Moon

Moon

The Earth's only natural satellite. The moon has a cold, dry orb covered with many lunar craters and strewn with rocks and dust. The moon has no atmosphere. But recent lunar missions have found plenty frozen water on the moon.

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Moon

Moon rise

Astronomy; Moon

Similar to sunrise, it is the first appearance that the Moon makes over the Earth's horizon, and as such it is relative to the geographical position of the observer.

New Moon

Astronomy; Moon

The phase of the Moon when it is directly between the Earth and the Sun. Because sunlight is hitting only the far side of the Moon, it appears dark from the Earth. Reflected light from Earth can ...

Neap tide

Astronomy; Moon

When the Moon is at its first quarter or last quarter, its gravitationsl forces are partially cancelled out by the Sun. This leads to a lower high tide than normal.

Aphelion

Astronomy; Moon

The point in a planet's orbit around the Sun when it is farthest from the Sun (opposite of perihelion).

Visual diameter

Astronomy; Moon

The diameter of a distant object as measured by the angle formed from a point representing an observer and the outer edges of the object.

Angular diameter

Astronomy; Moon

The diameter of a distant object as measured by the angle formed from a point representing an observer and the outer edges of the object.

Annular eclipse

Astronomy; Moon

An solar eclipse where the Moon is between the Sun and the Earth, but with the Moon appearing smaller than the Sun to the observer, leaving a bright ring around the circumference of the Moon. An ...