Annular Solar Eclipse by Ensign February 20, 2021 0 An annular solar eclipse happens when the Moon covers the Sun's center, leaving the Sun's visible outer edges to form ...
Antimatter by Ensign February 20, 2021 0 Matter consisting of particles with charges opposite that of ordinary matter. In antimatter, protons have a negative charge while electrons ...
Antipodal Point by Ensign February 20, 2021 0 A point that is on the direct opposite side of a planet.
Apastron by Ensign February 20, 2021 0 The point of greatest separation of two stars, such as in a binary star system.
Aperture by Ensign February 20, 2021 0 The diameter of a telescope's main lens or mirror and the scope's most important attribute. As a rule of thumb, ...
Aphelion by Ensign February 20, 2021 0 Aphelion is the point farthest away from the Sun on Earth's elliptical orbit.
Apogee by Ensign February 20, 2021 0 The point in the orbit of the Moon or other satellite where it is farthest from the Earth.
Apparent Magnitude by Ensign February 20, 2021 0 The apparent brightness of an object in the sky as it appears to an observer on Earth. Bright objects have ...
Asteroid by Ensign February 20, 2021 0 A small planetary body in orbit around the Sun, larger than a meteoroid but smaller than a planet. Most asteroids ...
Asteroid (Minor Planet) by Ensign February 20, 2021 0 A solid body orbiting the Sun that consists of metal and rock. Most are only a few miles in diameter ...
