Catch an Awe-Inspiring Great Conjunction of Jupiter and Saturn on December 21st

Catch an Awe-Inspiring Great Conjunction of Jupiter and Saturn on December 21st

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Catch an Awe-Inspiring Great Conjunction of Jupiter and Saturn on December 21st

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By DAVID DICKINSON, Universe Today

Dozens of planetary conjunctions grace our skies every year, as two planets seem to pair up as seen from our Earthly vantage point. Many are speedy affairs, as fast-moving inner worlds such as Mercury and Venus lap the sky, visiting the Moon, planets and stars along the ecliptic.

What’s more unusual is to spy a pairing up of the two slowest moving naked eye outer planets, Jupiter and Saturn. That’s just what happens next Monday, as Jupiter meets Saturn on the December 21st solstice. The two worlds will appear to be just 6.1 arcminutes (’) apart at ~18:00 Universal Time (UT) (1:00 PM EST), 30 degrees east of the Sun.

Though the two largest planets in the solar system lap each other once a generation (roughly once every 20 years), this conjunction is especially close: in fact, it won’t be topped until March 15, 2080 (6.1’). You have to go all the way back to July 16, 1623, to find one closer (5.2’ apart), though that particular conjunction was much lower in the sky and much more difficult to spot, at just 13 degrees from the Sun.

The last easily visible pairing of Jupiter and Saturn topping this year’s conjunction was on the morning of March 5, 1226 AD.

Though the timing of its closest approach favours longitudes centered on Europe and Africa, you can see the two getting closer night-by-night worldwide this week, going into this weekend. In fact, Jupiter and Saturn will remain less than one angular degree apart (easily close enough to hide behind your pinky at arm’s length) until December 30th, and closer than 30’ (the angular diameter of a Full Moon) from December 17th to the 25th.

The two planets will almost seem to touch on the evening of the 21st, though in reality, the two gas giants are 883 million kilometres (548.7 million miles) apart. Jupiter shines at magnitude -2, while Saturn is just seven times fainter, at magnitude +0.6. The razor-thin waxing crescent Moon just misses occulting the pair by three degrees on the evening of Wednesday, December 16th. (photo-op!)

Be sure to crank up the magnification, as you’ll have the rare opportunity to fit both solar system gas giants in the same field of view. You’re looking at over 90% of the planetary mass of the entire Solar System, right in one convenient view. Jupiter is 33 arcseconds (”) across on the night of the conjunction, while Saturn is 36” (with rings) from tip-to-tip. Be sure to check out the respective retinue of moons for each as they slide by one another in the sky.

Looking back from the local vicinity of Saturn, you’d see Jupiter slide just 7’ past the Earth, with both just three degrees from the Sun.
17th-century astronomer Johannes Kepler placed great significance in the conjunctions of Jupiter and Saturn. Kepler was the last great astronomer who also subscribed in part to the archaic practice of astrology, and he scrutinized at length what he termed as the ‘great conjunctions,’ or repeating patterns of conjunctions of Jupiter and Saturn returning to the same astrological house every 60 years.

These ‘trines’ or triads of great conjunctions held great sway over Kepler’s thinking, leading him to suggest that the Star of Bethlehem was related to a close pairing of Jupiter and Saturn in 7 B.C. in Pisces the Fishes, a sign long associated with Judaism.

This year’s conjunction occurs on the border of the modern astronomical constellations of Sagittarius and Capricornus. With the conjunction falling just a few days before Christmas, expect the annual discussion of “what was the star of Bethlehem?” to come to the fore once again… though biblical and historical references to the actual event are so scant, we’ll probably never truly know for sure.

 

Looking Into the Far Future

Can Jupiter ever occult Saturn? Well, we looked at 20,000 years worth of conjunctions (it’s what we do for fun) and found 58 close (less than 10’ apart) conjunctions of Jupiter and Saturn over 200 centuries, with only 11 in the 2000 year span from 1000 AD to 3000 AD… but only 5 that are closer than the conjunction in 2020.

Close (less than 10′ apart) conjunctions of Jupiter vs. Saturn over the span of 2000 years, from 1000 AD to 3000 AD. Credit: Dave Dickinson

One especially intriguing event ‘may’ occur on (mark your calendars) June 21, 7541 AD, when Jupiter may actually occult (pass in front of) Saturn. This will certainly pose a bizarre spectacle, as the moons of the two intertwine, and Jupiter dons Saturn’s rings!
We say ‘may’ because the precise position of the planets over extremely long periods of time are subject to tiny gravitational perturbations from each other, and those minuscule effects do add up to a small amount of uncertainty when we look out over tens of thousands of years.

To be sure, there’s not much in terms of scientific value behind next Monday night’s conjunction, but the spectacle offers a wonderful opportunity to show off the two worlds at the eyepiece, while we contemplate the clockwork universe and how it provides us with such rare views across time and space.

Fraser Cain, a Comox Valley native, is the publisher and founder of Universe Today, one of the world’s leading websites on outer space. It is headquartered in the Comox Valley.

 

 

 

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Fraser Cain: from Hornby Island to outer space

Fraser Cain: from Hornby Island to outer space

PHOTO: Fraser Cain launched Universe Today in 1999. Photos courtesy of Robert Cain and Universe Today.

 

Fraser Cain was raised on Hornby Island, but his mind was always on another planet. Most of the time, Cain led the life of a normal teenager. He played video games and fooled around on the two-ferry, two-hour bus ride to school in Courtenay.

But whenever he could, Cain dreamed about the stars, the planets, the universe. He loved Star Trek. Read science fiction books. He watched NASA rocket launches on television.

He devoured information about space like a black hole sucking up everything within its immense gravitational grasp.

Today, Cain is recognized world-wide as an authority on space and astronomy. His website, Universe Today, is one of the biggest and most popular sources of news and information about space on the Internet.

The “Astronomy Cast,” a podcast with Fraser Cain and Dr. Pamela Gray

Universe Today had more than 48 million readers in 2016, and 140,000 people follow the website on a daily basis, and they do it religiously. Space buffs are serious about their interest.

He also hosts a weekly podcast on the website Astronomy Cast with renowned astronomer Dr. Pamela Gray, who runs CosmoQuest, a virtual research facility.

His company has published two books on skywatching, and he has an asteroid named after him.

And he does all of this from his home on the Puntledge River in Courtenay.

The early years

Cain refers to his father and mother as “big space nerds.” His dad has been a sci-fi fan since he was able to read.

“I grew up in Vancouver,” father Bob Cain said. “My brother and I built our first telescope before we were teenagers and spent many nights examining the sky.”

To encourage his fascination with outer space, Cain remembers his parents taking him outside to view the night sky, which is considerably darker than in metro Comox Valley, where they taught him about the constellations.

“In the summer, (we) would take sleeping bags out to Helliwell Park where we would watch meteor showers,” his father said.

And, of course, science fiction books and movies were the standard fare around his house. His mother, Josephine, took him to the first showing of the original Star Trek movie. He got his first serious telescope at age 14.

Two of Fraser’s astronomy columns in The Breezeway, circa 1989.

So it was natural that the family would gather around the TV on April 12, 1981 to watch the first space shuttle launch, something they continued to do for every subsequent shuttle mission.

When Cain arrived at G. P. Vanier High School in 1986, he starting writing astronomy columns for the now-defunct student newspaper, The Breezeway. He recalls they were quite well read.

Educator Brent Reid, who taught journalism and oversaw production of the Breezeway, remembers Cain as “a real go-getter.” He graduated in 1989.

Developing his popular website

Turning this passion for space and astronomy into a career didn’t really begin until after Cain enrolled at the University of British Columbia to study engineering.

Well, after he dropped out, to be precise.

Cain left UBC to write books for role-playing games, and co-founded a company called Absolute Software, which has since gone public on the Toronto Stock Exchange. At age 19, he helped invent software that enabled people locate and recover stolen computers, which you can still purchase at any Apple store.

Cain then joined a web design company, Communicate.com, where he helped clients design and construct their websites.

While there he hired a young entrepreneur named Stewart Butterfield, who went on to found Flickr.

Cain calls that, “one of my better hires.”

But Cain didn’t have any experience running a website, so he decided to start one of his own in order to better understand his client’s’ issues and to learn how to help them.

Fraser at age 14 with his new telescope and the astronomy club on Hornby Island.

He briefly considered a website focused on gaming, but of course he settled on space and astronomy. And that’s when he learned what he wanted to do with his life.

Universe Today was launched in 1999 and became so successful that Cain was able to quit his day job in 2003 and make space journalism his full-time career.

Cain has succeeded in a crowded field because he’s one of the few space journalists who do it well. He focuses on stories “way off the beaten path,” the topics that other space journalists aren’t covering.

Cain has written many of the 15,000 articles in the Universe Today archive, but the website also publishes the work of more than a dozen full-time and part-time other space journalists.

His senior editor lives in the U.S. His video editor lives in Prague.

Back to the Comox Valley

“It doesn’t matter where I work from,” Cain said. “During the course of the day, I talk to people all over the planet, some in space.”

Cain still travels to astronomy conferences, but he prefers to work from home, where he can help raise his two children.

He’s completed his university computer science degree now, and found the time to start up a new software company, Keyword Strategy.

The name, Fraser Cain, has become a personal brand within the universe of space journalism over the last 10 years. His name and face are now widely recognized.

But the Hornby Island boy hasn’t forgotten his roots. Not long ago, he took his sci-fi-loving dad to see the second last space shuttle launch at NASA’s Kennedy Space Center in Cape Canaveral, Florida.

In a personal article on social media, Cain wrote, “I hate to sound trite, but I’m a living example that you can succeed if you follow your dreams. You know that stuff you loved as a kid, but then decided to grow up and get a real job? That can turn into a real job, if you’re willing to believe in yourself and put in the work.”