Why is outer-space black?

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Outer-space looks black for the same reason that your bedroom would look black if you turned off all the lights. It's because it's dark! Every time we see a color, it's because we see light coming from something or being reflected off of something. Blackness is what we see when there isn't any light shining or reflecting at all!

There are a lot of stars in the Universe, just like our Sun. There are lots of planets, moons, comets and asteroids too, but there is a lot more empty space. It's a huge amount of space to think about. Even a huge planet like Jupiter that has lots of colors only appears in the sky as a small spot of light. Because there is so much emptiness, the amount of light is very small in comparison, so the Universe is dark and looks black.


by   (whyzz writer)
  • Exploration


    Light Limits



    Have you ever shined a flashlight outside at night? It's helpful to see things that aren't too far away. Maybe you dropped something and need to find it. A flashlight is great for that.  But how well does a flashlight work over a long distance?


    Try going outside when it's dark, making sure you have a grown-up you trust there with you. Take a flashlight with you and shine it at the ground. How brightly is the ground lit up? 
    Next, shine the flashlight at the farthest thing you can see. Don't shine it into people's windows though because you could scare them. How brightly is this object lit up? Is it more or less than when you shined the flashlight at the ground?
    What do you think happens to light as it travels very far? There are a lot more stars in the Universe than we can see. Some are just too far away for us to notice their light. That's part of the reason the Universe looks so dark. 
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