Perihelion

Science / Weather / Perihelion: The point of the earth's orbit that is nearest to the sun. Although the position is part of a 21,000 year cycle, currently it occurs around January, when the earth is about 3 million miles closer to the sun than at aphelion. This term can be applied to any other celestial body in orbit around the sun. It is the opposite of aphelion.

Aphelion

Science / Astrology / Aphelion: The point in a planet's orbit that is most distant from the Sun. MORE

Apsides

Science / Tides and Currents / Apsides: The points in the orbit of a planet or moon which are the nearest and farthest from the center of attraction. In the Earth's orbit these are called perihelion and aphelion, and in the Moon's orbit, pe MORE

Anomaly

Science / Tides and Currents / Anomaly: As applied to astronomy, the anomaly is the angle made at any time by the radius vector of a planet or moon with its line of apsides, the angle being reckoned from perihelion or perigee in the directi MORE

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