Franklin Watts, 1979. Outer space is outside the earth's atmosphere. Everything is moving through space, even the sun and the Milky Way. The moon spins as it circles the earth, but at a speed that always keeps the same side facing the earth. People who study the sky and stars are called astronomers.
Gravity is the strongest force in space.
Spacecraft have to go over 17,400 miles an hour to get past gravity's pull. Howard, N. E. Standard Handbook for Telescope Making. Thomas Y. Crowell Company, 1959. In this book I learned that some time during the year 1608 Jan Lippershey's kids were playing with some of his less valuable spectacle lenses while Jan was making spectacles. His kids came running in arid told him that they put two of his lenses in front of each other and everything got bigger.