Mars and the Moon team up for a bit of stage magic tomorrow morning. As seen from parts of the United States, Mars will disappear — hidden behind the crescent Moon.
Such an event is called an occultation. It happens because the Moon and planets all stay close to the ecliptic — the Sun’s path across the sky. Their exact paths diverge from the ecliptic by a few degrees, though. So the geometry has to be just right for the Moon to pass in front of a planet and block its light. As a result, such encounters are rare.
In the past, occultations were important ways to learn about Mars. Precise timing of the event helped astronomers measure the planet’s diameter, for example, and refine models of its orbit around the Sun. Today, spacecraft provide much better measurements, so occultations are less important.
They’re still interesting to watch, though. This one will be visible across much of the western half of the United States. The view will be best from the Mountain Time Zone, where the Moon will cover Mars by around 4:45 a.m. By then, the two worlds will be high enough in the sky for you to watch as the Moon passes between Earth and Mars.
Parts of the Central and Pacific zones will see at least part of the occultation. But the east will miss out because the Sun will be rising by the time Mars vanishes.
Those who miss the occultation, though, will still see a beautiful conjunction, with orange Mars quite close to the crescent Moon.
Script by Damond Benningfield