Earth is an ordinary small lump of gas and dust in the milky way galaxy, one of 50 billion. About 150 million km from the sun (8. 33 light minutes away: perihelion is the closet point @ january 3rd, aphelion is the furthest point @ july 4th. Travels on a plane of the ecliptic: plate of earth"s orbit as it revolves the sun. Revolution takes one year at speed of 107, 280 km/hr. Rotation on its axis once every 24 hrs at velocity of 1674 km/hr. Solar activity involves solar wind: clouds of electrically charged particles reflected by earth magnetic field. Sunspots: caused by magnetic storms on the sun (have a activity cycle of 11 yrs) Insolation is the total amount of solar radiation energy received on a given surface area during a given time (amount of intercepted solar radiation) Occupies a portion of the electromagnetic spectrum.