The first full moon of the year will streak across the sky on Monday night. For lucky stargazers in some parts of the world, it will also pass in front of a brighter-than-usual red Mars in an event known as an occultation.
But that’s not all there is to January skies. A new comet expected to be the brightest of the year approaches its closest approach to the Sun on Monday — though it will be tricky to spot, at least in northern skies.
What is occultation?
According to NASA, an occultation occurs when the moon passes in front of an object, such as a distant planet, making the object appear much smaller in the sky. An occultation is similar to a solar eclipse – the moon covers the sun – but on a much smaller scale.
Lunar occultations may occur several times a year, regardless of the phase of the moon. Earlier this month, people in Europe, North Africa, Greenland and parts of Russia could see the crescent moon gliding past Saturn.
What’s so special about this one?
When Mars is closer to Earth, it appears larger and brighter in the night sky. It’s approaching what’s called opposition, which occurs when Mars is on the opposite side of the Earth from the Sun. During opposition, Mars is closer than usual and its surface is completely illuminated by the Sun as seen from our world, creating a stunning view of the Red Planet.
Mars will oppose the Sun every 26 months. This year, the bill faced opposition on January 15 at 9:32 pm ET. But since November, the star has been steadily growing brighter.
How can you see the occultation of the moon?
On Monday, only people in parts of North America and Africa will be able to see the moon hiding Mars. Elsewhere, Mars will appear near the moon, a celestial phenomenon called a conjunction. In some locations, the occultation will last for more than an hour and will be visible to the naked eye, although binoculars or telescopes can enhance the view.
Events will start at different times depending on where you live. According to charts released by the International Occultation Timing Association, Mars will disappear behind the moon on Monday at 6:21 pm (Seattle), 9:16 pm in Washington, D.C., and 9:21 pm in New York City, all local times. Observers in Montreal will see the occultation at 9:25 p.m., while in Accra, Ghana, it will be seen at 4:53 a.m. before sunrise on Tuesday.
What about comets?
Comet ATLAS (known to astronomers as C/2024 G3) was discovered by the Asteroid Earth Impact Final Alert System last April and shares the same name as many other comets discovered by the telescope network, including Comet Tsuchinshan-ATLAS, which last shone in the sky.
Like all comets, C/2024 G3 is a frozen chunk of material left over from the formation of the solar system that began to melt as it approached the sun. It will reach perihelion, its closest approach to the sun, on January 13, coming within 8.4 million miles of its surface.
Some comets break up due to high temperatures. But if they survive the encounter, perihelion is expected to be when they are at their brightest—although being too close to the Sun may make them difficult to see.
How can I see Comet Atlas?
Some observers in the Northern Hemisphere have spotted Comet Atlas before sunrise, a fuzzy point with a short tail low on the eastern horizon. Due to its altitude and the light of dawn, it can be difficult to see, especially without binoculars or a telescope.
Closer to perihelion, those with an unobstructed view of the western horizon may be able to capture the comet during evening sunset. Interactive star maps like this one can help you figure out where and when to look.
If Comet Atlas survives perihelion, it will migrate into the Southern Hemisphere sky in late January and become visible in the evenings after sunset. As the comet moves away from the Sun, it will climb higher in the sky but also become dimmer each day.
