A great celestial meeting is planned in the skies of Earth throughout the month of June. Skywatchers will have a rare chance to see all the major planets of our solar system grouped together, with the moon also joining in the festivities from June 17-27.
This rare alignment includes the five planets easily spotted with the naked eye: Mercury, Venus, Mars, Jupiter and Saturn. Each is bright enough to be seen even in light-polluted urban skies, with bright Venus being the brightest and Mercury the faintest. Our closest planets will appear arranged in the sky in the same order as their distance from the sun.
Astronomers call these close planetary encounters conjunctions. Having two or three planets packed together isn’t that uncommon, but the last time we saw a conjunction of the five brightest planets was in December 2004.
The more distant Uranus and Neptune will also cluster in the same area, although the two ice giants are harder to spot, requiring the use of binoculars. Scan between Venus and Mars to find green-tinted Uranus, and blue Neptune can be found between Jupiter and Saturn in the sky.
This planetary alignment can be glimpsed by the vast majority of the world’s population, but some will be better positioned than others. For those in northern latitudes, above cities like New York and London, the planet closest to the sun, Mercury, will be close to the horizon and could be swept away in the glow of dawn. In these regions, the other planets will also embrace the eastern horizon, which will make it a bit difficult to see all the planets easily.
As the month progresses, however, Mercury will appear higher in the sky, making it easier to spot. For observers even further north, such as those in Scandinavia and northern Alaska where the sun never sets at this time of year, the planets will not be visible at all.
The best views will be centered around the tropics and in the southern hemisphere, where planets will rise higher in the sky before dawn. But no matter where you are, the best recommendation is to look for a clear view of the eastern horizon about an hour to 30 minutes before local sunrise.
The panorama will be particularly impressive because the planets will appear tight against each other. And if you miss this show, you will have to wait until 2040 to have another chance.
The moon lights the way
To find the planets, viewers need only look at the bright crescent moon. Beginning June 17, when it will appear near Saturn, our natural satellite will serve as a landmark, posing with each planet overnight.
The most significant dates include June 18, when the moon will be closest to Saturn, and June 20, when the moon will associate with Neptune. June 21 sees the moon rejoin Jupiter and on June 22 the moon meets Mars. The moon pairs with Uranus on June 24, and savvy skywatchers will also notice that it will appear exactly halfway between Venus and Mars. On June 26, the moon will have an eye-catching close encounter with the brightest planet in the sky, Venus, and then finally end its visits with Mercury on June 27.
A celestial traffic jam
While this parade of planets will seem crammed into a small patch of sky, the distant worlds are of course spread out over a vast expanse of space, separated from each other by millions of miles. It is our perspective on Earth that makes them seem so closely positioned.
This great spectacle from the sky is easy to see with the naked eye, but a well-held pair of binoculars will give you a better view. Hold your glass to cream-colored Jupiter and it will reveal its four largest moons. Small telescopes reveal all of the worlds as discs, highlighting details like the cloud bands on Jupiter and Saturn’s famous rings.
Both Uranus and Neptune are much fainter than the rest of the planets, so you’ll probably need binoculars just to catch a glimpse of them as fuzzy, greenish-blue points of light. But a small telescope will begin to reveal more details about these icy giants on the outskirts of the solar system – an incredible sight given that Uranus is more than 2.8 billion kilometers from Earth, while Neptune is close by. 2.8 billion kilometres.
Get your views on now, because the planetary party won’t last long. Over the next few months, the planets will move away from each other, spreading across the sky. By late summer in the northern hemisphere, both Venus and Saturn will have retreated from the morning sky.