Flexi Says: The Sun is the center of the solar system, which includes all of the planets and other bodies that orbit it. It is by far the largest part of the solar system. Added together, all of the planets make up just 0.2 percent of the solar system's mass. The Sun makes up the remaining 99.8 percent of all the mass in the solar system and is roughly 54 times the radius of the Earth that approximately about a million Earths could fit in the sun. The sun mass is approximately 2 x 10^30 kilograms.