text: Since sun from the Earth appears in a blue sky in space it is in a black background. Blue sky is the result of reflection of sunlight from very small drops of water in the atmosphere. The angle of radiation causes blue color. But sometimes when the angle changes, the color changes too. For example in dusk we have a red sky. Because of that in space there is no atmosphere (include water drops) there is no reflection and it causes a black sky. But about the brightness of sun we can say its radiation is much more dangerous than when we are on Earth. Because there is no filtering system (For example Ozone layer) and all spectrums and UVR can reach you and hurt you.