If you have looked up and found a single bright point sitting close to the Moon, the odds are strong it is a planet. The Moon travels along the same lane across the sky that the planets do, called the ecliptic, so every few weeks it drifts past one of them and the two hang together for a night. Four planets are bright enough to catch the eye with no equipment, Venus, Jupiter, Mars and Saturn, and the one beside the Moon tonight is almost certainly among them.
Planet or star
There is one quick test. A planet shines with a steady, calm light. A star twinkles and flickers. That is because a star is a pinpoint so far away that our moving air scatters its light, while a planet shows a tiny disc that averages the shimmer out. If the bright point beside the Moon holds a still, clean light, it is a planet. If it dances and sparkles, it is a star.
The four you will see
Venus is the brightest of all, a brilliant white point low in the west after sunset or in the east before dawn, never far from the Sun. Jupiter is the next brightest, a steady creamy white that can rule the whole sky through the night. Mars is unmistakable when it is close, a clear reddish orange. Saturn is the faintest of the four, a steady pale gold that looks like a calm, ordinary star until you notice it does not twinkle.
Why they gather near the Moon
The Sun, the Moon and all the planets ride the same narrow band across the sky because the solar system is nearly flat, like a record on a turntable, and we are looking at it edge on. The Moon is the fastest traveler along that band, lapping the sky in a month, so it is forever sliding past the slower planets. A night when the Moon sits beside a planet is called a conjunction, and it is simply the Moon catching up and passing on the shared highway.
Knowing for certain tonight
Which planet is beside the Moon changes week to week as both of them move, so no fixed answer holds for long. The reliable way is to read it from your own sky at your own hour. The live sky page shows the Moon, the planets and their positions overhead from your location right now, so you can name the bright point beside the Moon with certainty instead of a good guess.
Know what is overhead before you look up.
Conjunctions come and go in a night. Magna Earth watches the sky over your exact coordinates and tells you the evenings the Moon meets a planet, when Venus and Jupiter are at their brightest, and when the aurora reaches your latitude, so you are out at the right hour.
Read your own sky — from $14/mo