orbit:    149,600,000 km (1.00 AU) from Sun
        diameter: 12,756.3 km
        mass:     5.9736e24 kg
Earth, of course, can be studied without the aid of spacecraft. Nevertheless it was not until the twentieth century that we had maps of the entire planet. Pictures of the planet taken from space are of considerable importance; for example, they are an enormous help in weather prediction and especially in tracking and predicting hurricanes. And they are extraordinarily beautiful.
                                                    Pictures of Earth