Star planets: an incredibly rare “Christmas star” to appear for the first time in 800 years


ATLANTA (CNN) – The two largest planets in our solar system are getting closer than they’ve been since the Middle Ages, and it’s happening just in time for Christmas.
So there are things to look forward to in the final month of 2020.

On the night of December 21, the winter solstice, Jupiter and Saturn will appear so closely aligned in our sky that they will look like a double planet. This narrow approach is called a conjunction.

“Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare due to the proximity of the planets,” said the Rice University astronomer and professor of physics. and astronomy Patrick Hartigan in a statement.

“We would have to go back to dawn on March 4, 1226 to see a closer alignment between these objects visible in the night sky. ”

If you are an astronomer, you have probably noticed that Jupiter and Saturn are getting closer since the summer. And they are currently visible in our night sky, getting closer and closer to each other.

But between December 16 and 25, they will become even more comfortable. Look for the Jupiter-Saturn conjunction low in the western sky for about an hour after sunset each evening during this time.

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

Although these two planets may seem close, they are still hundreds of millions of kilometers apart, according to NASA.

A view showing how the Jupiter-Saturn conjunction will appear in a telescope pointed towards the western horizon at 6 p.m. CST, December 21, 2020. The image is adapted from graphics from open source planetarium software Stellarium. (This work, “jupsat1”, is adapted from Stellarium by Patrick Hartigan, used under GPL-2.0, and provided under CC BY 4.0 courtesy of Patrick Hartigan) (Photo: Patrick Hartigan, Rice University astronomer)

Hopefully a clear sky as the conjunction will be visible around the world, with the best prospect for those near the equator.

“The farther north a viewer is, the less time they will have to see the conjunction before the planets sink below the horizon,” Hartigan said.

The planets will be bright enough to be seen at dusk, which may be the best time for many American viewers to observe the conjunction.

“By the time the sky is completely dark in Houston, for example, the conjunction will be just 9 degrees above the horizon,” Hartigan said. “It would be manageable if the weather permitted and you had a clear view to the southwest. ”

If you are in New York or London, or along those latitudes, try to spot the conjunction right after sunset. Waiting an hour after sunset will only bring the planets closer to the horizon, making them harder to spot.

The best conditions for seeing this astronomical event will include a clear southwest horizon and no low clouds in the distance, Hartigan said. Binoculars or a telescope can help you distinguish planets. A telescope would make it possible to see Saturn’s rings and the brightest moons of both planets, he said.

If you miss this conjunction and want to see the planets with the same proximity, just higher in the sky, it won’t happen until March 15, 2080 – and not yet until 2400.

Between 0 and 3,000 CE, or common epoch, only seven conjunctions were or will be closer than this one – and two of them were too close to the sun to be seen without a telescope, according to Hartigan. So, yes, this is an incredibly rare event.

The-CNN-Wire ™ and © 2020 Cable News Network, Inc., a WarnerMedia Company. All rights reserved.


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