Level 1 Level 3
Level 2

Astronomy A-Z


14 words 0 ignored

Ready to learn       Ready to review

Ignore words

Check the boxes below to ignore/unignore words, then click save at the bottom. Ignored words will never appear in any learning session.

All None

Ignore?
Absolute Magnitude
A scale for measuring the actual brightness of a star.
Absolute Zero
The temperature at which the motion of all atoms and molecules stops.
Accretion
When dust and gas accumulates to bigger bodies.
Apogee
The point in the orbit of the Moon or other satellite where it is farthest from the Earth.
Altitude
The angular distance of an object above the horizon.
Apparent Magnitude
The apparent brightness of an object in the sky as it appears to an observer on the Earth.
Aphelion
The point in the orbit of a planet or other celestial body where it is farthest from the Sun.
Asteroid
A small rocky body orbiting the sun. Large numbers of these, ranging enormously in size, are found between the orbits of Mars and Jupiter, though some have more eccentric orbits.
AU
A unit of measure equal to the average distance between the Earth and the Sun.
Atmosphere
A layer of gases surrounding a planet, moon or star.
Aurora
A glow in a planet's ionosphere caused by the interaction between the planet's magnetic field and charged particles from the Sun.
Axis
An imaginary line through the center of rotation of an object.
Azimuth
The angular distance of an object around or parallel to the horizon from a predefined zero point.
Perihelion
The point in the orbit of a planet or other celestial body where it is closest to the Sun.