Complex sentence: In astronomy, the Earth's orbit is the motion of the Earth around the Sun, at an average distance of about 150 million kilometers, every 365.256363 mean solar days (1 sidereal year).
Split into simpler sentences: In astronomy, the Earth's orbit is the motion of the Earth around the Sun, from an average distance of approximately 150 million kilometers away. A complete orbit of the earth around the sun occurs every 365.256363 mean solar days (1 sidereal year).