Earth goes between the sun and Mars about every two years. That’ll happen around 6 UTC (12 a.m. CST) on December 8. This is Mars’ opposition, an event we astronomers wait for, and enjoy.
A full moon happens every month. And this month’s full moon comes just a couple of hours before Mars’ time of opposition, at 04:08 UTC on December 8, 2022 (10:08 p.m. CST on December 7).
A full moon appears full to us because it’s opposite the sun from Earth. And Mars – or any outer planet – is opposite the sun from Earth at opposition. So it’s no surprise that this month’s full moon is somewhere near Mars. Planets are always near the full moon sometime around their time of their oppositions.
What’s so special in 2022 is that these events – full moon and Mars’ opposition – happen so near each other in time. Around 4 to 6 UTC on December 8, the sun, Earth, moon and Mars will be nearly in a line.
And, what’s more, the full moon won’t just pass near Mars in the sky. Its path across the sky (which varies in an 18-year cycle) is such in 2022 that it’ll pass directly in front of Mars.
I’m really curious if we’ll continue to see Mars with the unaided eye right up to the moon’s edge. I suspect we will. Also, at what point will the planet disappear from view as it dips behind the moon? Keep those binoculars handy! Telescopic observers will get fabulous views, especially those living within the southern graze zone, where the moon will partially occult the planet.
