Don’t Miss This Month’s Rare Planetary Alignment
Five planets will appear together in the sky—all visible to the naked eye
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Step outside this week into the chilly predawn to see the planet Mercury peak over the horizon. Then trace an arc across the sky to pick out Venus, Saturn, Mars and Jupiter. All five will be visible together for the first time since 2005.
The latter four planets have been shining in the early morning since the beginning of the year, writes Tanya Hill for The Conversation. "It is the appearance of Mercury that makes the family complete," she adds. Take in the spectacle sometime around January 20, depending on your location.
Mercury usually hangs close to the horizon and is the most difficult to see. But it will gradually cross higher in the sky and by early February it will be easier to spot.
Starting January 28, the waning moon will travel along the line of planets, starting out at Jupiter and resting near Mercury by February 7. Venus and Saturn will dance in particularly close conjunction on February 9, report Bruce McClure and Deborah Byrd for EarthSky.org.
Since each planet orbits at different distances from the Sun and takes different periods of time to complete a year, this kind of alignment in the Earth's sky is rare. The fact that they do stack up in a line is visual proof that the planets do orbit on roughly the same plane, Hill writes.
“There are only a few amazing things in the night sky that can be seen without any equipment,” Alan Duffy, a research fellow at Swinburne University in Melbourne tells Anne Johnson of Australian Geographic. The planetary alignment is one of of them, and worth an early rise. Duffy does caution that some people may have to travel farther than their front stoop to get an unobstructed view of the horizon. Trees, buildings, and city lights can all block the rare views.
So make sure you prepare for the show, and figure out when Mercury will rise near you using the United States Naval Observatory's webpage. Hope for clear skies and bundle up because this may be the best view of the five planets aligned for quite a while. According to EarthSky.org, though the group will gather again in August, only those in the Southern Hemisphere will really get to see the next show.