The moon is lining up to lead a parade of planets across the predawn sky starting April 23.
In advance of an unusual alignment of the five visible planets in the solar system, four planets are lining up behind the moon like ducks in a row. On April 23, Saturn, Mars, Venus and Jupiter will all be visible above the horizon in the early morning hours in the northern hemisphere.
Mercury will join this parade of planets in mid-June.
When the planets align
Planetary alignments occur when the planets’ orbits bring them to the same region of the sky, when viewed from Earth. These planetary alignments are not rare, but they’re not regularly occurring, either: The last time five planets aligned in the night sky was in 2020, preceded by alignments in 2016 and 2005.
These alignments take time to develop. Venus, Mars, and Saturn have been night-sky neighbors since late March. On April 4 and 5, they came so close together, when viewed from Earth, that Mars and Saturn appeared less far apart than the width of the full moon in the southeast early morning sky.
Jupiter turned the trio into a foursome in mid-April. The moon will appear in its last quarter phase to Saturn’s right on April 23. Mars will be an orange dot below and to the left of Saturn, while Venus will be a brighter light below and to the left of Mars. Jupiter will be lowest and leftmost in the sky.
The way to tell the planets from the stars in the sky is by the light, said Michelle Nichols, the director of public observing at Chicago’s Adler Planetarium.
“Stars twinkle,” Nichols told Live Science. “Planets don’t.”