Syzygy (astronomy)

In astronomy, a syzygy (/ˈsɪzədʒi/ SIZ-ə-jee; from Ancient Greek συζυγία (suzugía) 'union, yoking', expressing the sense of σύν (syn- "together") and ζυγ- (zug- "a yoke")[1][2]) is a roughly straight-line configuration of three or more celestial bodies in a gravitational system.

If the light source, the gravitating mass and the observer stand in a line, one sees what is termed an Einstein ring.

Their tidal forces act to reinforce each other, and the ocean both rises higher and falls lower than the average.

[7] The term is also used to describe situations when all the planets are on the same side of the Sun although they are not necessarily in a straight line, such as on March 10, 1982.

[8] Because the orbits of all the planets in the Solar System (as well as the Moon) are inclined by only a few degrees, they always appear very near the ecliptic in our sky.