As a child or adult, one question that have definitely aroused in everyone's mind is "Is this universe infinite or it has some boundaries?" as a science or astronomy student this might be the first question to arouse in students mind. Coming back to the answer of this beautiful question- The observable universe is still huge but it has limits. This is because we know that the universe isn't infinitely old - we know that the big bang occured some 13.8 billion years ago. So from this we can conclude that the light has had only 13.8 billion years to travel and hence defines the limitations of universe. All we know or scientists believe is that universe is still far above from our observable distance but at some point it has limits for sure.
The color black usually signals the absence of light. But inside the solar system, space is filled with light. So what is the real reason behind the black colour or you can say darkness of the outer space. Your question, which seems simple, is actually very difficult to answer. 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 la...