“Christmas Star” Will Be Visible For First Time In 800 Years This Week

Astronomers have noticed that this year, Jupiter and Saturn will appear closer together from the planet Earth than they have in hundreds of years. A press release from researchers at Rice University says that the planets will appear to create what some are calling a "Christmas Star."

It will appear in the sky just after sunset on the evening of Dec. 21,  according to researchers.

“Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to one another,” said Rice University astronomer Patrick Hartigan in the press release.

“You’d have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky,” he added.

Since the summer, the two planets have been approaching one another more closely than in many generations, From Dec. 16-25, the two will be separated by less than the diameter of a full moon.

“On the evening of closest approach on Dec 21 they will look like a double planet, separated by only 1/5th the diameter of the full moon,” Hartigan, a professor of physics and astronomy said. “For most telescope viewers, each planet and several of their largest moons will be visible in the same field of view that evening.”

The event will be observable anywhere on the planet as long as the weather or clouds don't get in the way. However, the best places to view this phenomenon will be closer to the equator.

Hartigan said the planetary pair will appear low in the western sky for about an hour after sunset each evening.

“The further north a viewer is, the less time they’ll have to catch a glimpse of the conjunction before the planets sink below the horizon,” Hartigan said.

Photo: Rice University

“By the time skies are fully dark in Houston, for example, the conjunction will be just 9 degrees above the horizon. Viewing that would be manageable if the weather cooperates and you have an unobstructed view to the southwest,” he added.

In places like New York or London, the Christmas Star will be visible at about 7.5 degrees and 5.3 degrees from the horizon. what this means is that viewers who live in these areas, or along a close latitude have their best chances of seeing the Christmas Star just after sunset.

The team estimates that the planets will not be this close again until March 15, 2080, and after that, the next time will be 2400.

In reality, these planets aren't close together in the sense that they are on some type of collision course, but rather, from the perspective of people here on Earth, they appear close together because of the exact positions that all of the planets end up at a given time. As the image above shows, the two planets are still nowhere near each other, it just appears that way to us.

Mark Horowitz is a graduate of Brandeis University with a degree in political science. Horowitz could have had a job at one of the top media organizations in the United States, but when working as an intern, he found that the journalists in the newsroom were confined by the anxieties and sensibilities of their bosses. Horowitz loved journalism, but wanted more freedom to pursue more complex topics than you would find on the evening news. Around the same time, he began to notice that there was a growing number of independent journalists developing followings online by sharing their in-depth analysis of advanced or off-beat topics. It wasn't long before Horowitz quit his internship with a large New York network to begin publishing his own material online.