In this chapter, basic properties and parameters of the solar system are discussed. The Sun is the gravitational centre around which the planets orbit in elliptical orbits. It is a rotating plasma sphere in which nuclear fusion produces the radiation we perceive as sunlight. Its rotation and turbulence drive a dynamo that generates the Sun’s variable magnetic field. Its magnetism ultimately causes the heating of the corona and acceleration of the solar wind, which forms a huge plasma bubble in the interstellar medium. This heliosphere extends to about 100 times the distance of the Earth from the Sun. Eruptions on the Sun and the variable solar wind are responsible for space weather, which has an impact on humanity’s technical civilization and space travel, especially in near-Earth space. An essay gives reasons for doing space plasma physics.