‘Christmas Star:’ Jupiter and Saturn combine for the rare Great Conjunction

ORLANDO, Fla. – It is a celestial event hundreds of years in progress. Conjunctions are common and occur when any object from our perspective approaches each other in space. The Great Conjunction is rare.

The Great Conjunction happens when Jupiter and Saturn get very close to each other from our perspective. However, not all great conjunctions are created equal and this is what makes what happens on the winter solstice so rare and special.

“Each Great Conjunction has different angular separations, or the distances between the two planets can vary slightly depending on how everything is aligned,” said Seth Mayo, astronomy curator at the Daytona Beach Museum of Arts and Sciences.

The last time the two planets were so close to each other, from the point of view of the Earth, was in 1623. “The problem with this Great Conjunction is that it occurred very close to near sunset, so the glare of the Sun probably hid the pair of planets. “The last time these planets were observed so close was in 1226,” Mayo said.

Because the planets will be so close together for Christmas, some christened them the “Christmas Star.”

On December 21, the two gas giants will be separated by only one degree. At first glance, it will probably appear as two distinct points, rather than a “star,” but it depends on the view and weather conditions.

If you have a telescope, both planets will appear in the same field of view.

Also in this field of vision will reside the larger moons of the two bodies. You will need a telescope or binoculars to see the moons.

Beyond December 21, Jupiter and Saturn will begin to move away from each other. This trend will continue for the next ten years before the two giants begin to approach each other again during the 2030s. This will set the next Great Conjunction in 2040, though it won’t be as bright as 2020.

The planets will not be so close again until 2080. In an extremely rare way, Jupiter completely covers Saturn. This will not happen again until 7541.

The Great Conjunction occurs because Jupiter has the inner track as it orbits the Sun in our solar system. Since Jupiter’s orbit is smaller than Saturn’s, Jupiter moves around the sun faster and reaches the ringed planet. Think of it as a NASCAR race with the inner field the Sun. The car that has the inner lane moves on the route faster than a car on the outside.

“On very rare occasions, these large conjunctions between Jupiter and Saturn can occur several times a year, known as triple conjunctions, because the Earth is advancing these planets with their orbit much faster,” Mayo said. . “That won’t happen again until the 2238-2239 time period, so we have a little bit left to do.”

The last time a triple conjunction occurred was in 1981.

The Seminole State College Planetarium Emil Buehler Perpetual Trust organizes a “Great Virtual Star Celebration of the Jupiter / Saturn Conjunction. It’s a free event for everyone.

There are events on December 19th and 21st.

You can learn more at seminolestate.edu/planet.

Details:

When: December 21, 2020

On: Southwestern sky about 30 min. after sunset

Notes: The planets will gradually descend into the sky as the afternoon progresses, therefore, the sooner the better.

You don’t need a telescope or binoculars to see, but they will enhance the visual experience.

You’ll notice these two bright spots, Jupiter and Saturn getting closer to each other every night until December 21st.