Most people know how three weary travelers completed a long journey and then famously made their appearance in a Bethlehem manger on Christmas Eve.
This Christmas Eve, three other travelers will be seen together in a rare appearance. Only this time, the travelers won’t be wise men — they are celestial bodies.
On December 24, Christmas Eve, Venus, Mercury, and the slim crescent moon will align to form a triangle, or what Space.com calls “a lovely holiday ornament low in the evening twilight sky.”
What You Need To Know About Mercury
Mercury, which is the smallest planet in our solar system and also the closest to the sun, is only slightly larger than Earth’s moon. Like the moon, Mercury also has a rocky, cratered surface.
If you were to stand on Mercury, the sun would appear more than three times as large as it does when seen from Earth. What’s more, sunlight would be as much as seven times brighter.
That doesn’t mean it’s always hot on Mercury, however. Daytime temperatures on Mercury can reach around 800 degrees because the planet is so close to the sun. The flip side of the coin is that since Mercury doesn’t have an atmosphere to hold that heat in, temperatures there can fall to 290 degrees below zero at night, according to NASA.
What You Need To Know About Venus
Venus, the second planet from the sun, is Earth’s closest planetary neighbor. It’s sometimes even called “Earth’s twin” because the planets are similar in size and density — and are two of the four rocky planets in our solar system.
There are, of course, significant differences between Venus and Earth. Most notably, Venus has a “thick, toxic atmosphere filled with carbon dioxide, and it’s perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect,” NASA explains.
Given the nature of its atmosphere, it’s only natural that Venus is also the hottest planet in our solar system, with surface temperatures of around 900 degrees. By the way, that temperature is hot enough to melt lead, NASA explains.
How To See The Celestial Display
The best time to see the moon, Venus, and Mercury together will be between 30 and 40 minutes after sunset.
Once the sun is below the horizon, you’ll first need to look for the moon low on the horizon. Interestingly, while the crescent moon’s edge will be bright, the rest of the moon will be faintly illuminated as well due to what’s called “earthshine.” That’s what happens when the dark face of the moon “catches Earth’s reflected glow and returns that light,” NASA explains.
Venus, which will be very bright, will be to the right of — and below — the moon. Mercury, which won’t be as bright, will also be to the right of — but above — the moon.
Together, the moon, Venus, and Mercury will form a triangle. If you use binoculars, all three celestial bodies will be in the same field of view.
You can use Time and Date’s Interactive Night Sky Map to see how Mercury, Venus, and the moon will line up in your location, as well as see how other planets and constellations will appear.
Wait, There’s More
If you enjoy stargazing, you’ll also want to keep an eye out for Venus and Mercury after Christmas.
The two planets have been getting closer to each other over the past few weeks as they make their way along their respective orbits. On December 28, Mercury and Venus will be in conjunction, which means they will be at their closest to each other.
“These two worlds will pass within 1.5 degrees of each other in the evening twilight,” according to EarthSky. “That’s the width of three full moons.”
To see the conjunction, you’ll want to make sure you have an unobstructed view of the horizon looking south.
Unfortunately, since the planets will be slightly above the horizon around the time of sunset, Mercury may be difficult to see. However, Venus will be very bright and easy to locate. Again, once you find Venus in the sky it will be easier to locate Mercury, especially if you use binoculars.
Importantly, Mercury and Venus won’t get this close to each other again until 2024, and they will be too near the sun to make viewing favorable then. That means you won’t want to miss this conjunction.
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