Lucky residents of southeast Asia got a chance to watch the moon pass in front of the red planet Mars on April 17, 2021. Astronomers call this event an occultation. The occultation of Mars was captured by EarthSky friends and photographers in India. Mars slipped under the unlit limb of the moon, disappearing behind Earth’s satellite for approximately 30 minutes, before reappearing from under the lit crescent portion of the moon.
The moon occults Mars every so often, but not many of these events are easy to see. You have to be at the right spot on the globe for the two objects to align just right from your point of view, much like an eclipse of the sun. In addition, it needs to be nighttime so that you can see the small dot of Mars as it disappears behind the moon, and Mars and the moon must both be above the horizon. Therefore, the recent lunar occultation of Mars was a lucky sight indeed.
Two more occultations of Mars will happen this year, on December 3 and 31, 2021. Yet, neither one of these occultations prevails as long in a nighttime sky. The December 3 occultation of Mars will be visible in northeast Asia, whereas the December 31 occultation of Mars will be visible to a small swath of residents in Australia.
Bottom line: Some lucky sky watchers saw the moon pass in front of Mars on Saturday, and photographers shared their images with EarthSky readers!
Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. She began her career at Astronomy Magazine, and she has made regular contributions to AstronomyToday and the Sierra Club, among other outlets. Her children’s picture book, Solar System Forecast, was published in 2012. She has also written a young adult dystopian novel titled A Different Sky. When she is not reading or writing about astronomy and staring up at the stars, she enjoys traveling to the national parks, creating crossword puzzles, running, tennis, and paddleboarding. Kelly lives with her family in Wisconsin.