Click anywhere on this site, and you’ll likely run into a measurement in terms of light-years, solar masses, astronomical units, or arcminutes. These units are unique to astronomy, and all can be ...

Appearances aside, the stars are not eternal and the planets do not move with clockwork precision. For these reasons, one astronomer is proposing that his colleagues ditch the astronomical unit, or AU ...

One of the stalwart units of astronomy just got a makeover. The International Astronomical Union, the authority on astronomical constants, has voted unanimously to redefine the astronomical unit, the ...

If you guessed the astronomical unit, you are correct. The au — the rough distance between the Earth and the Sun — was previously determined by a confusing calculation (“the radius of an unperturbed ...