The darkness at night is the so-called Olbers’s paradox. It has been widely discussed, and there are even books about it (e.g., Harrison E R 1987 Darkness at Night. A Riddle of the Universe). I gather that the main reason for darkness at night is that the universe is young and evolving. Surely, this needs some further explanation :-)

Dr Jose Gaite thank you for your contribution to the discussion

Thrust of the question is not obvious. However, if you are thinking of the stars and galaxies akin to many "tiny lights" put on a ceiling in a room the following might help.

In case of ceiling of the room the light of "tiny lights" is multiply scattered in the room and is also scattered by the ceiling and ceiling appears to be emitting a soft light. In the universe, the space between the stars and galaxies is almost empty and therefore scatters very little of the light of stars and galaxies.

Dr Shyam Tandon thank you for your contribution to the discussion

The colour of the sky changes as the intensity, direction of incident and reflection of sunlight on the atmosphere or sky changes with the time from morning to evening. Since at night no sunlight is available to reach the earth atmosphere therefore sky appears to show dark colour having no colour. Stars are mostly seen at night because there is no sunlight in the night. Thus, the light coming from the stars could reach us and we are able to see them. All stars, like our Sun, send out a huge amount of electromagnetic radiation, including light. However, that light spreads out with distance, making it so that only a tiny fraction reaches us. In addition, depending on the temperature of the star, the main color of light sent out by the star changes. But the sky is dark at night, both because the universe had a beginning so there aren't stars in every direction, and more importantly, because the light from super distant stars and the even more distant cosmic background radiation gets red shifted away from the visible spectrum by the expansion of the universe. The stars are not fixed, but are constantly moving. If you factor out the daily arcing motion of the stars across the sky due to the earth's rotation, you end up with a pattern of stars that seems to never change because of the scattering property of the atmosphere spread sunlight across the sky. The brightness of the sun is far more than the brightness of the far off stars. Moon and stars are present in the sky during day and night time. We don't see them easily during the day due to the bright light given out by the Sun. The celestial sphere is a conceptual tool used in spherical astronomy to specify the position of an object in the sky without consideration of its linear distance from the observer. A useful construct for describing locations of objects in the sky is the celestial sphere, which is considered to have an infinite radius. The center of the earth is the center of the celestial sphere, and the sphere's pole and equatorial plane are coincident with those of the earth. Spherical coordinates, projected on the celestial sphere, are analogous to the geographic coordinate system used on the surface of Earth. These differ in their choice of fundamental plane, which divides the celestial sphere into two equal hemispheres along a great circle. However, in order to describe the positions and movements of stars above our horizon, astronomers still use this vast imagined shell. It is called the celestial sphere. Projected onto this sphere is a grid system of reference points and lines, which are similar to maps used on Earth.

You have a good answer to your own question :-)