In what is known as an occultation, Mars will briefly be blocked by the moon on Tuesday morning.
Want to see a cosmic magic trick?
Look to the sky early on Tuesday, and the crescent moon will make Mars disappear. Then about an hour later, the red planet will return, as if nothing ever happened.
This celestial event is known as a Moon-Mars occultation, and it occurs from some vantage point on Earth about twice a year, according to NASA. Skywatchers from much of North and Central America will have a front-row seat to Tuesday’s occultation, and those along part of the West Coast will have an especially good view, with a chance to watch the entire show before sunrise.
This pre-dawn meetup is a useful preview of how Mars will be central to space exploration this year.
Three robotic rover missions are expected to launch to the red planet this summer — one built by NASA, a second by China and a third produced by a European-Russian collaboration. The United Arab Emirates will also launch a Mars mission, an uncrewed orbiter called Hope.
Each space program is taking advantage of Mars and Earth getting closer in their orbits around the sun, which happens about every 26 months. The spacecraft are scheduled to arrive at Mars early next year.
What is an occultation?
Astronomically speaking, an occultation is when one object moves in front of another object in the sky from our point of view.
The most famous example is a solar eclipse, when the moon momentarily slides in front of the sun. The moon also occasionally occults planets. That happens because the moon and the planets in our solar system all generally move along the same plane around the sun.
“It looks awesome because you’re watching celestial bodies appear to interact with each other,” said Jackie Faherty, an astrophysicist at the American Museum of Natural History.
Occultations can occur between the moon and planets, with pairs of planets and also when planets or the moon cross paths with far away stars. Although from our perspective you might imagine two or more heavenly bodies colliding, such objects are millions of miles apart from each other (or even separated by light years). With the right telescope equipment, the results can be jaw-dropping, like this lunar occultation of Saturn in 2019.
“It’s a really cool example and reminder of the three-dimensional world we live in,” said Dr. Faherty.
When will it occur?
The time of the event varies depending on what time zone and city you live in. Below are some general times for cities across the continental United States, according to EarthSky.
For people in New York, the Moon-Mars occultation will start around 7:36 a.m. Eastern, according to EarthSky, and will end around 9:05 a.m.
Because the event will happen after sunrise, viewers on the East Coast will have a tough time watching it and will need a telescope.
Those watching from Omaha, for example, will see Mars disappear around 5:52 a.m. local time and reappear just after sunrise around 7:18 a.m.
Skygazers in Denver, for instance, will see the occultation begin at 4:41 a.m. and end at 6:02 a.m.
In and around the Rocky Mountains, you will not need a telescope as the event will happen before sunrise and be visible with your naked eye. Dr. Faherty suggests bringing binoculars if you want to add to the experience.
Skygazers up and down the West Coast will get to see the show, but those in Southern California will be especially lucky as Mars’s disappearance and reappearance will be timed after moonrise and before sunrise.
In Los Angeles, for instance, the occultation will begin at 3:38 a.m. and end at 4:29 a.m.
Unfortunately for viewers in San Francisco and the Pacific Northwest, the moon will not be above the horizon before the beginning of the occultation. These viewers will miss the disappearance of Mars, but will be able to see its reappearance. People in San Francisco, for example, can see Mars hop out from behind the moon at 4:20 a.m.
There will be four more Moon-Mars occultations this year, although this is the only one that will be visible from North America.
For lovers of the dark skies, Dr. Faherty said that even after the occultation ends, “the action keeps going,” because the crescent moon will swing near Jupiter on Wednesday before dawn and then mosey up to Saturn on Thursday. And in October this year, Earth and Mars will be at their closest approach in two years, NASA says, which could offer strong views of the red planet to the naked eye.