Are you ready to see a truly odd astronomical event?
As seen from North America, the full “Cold Moon” will move across Mars, covering the red planet for an hour. The event will happen relatively low in the eastern night sky in prime time on Wednesday, December 7, 2022.
Astronomers call this event an occultation. Here are seven things you need to know about it—and how to enjoy it:
1. Mars will be at its best since 2020
There is something very special about the timing of this occultation of Mars. It will happen just as fourth planet Mars reaches its bright opposition—a cosmic moment every 26 months when third planet Earth undertakes it on the inside. Earth will be positioned directly between Mars and the Sun and Mars is thus at it biggest, brightest and best in Earth’s night sky.
2. There’s an ‘occultation zone’
Much—but not all—of North America, northern Mexico, most of Europe and northern Africa will be able to watch this rare and special occultation.
3. It will happen in prime time in North America
The occultation takes place for North Americans in the evening hours of December 7, 2022. Here are the disappearance and reappearance times for eight cities in the occultation zone in North America:
- Los Angeles, CA: 6:30 p.m. PST-7:30 p.m. PST
- Seattle, WA: 6:52 p.m. PST-7:51 p.m. PST
- Vancouver, BC: 6:55 p.m. PST-7:52 p.m. PST
- Phoenix, AZ: 7:32 p.m. MST-8:31 p.m. MST
- Denver, CO: 7:45 p.m. MST-8:48 p.m. MST
- St. Louis, MO: 9:06 p.m. CST-9:52 p.m. CST
- Chicago, IL: 9:11 p.m. CST-10:05 p.m. CST
- Toronto, ON: 10:29 p.m. EST-11:18 p.m. EST
4. In Europe it’s a pre-dawn event
On Thursday, December 8, 2022 the Moon will move in front of the red planet in the western sky. As seen from London, Mars will disappear at 04:58 GMT and reappear at 05:59 GMT.
5. Moon-skims-Mars will also be worth watching
“If you’re outside this occultation zone, don’t despair,” said Diana Hannikainen, Observing Editor at Sky & Telescope. “The sight of the Red Planet skimming below the lunar disk will be an unforgettable experience nevertheless.”
Here are times for when Mars is closest to the Moon outside the occultation zone in North America:
- New Orleans, LA: 9:11 p.m. CST
- Huntsville, AL: 9:23 p.m. CST
- Miami, FL: 10:16 p.m. EST
- Atlanta, GA: 10:26 p.m. EST
- Washington, DC: 10:46 p.m. EST
- New York, NY: 10:56 p.m. EST
- Boston, MA: 11:01 p.m. EST
6. You should watch it disappear … then reappear
Go outside on December 7/8 at the correct time and look east. You’ll see with naked eyes the full “Cold Moon” as well as some notable objects such as the Pleiades star cluster above. Mars will be left or lower left of the bright lunar disk and as the occultation begins the Moon will be traveling leftward in the sky toward Mars, according to Sky & Telescope. It will take the Moon about a minute to move across and block all of Mars. As little as a minute or as much as an hour later Mars will re-emerge on the right side side of the lunar disk.
7. Occultations are not rare
Since the planets in the solar system all orbit the Sun on roughly the same plane and the Moon orbits Earth on almost the same plane, it’s not particularly unusual for the Moon to block a planet for some minutes. However, the fact that this is a full Moon—and that Mars is also “full”—makes it rare and special.
Don’t despair if there are clouds, you’re working or otherwise unable to view this occultation of Mars. Luckily, there’s another one coming up just as Mars reaches its next opposition. On the evening of January 13, 2025—two days before opposition—a similar event will occur.
Wishing you clear skies and wide eyes.