Mercury

1. Innermost planet in the solar system, and officially the smallest major planet since Pluto was demoted to the newly created category of dwarf planet in 2006. Diameter c. 3,050 miles. Large iron core, pitted surface, negligible atmosphere. Orbital period 88 days. Rotational period 59 days. Surface temperature ranges from minus 180 to plus 430 degrees Centigrade. No natural satellites. Gravity at surface about 38 percent of Earth gravity. Currently (in 2008) being mapped by the MESSENGER space probe.2. The planet's namesake was the messenger god of ancient Rome, well known for his winged sandals and identified with intersex identity and hermaphroditism. Greek counterpart was Hermes.3. Stage surname of lead singer Freddie of the rock group Queen. Born Farrokh Bulsara September 5th 1946, died of AIDS-related pneumonia on November 24th 1991. With his band provided much of the soundtrack for various movies, most notably Higlander. A real character.4. Metallic chemical element, liquid at room temperature, density around 13.5 grammes per cubic centimetre (or times that of water), atomic number 80. Symbol Hg, from Latin Hydrargyrum, derived from Greek form meaning "water-silver". Toxic when ingested or vapours inhaled, affects nervous system, used in barometers, thermometers and numerous other applications.