The Moon
The Moon is Earth’s only natural satellite—a rocky, cratered body about one‑quarter the diameter of Earth, orbiting at an average distance of approximately 384,400 km. It influences tides, stabilizes Earth’s axial tilt, and was formed about 4.5 billion years ago following a collision between Earth and a Mars-sized object.
Source: science.nasa.gov
APODs including "The Moon"
Rollback from GRAIL's Rocket
10/09/2011
This dramatic time-lapse photo traces a 20 minute long, late evening rollback of the lighted Mobile Service Tower at Cape Canaveral Air Force Station Launch Complex 17. Twin spacecraft are snug inside the 13 story tall Delta 2 rocket poised for launch. The duo will journey to the Moon on NASA's Gravity Recovery and Interior Laboratory mission, GRAIL, using precision formation flying to map the Moon's gravity field. The scene was captured prior to the first launch attempt, canceled due to upper level winds, on September 8. Further launch opportunities for GRAIL begin this morning, September 10. The GRAIL launch is the last one planned from Complex 17 on Cape Canaveral's oldest still active pad, in use since 1957.