Jupiter, Saturn coming together (sort of)

Our Winter Solstice, or the first day of winter, is on Dec. 21. On that date, our largest planet, Jupiter, and its neighbor Saturn will make a very rare conjunction.

From our perspective on Earth, both planets will come very close to one another. In fact, only a tenth of a degree will separate the two, which is about a fifth of the width of the moon. It will appear as if the planets are almost touching one another and may even look like a single planet.

According to earthsky.org, the last time these two planets were this close was way back in 1623, so this will be a once-in-a-lifetime event as the next major conjunction between the two planets will not occur until March 15, 2080.

Saturn takes 30 years to go around the sun whereas Jupiter takes 12 years for one full orbit. Although both planets do have a conjunction every 20 years, they will not be this close again for another 60 years.

Also, you don’t have to wait to see these two planets coming together. From now until Dec. 21, Jupiter and Saturn will get closer each night in the western horizon. The best time to see them is in the evening sky, mainly during the twilight.

Here in North Idaho, with high pressure over our region, you may get a chance to see these two planets, assuming the low clouds and fog do not form during the early evening.

Many scientists agree that life on Earth would likely not exist without Jupiter. Computer simulations show that Jupiter and also Saturn’s large gravitational fields have likely protected Earth and the other interior planets from many impacts from large, fast-moving objects in space.

Of course, Earth has seen its share of meteorite impacts, including the one that probably ended the reign of the dinosaurs about 65 million years ago. But, Jupiter and Saturn’s gravity, in theory, seems to have given us enough protection for life to thrive on Earth as too many impacts could have likely resulted in the loss of our planet’s atmosphere.

The intense gravity of Jupiter is believed to have directed some of the objects in space out of our solar system before getting close or having some kind of impact with Earth.

Comets that enter from outside our solar system would have collided with our planet more frequently without Jupiter standing in their way. Astronomers have also seen some of these comets that have crashed into the giant planet.

In 1994, the Comet Shoemaker-Levy 9 broke into smaller fragments and collided into Jupiter. In 2009, astronomers also observed a giant crash, likely caused from another comet, into the side of Jupiter.

In case you were wondering, Jupiter has the shortest day of all planets, only 9 hours and 55 minutes, and has at least 67 moons. Its Great Red Spot is a huge storm that has raged for at least 350 years and is so big that three of our Earths could fit inside.

Saturn has a day of 10 hours and 42 minutes and has 82 moons. Of course, Saturn is famous for its system of rings that surround the planet.

An article by Forbes says that these rings are made of 99 percent water-ice and scientists do not know from where they originated. However, the rings are nearing the end of their lifespan. It’s estimated that in about 300 million years, the infamous rings will be gone.

In terms of our local weather, conditions have turned drier than normal as high pressure has built into the western U.S. However, November was a good month for moisture as Cliff recorded 3.03 inches at his station. It was very close to the normal of 3.07 inches. As of the weekend, there is a chance of some moisture today could push our monthly total to near or slightly above the monthly average.

The normal snowfall for November is 8.7 inches and we picked up 6.2 inches. Although the figure is below average for this month, it’s far better than last year’s total of just 0.1 inches, a record-low snowfall for November. Thanks to the record snowfalls in October, our seasonal total is at 16.1 inches, which is still above normal.

As I mentioned last week, the middle of next month, during the new moon lunar phase, is our next best chance for additional snowfall across North Idaho. We also have a good chance of snow around New Year’s Day.

Christmas Day falls in the middle of the first quarter, so chances are lower for snow to fall on Dec. 25. Hopefully, there will be enough on the ground to give us another white Christmas across the Inland Northwest.

And, there’s always a chance that the skies will be clear enough on Dec. 21 to see the conjunction of Jupiter and Saturn.