Since Perseverance, the car-sized rover, landed on the surface of Mars on Feb. 18, interest in the red planet has skyrocketed. One of the questions that has been asked in recent weeks is where is it in the current night sky?
Mars has actually been a rather prominent evening object for several months, and in fact, at one point last October, it was the third-brightest object in the night sky.
But all of that has changed, and Mars has declined significantly in brightness since then. Nonetheless, it is still easily visible to the naked eye, and on Friday evening (March 19), you can easily identify it thanks to its proximity to our closest neighbor in space: the moon.
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At nightfall on Friday night, look more than halfway down the west-southwest horizon. There you see a crescent moon, 35% illuminated. And at the bottom right is a moderately bright yellow-orange ‘star’. But that’s not a star – it’s Mars, which is retreating further and further away from Earth and consequently continues to fade. And it may be hard to believe that it shone some 33 times brighter about 5 months ago
By Friday it will be 153.3 million miles (246.6 million kilometers) away and shine at magnitude +1.2; Mars would currently be 18th on the list of the 21 brightest stars; quite a drop since early October 2020, when it sparkled with brilliance rivaled by the beautiful planet Jupiter. In terms of apparent size, the disk of Mars is downright small; only a large amateur telescope is likely to have dark markings.
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The gap between the Moon and Mars will be equal to about 3 degrees, which is slightly greater in angular magnitude than the length of the three stars that make up Orion’s belt, the hunter.
Mars 1942 redux
Mars ‘orbit, like Venus’, has a resonance with that of the Earth, although less simple: in the time that the Earth orbits the Sun 79 times, Mars orbits nearly 42 times. So every year on Earth, Mars moves a little more than half its orbit around the sun. If it traveled exactly half way, we would pass through Mars – that is, there would be an opposition – every second year, in the same month, and in the same place. As it is, the oppositions occur about once every two years and about 50 days.
So right now Mars is repeating its behavior from 79 years ago, in 1942. What is always different is the pattern of its conjunctions with the moving series of other planets. Mars is usually involved in many more conjunctions – meaning it shares the same celestial length and appears to approach another object in the night sky – than the more distant planets, because its long orbit around our sky carries it ahead. .
Mars currently faces the stars of Taurus, the Taurus. In fact, it hovers about 7 degrees to the top left of a star that is noticeably brighter: Aldebaran, which marks the bull’s evil eye. Indeed, in late March 1942, Mars had a very similar conjunction with Aldebaran.
Just don’t confuse the planet with the star! Both objects will have a similar orange color, but on Friday night, Mars will be dimmer and closer to the moon.
Joe Rao is a teacher and guest lecturer at Hayden Planetarium in New York. He writes about astronomy for the journal Natural History, the Farmers’ Almanac and other publications. Follow us on Twitter @Spacedotcom and on Facebook.