , and German physician-astronomer Wilhelm Olbers. There are two things to think about here. Let's take the easy one first and ask "why is the daytime sky blue here on Earth?" That is a question we can answer. The daytime sky is blue because light from the nearby Sun hits molecules in the Earth's atmosphere and scatters off in all directions. The blue color of the sky is a result of this scattering process. At night, when that part of Earth is facing away from the Sun, space looks black because there is no nearby bright source of light, like the Sun, to be scattered. If you were on the Moon, which has no atmosphere, the sky would be black both night and day. You can see this in photographs taken during the Apollo Moon landings. So, now on to the harder part - if the universe is full of stars, why doesn't the light from all of them add up to make the whole sky bright all the time? It turns out that if the universe was infinitely large and infinitely old, then we would expect the night sky to be bright from the light of all those stars. Every direction you looked in space you would be looking at a star. Yet we know from experience that space is black! This paradox is known as Olbers' Paradox. It is a paradox because of the apparent contradiction between our expectation that the night sky be bright and our experience that it is black. Many different explanations have been put forward to resolve Olbers' Paradox. The best solution at present is that the universe is not infinitely old; it is somewhere around 15 billion years old. That means we can only see objects as far away as the distance light can travel in 15 billion years. The light from stars farther away than that has not yet had time to reach us and so can't contribute to making the sky bright. Another reason that the sky may not be bright with the visible light of all the stars is because when a source of light is moving away from you, the wavelength of that light is made longer (which for light means more red.) This means that the light from stars that are moving away from us will become shifted towards red, and may shift so far that it is no longer visible at all. (Note: You hear the same effect when an ambulance passes you, and the pitch of the siren gets lower as the ambulance travels away from you; this effect is called the Doppler Effect).

imagine.gsfc.nasa.gov...

Hello, I am 4 years old and I would like to know why space is black. Thank you for taking the time to answer me. (My auntie is typing this for me)

The Answer This is a very good question!

Do you know why the sky is bright and blue during the day? It's because the Sun is shining on the air, so the air becomes bright. The Sun is shining in space too, but there is no air for the light to bounce off of in space. That's why space is black.

Best wishes, Koji Mukai for Imagine the Universe!

which is kinda funny cus they are from the same place almost...


[edit on 5/11/2009 by mahtoosacks]

I was always under the impression that space looked black because it's a vaccuum, and therefore light doesnt show.

Its not actually black, its void of color and light.

Am I wrong it that.

In the tiny are of space we have already explored, an astronaut can see everything around him/her as they are close enough to the sun to have a constant light source. In fact the sunlight experienced in space is an order of magnitude stronger than that which we experience on Earth. Because space is a vacuum none of it is reflected by by the atmosphere. To put this in perspective have you ever been out in the countryside on a very foggy night? We can usually still see by the sunlight reflected from the surface of the moon but in the fog (basicly just low cloud) we can see nothing at all. If one were to travel to an area of space containing few or no stars such as the galactic void then an external lightsource would be necessary. Equally, as the previous post suggests, a nebula may act as some kind of 'space fog'.

Anyway, rambling post over and in answer to your question not all of space is black, just most of it.

keep rockin'

Digdeep

edit, apalling spelling of two letter words!


[edit on 11-5-2009 by digdeep]

I think of it this way. A light source must be able to "hit" something or else it's a single point of light and doesn't "brighten" anything.

Think of it like this. A lightbulb dangling from a cord in the middle of a very wide, very tall warehouse. The only thing you can see is the the bulb itself plus a little of the bulb holder and the cord to connect the electricity. However, if you move it closer to the floor, it then illuminates the floor. It gives the sense of being brighter because it's shining back on something.

Since empty space, in the most general sense, is without a substance to illuminate, the light of distant objects appears singular.

Black is simply the absence of light, but we know there is light all over the universe in every star and galaxy. Simply put, in order for us to see light it has to do one of two things.

1. It comes in direct contact with your retina and you see the light coming from the source.

2. Light has to reflect off of something (which inherently absorbs certain frequencies of light hence color) and then bounce back and hit us in the eye.

We can also see a reflective effect from particles (aka the sky is blue). Explained - The sunlight penetrates the atmosphere and bounces off of the ocean which is then reflected by the particles in the atmosphere.

Hope this answered your question.

Originally posted by WickettheRabbit
I think of it this way. A light source must be able to "hit" something or else it's a single point of light and doesn't "brighten" anything.

Think of it like this. A lightbulb dangling from a cord in the middle of a very wide, very tall warehouse. The only thing you can see is the the bulb itself plus a little of the bulb holder and the cord to connect the electricity. However, if you move it closer to the floor, it then illuminates the floor. It gives the sense of being brighter because it's shining back on something.

Since empty space, in the most general sense, is without a substance to illuminate, the light of distant objects appears singular.

Um, that's mostly wrong. A star emits light. That light goes out in all directions. When it hits something that object is lit up. A light bulb doesn't "illuminate" the floor because it's not very strong and the light diffuses rapidly. As proximity grows the amount of light hitting an object increases.

reply to post by Gawdzilla


I don't see in any way how what you said differs from what I said.

I really don't.

The light from a star or a lightbulb must illuminate something to appear as something other than a single point of light.

What did I miss?

Technically it's not black... technically you can still see the light from all the other systems way out in the distance.

However, the ambient light around you and the light from close bodies in space are so intrusively bright compared to the depths of space, that the depths of space appear as black relative to everything else.

If you took away all of the nearby light, you'd be able to see much further... once your eyes adjusted of course.



Same reason you can see more stars in the country than in the city... yet both skies are black.
Its all relative.


Here's another way of thinking of it.
If I turn on an almost dead flash light in a black room with the lights off, I can see it shine off the walls.
If I turn on the lights... I can't see the flash lights light any more... it appears as though it's not emanating any light at all... but the walls remain black.

The ambient light is just too bright compared to the dimmer light from the flash light to be able to see the flash light.

Well I think it was explained best earlier, but I will add my take on it.

Why is space black?

Space is appears black more than anything because it is such a large "space" compared to the amount of illumination sources (ie; stars) that the overall size overcomes the overall number of stars available for illumination. That is the most fundamental reason why it is black, after that you can go into the age of the Universe and the speed of light. Black is the absence of illumination. Why? Because that is just how our physical system of reality is set up. Maybe in another universe (level 4 for example) the laws of physics are different and white is the absence of light or so on.

A perfect example would be a "Blackbody", a Blackbody is a body that absorbs all the EM radiation (Light, IR, UV, etc) that falls on it, thus reflecting nothing back in the form of any form of observable EM radiation (like visual light). A perfect blackbody (only theoretical) would absorb ALL EM radiation that falls on it, and thus be totally black, hence the name "Blackbody". So it is true that black (darkness if you must call it that) is the absence of light, or any EM radiation for that matter.

Here are some graphs depicting the Blackbody curve and luminosity courtesy of wikipedia.org

Blackbody Curve...




Blackbody chromaticity chart...



On an unrelated but relevant note; It is important to understand that the color of an object illuminated depends entirely on its' temperature.

Another Explanation to Why The Natural Color of Space is Black

I think another question that could arise from this in a Theoretical Physics and Cosmology standpoint would be are we inside of a perfect Blackbody, and could this related to one of M- Theory's postulate that a membrane occupies the whole of our spacetime?



The video is a multi-part series explaining M-Theory.

Helpful Sources

en.wikipedia.org...

hyperphysics.phy-astr.gsu.edu...

en.wikipedia.org...

en.wikipedia.org...

en.wikipedia.org...

[edit on 5/13/2009 by jkrog08]

Here's the simplest explanation:

The "color" black, with respect to the visible light spectrum, is the absence of all color. Color only occurs when light reflects off the surface of matter. Since empty space is a vacuum and contains no discernible matter, there is nothing for the light to reflect off of. That's why it looks black, because there are no light rays being reflected back into your eyes.

[edit on 13-5-2009 by paradigm619]

Originally posted by AntiConspiratorAnd in movies and games, i kno not a good source, when there in space, they can always see, even though there isnt any source of light.

They can see from ambient light sources, Sun/Star, Earthshine, moonshine, nebula shine, etc...

If you are in very deep space, it will be dark but not totally..

I don't have experience going in deep space yet, but I do have experience going out at sea all lights off in a motorboat, in a remote area, far away from civilization(no visible artificial lights all points of the horizon) on moonless, but otherwise, very clear night sky at midnight.... One of the darkest situation you can be in...

But it wasn't totally dark, you can see the ocean waves, you can see where you're heading, you can see the boat, the person's face next to you, you can see the land far away. Light coming from the Milky Way Galaxy and all the other stars is just bright enough to show where you're heading.. I believe in outer space, it will even be brighter, so unless, you're in the middle of intergalactic space, you shouldn't be worried of near total darkness in space.

[edit on 13-5-2009 by ahnggk]

[edit on 13-5-2009 by ahnggk]

Originally posted by cautiouslypessimistic
I was always under the impression that space looked black because it's a vaccuum, and therefore light doesnt show.

Its not actually black, its void of color and light.

Am I wrong it that.

Then how come light from the moon can reach us and make things brighter on earth?

Originally posted by Nventual
Then how come light from the moon can reach us and make things brighter on earth?

You are correct because outer space isn't opaque....

BUT an exception is the galactic plane, it's largely opaque(making it look black without much light) due to interstellar gas and dust, that's why we can't see the 'Galactic Center', if we can see it, it's a sight to behold!

But empty space isn't completely black.. It fluctuates with virtual photons and particles. We should be thankful we can't see it or we'll get blinded in the dark!

[edit on 14-5-2009 by ahnggk]

Originally posted by cautiouslypessimistic
I was always under the impression that space looked black because it's a vaccuum, and therefore light doesnt show.

Its not actually black, its void of color and light.

Am I wrong it that.

But space is not void of light.

allways a star or something burning.

and lets just say space is a vacuum to vacuum something something has to be sucking pretty hard lol

and last time i looked there is no wall's or solid object that hold's us in this space.
There fore light could possible be a outside transference so to speak.

lets say i make a crude vacuum of a pop can and 2 hose's ...
what will happen?
the can will crush.

the universe is expanding.
A vacuum could not and will make our AKA space bigger.

so is space a vacuum?

void of oxygen is spot's yes.

but a vacuum i can't grasp the idea..
i know science says it is.

to the op question of blackness.

When you look outside what do you see when you look up?
star's.

So even if you was floating in space..lost adrift...you would see star's.
there fore always some light would hit your eye's.