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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"

Moonrise, Cape Sounion, Greece

23/06/2005

Moonrise, Cape Sounion, Greece
Image Credit: Anthony Ayiomamitis / NASA APOD

The Moon was full this month on June 22nd, only a day after the northern hemisphere's summer solstice. Since this solstice marked the northernmost point of the Sun's annual motion through planet Earth's sky, the full Moon rising near the ecliptic plane opposite the Sun was at its farthest south for the year. Only a month earlier, on May 23rd, astronomer Anthony Ayiomamitis recorded this picture of another southerly full Moon rising above Cape Sounion, Greece. The twenty-four hundred year old Temple of Poseidon lies in the foreground, also visible to sailors on the Aegean Sea. In this well-planned, single exposure, a long telephoto lens makes the Moon loom large, but even without optical aid casual skygazers often find the full Moon looking astonishingly large when seen near the horizon. That powerful visual effect is known as the Moon Illusion.