What IS this "Christmas Star" appearing in the sky?

[Ron Schmit]

Look southwest at 5:00 pm to see a rare astronomical treat: a Jupiter/ Saturn conjunction. Despite their immensity, they only appear as bright stars in our sky. The origin of the word “planet” misses most of our modern definition. Prior to invention of the telescope, the Latin word “planeta” simply meant ‘wandering star.’ There were five of them that moved about relative to the other stars. So intriguing, the ancients named them after their Gods: Mercury, Venus, Mars, Saturn, Jupiter.

We now know that they are big balls of gas and rock, like the Earth, each with their own orbit about the Sun. Jupiter takes 12 years to orbit, while Saturn takes 29. Now a clock’s hands also spin at different rates, but align every 65 minutes. Something similar occurs with the planets. Approximately every 20 years, Jupiter catches up with Saturn in the sky.

This is the event we are watching play out right now, coming to just 0.1 degrees of each other on December 21. So close, they will appear as one star in the sky. A similar event has been suggested as an explanation for the Star of Bethlehem. This is why social media is flooded with news of “The Christmas Star” reappearing in our sky.

Perhaps something unexplainable took place back at the birth of Jesus, but nothing was sighted by others also watching for heavenly signs. For perspective, we can look at the Bible:

“After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem and asked, ‘Where is the one who has been born king of the Jews? We saw his star in the east and have come to worship him.’ ” ~ Matthew 2: 1 – 2

Often, our English translation removes an important essence from a word. In the Greek translation of Matthew 2:1, east is referred to as anatoli which means the direction east, but the second reference to east is anatolay which refers to the heliacal rising. This occurs when a star rises in the east just before the Sun. Before mechanical clocks, the sky was our timekeeper. For example, farmers in ancient Egypt knew it was time to plant the first day they saw the star Sirius rise before the Sun (its heliacal rising.) This heralded the annual flooding of the Nile, providing ample water for irrigation.

So what was “his” star? In Jewish astrology, Jupiter was considered the King Star, and Saturn, the Star of the Messiah. The two appearing together in the heliacal rising was enough to spur the magi westward to Jerusalem. Why west? Because the stars appeared together in the constellation Pisces, which represented Judea, they went to Jerusalem where Herod’s scholars would tell them:

"But you, Bethlehem Ephrathah, though you are small among the clans of Judah, out of you will come for me one who will be ruler over Israel” ~ Micah 5:2

If getting to Jerusalem took 6 months, by then the Messiah star would now appear to the southwest, over Bethlehem:

”After they had heard the king, they went on their way, and the star they had seen in the east went ahead of them until it stopped over the place where the child was.“ Matthew 2: 9

Lovely to see this conjunction happening at Christmas time. Such a great opportunity to encourage people to go out and behold the wonders of the night sky. Please, grasp this opportunity to take some people out and show them this conjunction, and while you're out there, spin around to the east and show them the Winter Circle coming back to our sky. Wonders, indeed.

[Ron Schmit]

Here's a set of Frequently Asked Questions for the Jupiter/Saturn Conjunction:

Where do I look to see this event?
Look off to the southwest (where the sun sets) starting about 5:00 PM, local time. You should see a bright star about 15 degrees above the horizon (here in Minnesota.) That's about the size of your fist at arm's length. That bright star is Jupiter! Just above and to the left (a little fainter) will be Saturn.

Is it only visible on Monday, December 21?
It will be closest on the 21st, but don't wait!! Go out and see it tonight and every night for the next week. Since it happens low on the horizon, there is a chance clouds could obscure your view. Don't forget to look during the rest of the week, as well. They will start to move apart slowly over the next week.

Will it be up all night?
No! The pair will set about 7:00 pm. Make sure to go out and see them before 6:30 pm, before they get too low.

Do I need a telescope to see them?
No, you can see this conjunction with the naked eye. Of course, if you have binoculars or even a small telescope take a look! You may be able to see Jupiter's moons (they will look like tiny stars, lined up with the planet) or you might glimpse Saturn's rings!

Where is the best place to see it?
Anywhere that has a clear horizon to the southwest. Of course, getting away from city lights will help. A darker sky will make them appear brighter.

Are they going to collide?
Not a chance! Saturn is a billion miles away and twice as far from the Sun as Jupiter. This is just a line of sight effect.

Has this happened before?
Jupiter takes 12 years to go around the Sun. Saturn takes 29, so every 20 years, Jupiter passes Saturn in the sky. Imagine the hands of a clock; every 65 minutes, the minute hand passes the hour hand. Our solar system spins about like a great clock.

I've heard it happened 400 years ago, I've heard 800... Now you're saying it happens every 20 years! Which is it??
Jupiter passes Saturn every 20 years, but they've not been THIS close since 1623. However, back then, it happened while the two were VERY close to the Sun in the sky, and it would have been nearly impossible to see. Back in 1226, they were this close AND it was easy to see.

Will they become exceptionally bright that night?
No brighter than any other time. They are simply appearing closer together.

Are astronomers learning new things from this special event?
Not at all! Events like this occur all the time and don't have a lot of scientific benefit, but astronomy is NOT just scientific, it's also cultural. Peoples throughout history have marveled at the wonders of the sky. They fascinate and intrigue us: “For everyone, as I think, must see that astronomy compels the soul to look upwards and leads us from this world to another." ~ Plato

Why is this happening on the Winter Solstice?
That is just a happy coincidence. There is a 1 in 365 chance that it will happen on a certain day of the year. Those aren't really long odds, are they? No, the coincidence of the solstice and the conjunction are just that. The Winter Solstice is the day the Sun reaches its lowest point in the sky, for the northern hemisphere. Every day since the first day of summer (the Summer Solstice) the Sun has been getting lower and lower in the sky making the days shorter. On the 21st our Sun ceases its retreat and heads back into our sky and our days get longer once again. That's totally an Earth/Sun thing: the result of Earth's axis being tipped 23.5 degrees. This changes the position of the Sun in our sky, thus producing our seasons.

Why do they call it a star, when it's two planets?
The word planet comes from the Latin word "planeta" which means wandering star. Back then, the planeta were five stars that moved about in strange patterns, relative to the background stars of the sky.

I heard Dr. Kaufmanis talk about the “Christmas Star.”
Not a question, but we hear that a lot, here in Gopher Country! Dr. Kaufmanis gave this lecture over 1000 times during his career. Though he passed away in the 2003, you can still hear the words of this lovely Latvian gent: the University of Minnesota has an audio archive of his presentation, that you can listen to here: https://sites.google.com/site/astrologi ... bethlehem/