because of knowledge of mathematics, physics, astronomy that have been passed on since the past from observation, starting from the knowledge of the project style first The one we learned in high school. throw things forward its path will be a curve falling to the ground the faster you throw it goes further the radius of curvature is greater If we throw fast until the radius of curvature is the most It curves until it circles the earth and hasn't fallen to the ground, it's orbiting around the earth. Orbital speed must be very fast. However, throwing objects will have air resistance. causing the speed to drop to maintain orbital speed had to go orbit in a place where air resistance does not affect speed have an astronomer who invented the theory of orbiting the earth / around the sun ดูบอลสดฟรี
