10. Mariner 2 was America’s first successful interplanetary spacecraft that successfully passed by Venus. At 19:59:28 on December 14th, 1962, Mariner 2 arrived at the closest distance to Venus.
11. Ganymede is the largest moon in the solar system, it was observed by the astronomer Galileo Galilei in 1610.
12. Saturn is a gas planet, consists of hydrogen and helium. It has a small rocky core surrounded by hydrogen and helium. Besides there is no any other rock.
13. The Venus takes longer to revolve on its axis than revolve round the sun, the former needs 243 days, the latter needs 225 days, it is the slowest planet to revolve on its axis in the Solar System. That’s so called “one day is longer than one year.”
14. Halley’s Comet is the most famous short-period comet, it visits the Earth once every 76 years. Britain astronomer Edmond Halley had predicted that this comet would return again in 1758, and his prophecy was confirmed sixteen years after Halley’s death, then this comet was named Halley’s Comet in memory of him.
15. Diving training is one part of astronaut training, because the weightlessness which diving brings is very similar to space walk.
16. Saturn is one of the most beautiful planets in the solar system, the most prominent characteristic is that it has beautiful Saturn’s rings made up of crushed ice, rocks, dust and particles.
17. The footprint left by Neil Armstrong on the Moon 44 years ago still remains today. There is no atmosphere, water and other substances, so that footprint will not be destroyed, also known as the permanent footprint on the moon.
18. In 2004, a Diamond Star called BPM 37093 was discovered by astronomers, the distance between it and the Earth is about 50 light-years, it is a complete diamond, weighs up to 10 billion trillion trillion carats.