Jupiter and Saturn will come within 0.1 degrees of each other, forming the first visible “double planet” in 800 years

Before 2020 comes to a close, Jupiter and Saturn will be so close that they will appear to form a “double planet.” The great conjunction, as the planetary alignment has come to be known, hasn’t occurred in nearly 800 years. 

When their orbits align every 20 years, Jupiter and Saturn get extremely close to one another. This occurs because Jupiter orbits the sun every 12 years, while Saturn’s orbit takes 30 years — every couple of decades, Saturn is lapped by Jupiter, according to NASA.  

However, 2020’s conjunction is especially rare — the planets haven’t been observed this close together since medieval times, in 1226.

“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,” Rice University astronomer Patrick Hartigan said in a statement. “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.”

Aligning with the solstice on December 21, 2020, the two planets will be just 0.1 degrees apart — less than the diameter of a full moon, EarthSky says. The word “conjunction” is used by astronomers to describe the meeting of objects in our night sky, and the great conjunction occurs between the two largest planets in our solar system: Jupiter and Saturn. 

The planets will be so close, they will appear to overlap completely, creating a rare “double planet” effect.

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Jupiter and Saturn will come within 0.1 degrees of each other on December 21, 2020, during what is known as the “great conjunction.” 

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How to watch the great conjunction

During the last great conjunction in 2000, Jupiter and Saturn were so close to the sun that the event was difficult to observe. But skywatchers should have a clearer view of the celestial event this time around. The great conjunction will be shining bright shortly after sunset, low in the southwestern sky, as viewed from the Northern hemisphere, NASA says. 

Through the entirety of December, skywatchers will easily be able to spot the two planets. For the next three weeks, you can look up each evening to watch them get closer and closer in the sky. 

Jupiter currently appears brighter than any star in the sky. Saturn is slightly dimmer, but still just as bright as the brightest stars, with a recognizable golden glow. 

Saturn will appear just to the east of Jupiter, and will even look as close to the planet as some of its own moons. Unlike stars, which twinkle, both planets will hold consistent brightness, easy to find on clear nights. 

The event is observable from anywhere on Earth, provided the sky is clear. “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. 

The planets will appear extremely close for about of month,

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Zeta May Be Forming In The Caribbean

The 2020 Atlantic hurricane season is still upon us. Hurricane Epsilon is heading off into the North Atlantic, but there is no rest for hurricane forecasters. The National Hurricane Center is now watching a new area of interest in the Caribbean Sea. If it develops into a tropical storm, it will be named Zeta. Would it be odd for this time of year? The answer is complicated.

Before I delve into the answer, let’s take a look at the current status of Invest #95L, the technical name given to the storm system of interest by NOAA. According to the National Hurricane Center Friday afternoon update, “Satellite images and radar data indicate that the broad area of low pressure located just west of Grand Cayman Island is gradually becoming better defined.” Forecasters give the storm a 70% chance of further development within the next 2 to 5 days. Whether it becomes Zeta or not, significant rainfall will be possible over the weekend in Cuba, Jamaica, southern Florida, and parts of the Bahamas. The ultimate path of the storm (towards Florida or further into the Gulf of Mexico) will depend on how it interacts with a cold front sweeping eastward in the United States. If you live in Florida or along the eastern Gulf of Mexico, watch the forecast carefully over the weekend.

Ok, let’s get to the question about “odd.” It is certainly not odd to have tropical cyclones at this time of year. The map below shows a climatology of tropical cyclone origin points in late October over the period 1851 to 2015. If Zeta forms, it is within a region of the Atlantic basin where we tend to see development. However, here is where things get a bit more complicated.

If Zeta forms, it will be only the second time in history that we have used the name Zeta. That is odd. As you recall, when the hurricane name list is exhausted, the Greek alphabet is used. The only other time this was employed was 2005. That year, Zeta, which is not the last letter in the Greek Alphabet, was reached. There is one major difference between 2005 and 2020. In 2005, Tropical Storm Zeta was named on December 30th and dissipated in January. According to a Tweet by Colorado State University hurricane expert Phil Klotzbach, “Current record for earliest 27th Atlantic named storm formation is November 29, 2005” He goes on to explain that the previous record was for the 2005 version of Epsilon but an additional October storm was added after the season in 2005. This oddity explains why the 27th named storm was Epsilon in 2005. The 27th named storm in 2020 will be Zeta (if it develops).

In a season of records for the 2020 Atlantic hurricane season, CIRES research scientist Sam Lillo points out another

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