Question which interests a great number of children, and sometimes and their parents. Why at night darkly, and in the afternoon light? If you thought of it together with the children and do not know the correct answer, read attentively. Everything is very simple.
It is remarkable that the person since the dawn of the existence tried to offer an explanation to such phenomenon as change of day and night. It was connected with the fact that god of the sun daily came out on the fiery chariot to the sky and gave to people light, at night he left them, leaving in the power of dark deities of night and the moon. A set of legends connectof sun and the moon with romantic stories, allocating them with human qualities and presenting to roles of the unfortunate lovers doomed to eternal separation. At some people the arrival of night was personified by the big black bird closing the sky the wing, and at others the same function was performed by the night goddess shrouding the earth with a black shroud or fabric of the dress on which stars and month were sewed.
The very first and logical explanation is connected with the fact that because of continuous rotation around own axis Earth periodically turns to the Sun one, other side. The party which is to a star "face" will also be that on which at present day. Opposite it is not lit and therefore there it is dark. Though the Sun also shines very brightly, Earth closes its light own surface and does not allow it to get on a dark side.
However not everything is as simple as it seems at first sight. In 1823 the astronomer Olbers paid attention that in the Universe not one sun, therefore, light from other sun has to light both sides of our planet no matter how they are turned to the Sun of our galaxy. Long time many astronomers tried to explain Olbers's paradox, making hypotheses of protection against light by means of cosmic dust and other detaining factors. As a result scientists came to a conclusion that its remoteness from numerous light sources is the reason of lack of continuous illumination on Earth. The most part of the sun of other galaxies is at distance more than 14 billion light years and light from them simply did not manage to reach us yet. The same that are located closer, cannot create rather notable lighting.