The saying “when the stars align” usually alludes to something fortuitous or lucky happening: You find your true love; you buy your dream home; you finally get that raise—when the stars align.
And if the planets aligned, what then? We will find out next month when six of the solar system’s planets—Jupiter, Mercury, Uranus, Mars, Neptune, and Saturn, in that order—form a ragged but rightfully legit alignment in the predawn sky.
On June 3, just 20 minutes before sunrise, your local time, the scene will have already risen above the horizon. For those in the Northern Hemisphere looking east, starting with Jupiter popping just over the horizon, the irregular row of planets will be seen cutting diagonally upward, leaning due south toward constellation Aries, passing through Pisces, and ending westward with Saturn in a parade of planets spanning some 73 degrees of sky.
Now, speaking of such fateful things as true love or that long-awaited raise, only the stars know of these—yet certain astronomical phenomena to come from the planetary alignment are comprehensible:
One is a lunar cameo, a slim waning crescent moon on June 3 to join the lineup near constellation Aries, between Uranus and Mars.
Another occurs the next morning, on June 4. A planetary conjunction will result when Mercury steps slightly out of the planetary lineup to enter close proximity with neighboring Jupiter, just 7 degrees apart (they needn’t actually overlap to be considered a conjunction).
These extras stand to elevate the 6-planet event a step beyond.
Astronomical alignments are not an exact science as they depend on loose factors; notably in any alignment, the particular position of the viewpoint makes all the difference. Observers could be anywhere, making for indefinite and ever-changing positions, which are always elusive.
The planets do not have to line up perfectly to be considered a legitimate alignment. While razor-straight formations are almost impossible, astronomers tasked with describing these imperfect yet remarkable celestial events have managed to invent some workable definitions:
A planetary alignment is either, when several planets gather closely on one side of the sun at the same time; or a visual phenomenon when the planets appear close together in a small sky sector, as seen from the Earth.
Grouped thusly, the planets will inevitably form a rough line—the underlying geometry of the solar system ensures this. To turn the solar system on its edge would reveal that all the planets orbit roughly on a flat plane with only slight variations in the degree of tilt where Earth’s tilt is zero. So, it’s only natural that when we observe several planets from Earth they align like beads on a crooked string.
Nor are planetary alignments uncommon, particularly when there are only a few planets queuing up in the sky. But when five or more align at once, astronomers pay more attention. Notably, in the last days of December 2022, seven planets lined up for a planetary procession around Christmas, a fortunate occasion.
Now astronomers are looking forward to 2025.
“The February 2025 alignment will be a particularly good one,” Ms. Pattle said. “[S]even of the other planets in our solar system—Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune—will form a line on the sky.”
