Earth

1. The most jaw-droppingly, achingly beautiful planet in the solar system. Forget Saturn. Well ... I might be just a wee bit biased. Orbits the sun once in what its inhabitants are happy to call a year at a mean distance of 93 million miles, in the course of which it rotates on its axis just over 365 times. Equatorial diameter 7,927 miles. Equal in mass to all the other planets, moons and asteroids of the inner solar system (closer in than Jupiter) put together. The innermost planet in the system to have any moons, it has of course just the one, diameter 2,160 miles, orbital distance in this epoch 238,000 miles, circles Earth about a dozen times a year, slowly receding due to tidal interactions with Earth. Earth is the densest planet in the system. Fairly massive, two-layer iron-nickel core. Seven tenths or so of the surface is covered in water oceans. Atmosphere mostly nitrogen, large proportion of free oxygen, traces of other gases such as argon, carbon dioxide and water vapour. From space, appears as a pearly globe of green-brown landmasses, blue seas, and white ice and cloud. As of 2008, the only known body in the system (or, for that matter, the Universe) to bear life. Our home. 2. Mucky powdery stuff made from grit, organic matter and water, such as may be found all over the surface of, well, the Earth. Also known as soil. If it gets wet its name is mud. Good for growing plants in. 3. An electrical connection used to dissipate excess electrical energy in the ground.