How many stars, satellites and constellations are there in the sky?

People with normal vision can see about 6,000-8,000 stars in a good sky background, but due to geographical constraints, people in mid-latitude areas in the northern hemisphere can only see about 3,000-4,000 stars, and they have to wait all night. The total number of galaxies currently observed in the universe exceeds 1000 billion, and each galaxy contains hundreds of billions of stars similar to the sun. There are 88 constellations in the whole sky, the largest is Ophiuchus and the smallest is Sagittarius. The most conspicuous is Orion, the northernmost is Ursa minor, and the southernmost is Antarctica.

Space is vast, but the space around the earth is crowded, and more than 790 artificial satellites from the earth gather there. According to an American organization named "Union of Scientists Concerned about Nuclear Issues", among these satellites, the number of satellites owned by the United States ranks first, with 4 13, which exceeds the sum of satellites of other countries.