Planets align for extraordinary ‘Christmas star’ solstice show

Tonight marks a spectacular event, an event in our solar system so rare that it can take decades to get a good view.

Jupiter and Saturn will appear closer to each other than they have been in hundreds of years, which is also the winter solstice.

So-called ‘conjunctions’, where objects appear very close to each other in the sky, are not uncommon, but this is special, astronomers have said.

CIT Blackrock Castle Observatory (BCO) education and outreach officer Frances McCarthy told the Irish Examiner that the event would be a delight for those who gaze at the sky in awe.

McCarthy said the science behind the event begins when the planets rotate around the sun, the farthest planets rotate more slowly, and the Earth rotates within a year. Jupiter takes 12 years and Saturn 29.5 years.

Skywatchers, a once-in-a-lifetime gift awaits you! Jupiter and Saturn are doing a planetary dance that will result in the Great Conjunction on December 21, just after sunset. Discover:

🤩 When and where to look
📷 How to photograph the conjunction

Visit: https://t.co/SdQSLex2Ex pic.twitter.com/DkaB5XyO9B

– NASA (@NASA) December 20, 2020

“So Jupiter is like a runner on one track, with Saturn on the next track, which is a larger orbit, and the planet is going a little bit slower,” he said.

“Jupiter will go around the track about two times and a bit, while Saturn will go around one lap. At the same time, Earth is circling on an inner track, circling 12 times for each time Jupiter rotates.

“From our perspective, we are looking across the track and we see two riders as we look in one direction: one is closer to us. [Jupiter], and one is much further [Saturn] – but we are looking in the same direction to see them.

“The sun is a bit in the way, since they are on the other side of the sun from us, so we can see them right at sunset.” They line up from our perspective roughly every 20 years, McCarthy said.

“The last time was in May 2000, but at that time Jupiter and Saturn were also on the opposite side of the solar system, so the sun was really in the way and it was very difficult to see. In 1980 and 1981, they lined up several times, but not as close as they are now, “he said.

Monday is an exceptional event for two reasons: We can see it and they are very close, according to Ms. McCarthy.

“To consider how close, we measure the position in the sky in degrees. If two things are one degree apart, they are about twice the width of the full moon. These will be separated by much less than a degree: one-tenth of a degree.

“When we talk about the ‘closest’ conjunction, we mean how close they seem to each other in the sky. They are still physically far apart.

This is one of the closest of all time, in the top 10 between 0 AD and 3000 AD But this happens regularly and is of no other importance unless you plan to be like NASA and send a space probe to visit a lot of planets

“So it should go when the planets are aligned, which NASA did with the Voyager Missions in the 1970s, using the 175-year alignment of the outer planets.”

Unfortunately, Astronomy Ireland predicts that tonight’s weather will ruin the view of the conjunction for many in Ireland.

For those who have a clear view, it is recommended to look to the southwest after sunset.

Alternatively, check out the live stream below from CosmoSapiens.