Of the eight planets in our solar system, five are visible to the naked eye: Mercury, Venus, Mars, Jupiter, and Saturn.
Known since ancient times, these naked-eye planets appear similar to stars, but they “wander” across the sky instead of staying in fixed positions relative to each other. Knowing where a planet will pop up in the sky can therefore be a tricky business.
Mercury is the hardest of the naked-eye planets to find, because it is small and faint. In addition, Mercury’s 88-day orbit means that it never travels far from the sun in our skies, so it usually gets lost in the star’s glare.
Every once in a while, though, two or more of these planets appear to converge, making them easier to spot.
Over the course of the next three evenings, from March 14 to 16, skywatchers will get a chance to find Mercury thanks to its larger, brighter sibling Jupiter.
—Images courtesy Sky & Telescope magazine
The king of all planets, Jupiter is quickly sinking lower in the evening twilight. As it does so, beaconlike Jupiter will park itself next to fainter Mercury low in the western horizon.
Both planets will be easily visible, even from light-polluted cities, to the unaided eye about 30 to 40 minutes after local sunset.
Using binoculars to scan to the right of Jupiter will definitely help in your hunt—especially in the first 15 minutes after sunset. But remember your window of opportunity is short, because the planetary duo is following close behind the sun, setting within an hour after it does.
For those that have never seen the innermost planet, this conjunction between our neighboring worlds is a great opportunity to catch a glimpse of the small, rocky world with your own eyes.
You’ll also be seeing Mercury just days before an intrepid robotic spacecraft called MESSENGER becomes the first to park itself in orbit around the little planet.
On St. Patrick’s Day, March 17, NASA’s probe will begin a year-long campaign to study the innermost planet and begin to unlock some of its mysteries.
—Illustration courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to shares his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.