It is very funny. Sky is blue. But as the sun sets, the sky will be black, well let’s say there is no blue color covering, you can see the space.
Do you know why? If not, this article is for you! But it will be a very short answer:
Blue sky can be visible only daytime because the light from the sun travels in a straight line unless something gets in its way. So does the gases of the atmosphere which scatters the light in all directions. The blue light in white is scattered more because it travels in shorter, smaller waves. By this reason we see the sky to be blue when the sun shines.
Any why is the nighttime sky black? Because there is nothing to be seen. Universe is black itself. There are stars (like our Sun) which spreads their light away but light cannot be seen until it hits something (like gases of the Earth’s atmosphere). Space contains nothing in its 99.999%.
Yes, here we sit in a big, very big black space.