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"
A Lunar Eclipse Over an Indian Peace Pagoda
14/12/2011
Our Moon turned red last week. The reason was that during December 10, a total lunar eclipse occurred. The above digitally superimposed image mosaic captured the Moon many times during the eclipse, from before the Moon entered Earth's shadow until after the Moon exited. The image sequence was recorded over a Shanti Stupa Peace Pagota near the center of New Delhi, India. The red tint of the eclipsed Moon was created by sunlight first passing through the Earth's atmosphere, which preferentially scatters blue light (making the sky blue) but passes and refracts red light, before reflecting back off the Moon. Differing amounts of clouds and volcanic dust in the Earth's atmosphere make each lunar eclipse appear differently. The next total lunar eclipse will occur only in 2014. Discovery + Outreach: Graduate student research position open for APOD