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
04/05/2011
If you watch the horizon at just the right place and at just the right time, you can witness some spectacular juxtapositions between Earth and sky. In the above video, stars, the Moon, and even a partially eclipsed Sun were recorded rising and setting over photogenic landmarks in Greece. The inspiring video features effects on star trails that are pretty but somewhat deceiving, as stars will typically remain at nearly the same brightness as the Earth turns beneath them. Also, the time lapse nature of part of the video causes clouds to appear to jump about and fade in an unfamiliar fashion. Several stills of these scenes have appeared on APOD previously, including the partial solar eclipse over the Temple of Poseidon, cloud and star trails over a deserted church, and star trails over an old ship. Other foreground venues include an old church in Peloponnese, a stone bridge in Ioannina, a Frankish Castle in Euboea, and a picturesque sunset above Lycabettus Hill, Athens.