To cap off the holiday weekend, Mars will make a rare appearance on May 30, when the planet will be at its closest point to Earth since November 2005, at 46.7 million miles away.
On average, the Red Planet is 140 million miles from Earth, though the proximity of the neighboring planets changes constantly because of their varying elliptical orbits about the sun.
But on Monday night, Mars will be close by and shining with its iconic burnt orange glow in the constellation Scorpius, says NASA. It will stay closer than 48 million miles until June 12.
Stargazers will be able to see Mars after sunset by looking towards the southeast, with a telescope or not. If using even the most basic backyard telescope, keep an eye out for the planet's icy south pole. And don’t confuse the Red Planet with Antares, a supergiant star to its left that’s bigger than the sun and, like Mars, glows in a reddish hue. A twinkle should give Antares away.
To find the star, wrote Alan MacRobert, a senior editor of Sky & Telescope magazine, "look below Mars by about the width of your fist at arm's length." He points out that the name given to the star by the ancient Greeks, means "anti-Mars" or rival of Mars, given their competition in burnt-red luminosity.
Left of Antares – again using your first – will be Saturn, resplendent in its bright, pale-yellow glow. The three will form a triangle that will be most visible during the last week of May and first week of June, says NASA.
Though Mars won’t shine as brightly as it did on May 22, when the next planet out from the sun after our own reached “opposition” with Earth. This means that the orbits of the two planets aligned them in a way where Mars and the sun flanked Earth on opposite sides forming a straight line. Opposition of Mars happens every 26 months. Saturn will reach its own opposition with Earth on June 3, when it will be 840 million miles from here.
Given its further distance from the sun and the different forces of gravity influencing it, Mars orbits the sun much more slowly and on a different plane than does Earth. This is why it reaches opposition only once every 26 months, when it happens to briefly sync up with Earth’s tighter and thus faster orbit around the sun.
The shape of Mars’s path around the sun is also more elliptical than Earth’s – and is actually elongating over the centuries – so the distance between the two planets changes. This means that some oppositions, which can happen anywhere along Mars's orbit, bring the worlds closer together than others.
When it happens while the Red Planet is closest to the sun, which is called "perihelic opposition," Mars is especially close to Earth.
The last close encounter of this type was in August 2003, when Mars was 35 million miles from Earth, the closest the two planets had been in almost 60,000 years. Unfortunately for today’s stargazers, this won’t happen again until 2287.