A geomagnetic storm is predicted to make nightfall next week—but before the Northern Lights spectacle, experts are alerting space enthusiasts to another celestial event that’s set to occur during the twilight hours of June 3. Six planets— Jupiter, Mercury, Uranus, Mars, Neptune, and Saturn—will align in a small sector in what some are calling the “parade of planets.” And Star Walk reports that a phenomenon of this kind won’t happen again until Sept. 2040.
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Stargazers first heard about the rare display via a Star Walk social media post. According to the planetarium app, whose Sky Tonight tool can be used to view the parade, a planetary alignment is an “astronomical event when planets gather closely on one side of the Sun at the same time, as seen from above the Solar System.”
“Some people think the Solar System planets can form a straight line as viewed from the Sun. However, the planets cannot achieve full alignment in three dimensions,” explains Star Walk. “Even a looser grouping in one quadrant (a 90-degree sector) is extremely rare: all planets gather in one quadrant only 7 times in the current millennium.”
Around 3:00 a.m. local time on June 3, those north of the equator will get to see the parade of planets up close. As with any celestial encounter, the best viewings occur in areas with little obstruction (like pollution, tall buildings, trees, and city lights). Although onlookers will be able to spot some of the planets without additional help, tools like binoculars are required if you hope to go six for six.
“Mercury, Mars, Jupiter, and Saturn may be spotted with the naked eye, but you'll need a telescope or high-powered binoculars to see Neptune and Uranus,” says Star Walk.
If the sky is clear and all goes to plan, some are confident that bystanders will be treated to a dazzling sight. However, broadcast meteorologist Joe Rao isn't as optimistic. In his Space column, Rao warns that “seeing some of these planets at all will be problematic.”
"People who plan to rise early and step outside on June 3 expecting to see the bloated disk of Jupiter or the rings of Saturn in a single glance will be, at the very least, quite disappointed," Rao wrote, citing the planetary alignment as a “celestial falsehood.”
According to Rao, the parade will kick off around 2:00 a.m. local time when Saturn begins its ascent in the eastern sky. Without binoculars, the planet will appear as “a relatively bright light glowing with a yellowish-white tint.”
Due to their proximity to the sun, Mercury and Jupiter will also be difficult to spot and will likely be “masked by the brilliant glow of morning twilight,” Roa added. They’ll hang “exceedingly low to the east-northeast horizon” and are predicted to rise 30 minutes before sunrise.
“So, unless you have a nice flat horizon, with no obstructions (like distant buildings or trees) you can probably forget making a sighting of the solar system's smallest planet (Mercury) next to the largest planet (Jupiter),” said Rao.
Uranus will also be nearly invisible, especially to the unaided eye. “Uranus will rise only about an hour before sunrise, when morning twilight will be well advanced. So, like Mercury and Jupiter, there's no real chance of seeing Uranus either,” per Rao. If the sky is exceptionally clear and dark, the odds of a sighting increase.
Mars will be a “relatively bright orange light,” falling to the right of the moon, which will take on the shape of a waning crescent, wrote Rao. Conversely, Neptune will be one of the hardest planets to spot, so plan to use binoculars or a telescope.
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While the parade of planets may be less dazzling than expected, fans can still catch bold displays of the moon, Mars, and Saturn. With the right resources like binoculars, a telescope, or a stargazing app, onlookers may also be able to catch a glimpse of some of the harder-to-see planets.
“So, if you step outside at around 3:30 or 4 a.m. on Monday morning, don't expect to be awed by the sight of a planet parade. What you will likely see is a crescent moon and a bright orange 'star' shining to its right (Mars) and farther off to the right will be another relatively bright 'star' glowing with a yellowish-white hue (Saturn),” Rao explained.
