Humans live in the atmosphere, and we can't see the universe, so why can we see the sun and the moon?

Because the sun is the closest star to the earth, and the moon is the satellite of the earth, the light of the sun easily passes through the atmosphere, but it will inevitably be refracted and reflected by the atmosphere. The moon is illuminated by the sun, and the light reflected by the moon can also pass through the atmosphere, and it will also be refracted and reflected. The light in the background of the universe is emitted by stars. Sirius and Alpha Centauri are the closest stars to the Earth, at least a few light years away, so their light has lost a lot in the long journey. Coupled with the refraction and reflection of the earth's atmosphere, it is covered by sunlight. Of course, it's up to you. At night, will the universe appear soon?