Commentary: The greatest show in the Solar System | Chaska Opinion

Ask a group of people to name the most amazing thing they have seen in the daytime or nighttime sky and you may get answers like: the total solar eclipse of August 2017, Venus’ solar transit in 2012, the amazing appearance of Comet Hale-Bopp in 1997, the intense supernova of 1987, the stunning 1966 Leonid meteor storm, or seeing Sputnik 1, the first artificial satellite, at the dawn of the Space Age in 1957.

These are just a few examples of exceptional naked eye sky sights. How many people however, can say they have seen all five naked eye planets simultaneously and displayed in their correct order from Mercury to Saturn?

Opportunities to see Mercury, Venus, Mars, Jupiter and Saturn arrayed so they can be observed together, in consecutive order, are rare. Some people saw the most recent “planet parade” (as these events are now called) in late December 2004, but it is certain few (if any) can say they saw the previous example – in late November 1921!

Now, everyone has a chance to see one of these remarkable planet gatherings. This event will begin on June 18 and continue through June 27. The only things you will need to enjoy this planetary pageant are your eyes, an observing site with an unobstructed view of the eastern and southern horizon and a willingness to look at 4:45. I have!

How frequently do the five naked eye planets appear in their natural order? Events of this kind happen within four to five years before or after Jupiter and Saturn appear closest. Meetings of the solar system’s two giant planets are known as “Great Conjunctions”; they happen at 20-year intervals (the last example occurred on Dec. 21, 2020). If all five planets appear in consecutive order prior to the date of a Great Conjunction, the planets will be visible after sunset. When the five-planet parade happens after a great conjunction occurs, the event will be seen before sunrise (this is the situation for the 2022 display).

The accompanying illustration provides a panoramic view of this month’s planet parade. Prime time for observation is 45 minutes before sunrise during this year’s week-and-a-half window of opportunity. The illustration shows the direction to look for each of the planets above the horizon – from east-northeast, to just a few degrees shy of due south. Each planet’s angular height above the horizon is also indicated. Remember that 10 degrees is equal to the width of a clenched fist at arm’s length. Mercury and Venus will appear low (5 degrees and 10 degrees above the horizon respectively); Mars, Jupiter and Saturn will appear three times higher – close to 30 degrees above the horizon.

The apparent brightness of the planets is also shown. Jupiter and Venus are always dazzling; Mercury, Mars and Saturn will be noticeably dimmer, but still easily visible with unaided eyes. The brightest stars in the field of view occupied by the planets have also been added, together with their respective astronomical names. None of these stars will be easily seen during morning twilight; binoculars will reveal their presence, however. If you like a challenge, scan the sky just above Venus for the famous “Pleiades” star cluster. Both Venus and the star cluster will fit within the field of view provided by binoculars from June 23 to June 27.

The moon will figure in the June 2022 planet parade also, appearing beside each planet, making planet identification a cinch! Notice the slender crescent moon beside Venus on June 26; it’s a sight that always inspires “oohs and ahs!” The following morning, an even more slender moon will appear next to Mercury. Use that slim moon to zero in on this elusive planet, suspended in the glare of the approaching sunrise.

While taking in the illustration of the June 2022 planet parade, you probably noticed that an arc can be drawn connecting all five planets. It is tempting to imagine that this arc represents a line. Indeed, many writers have described this and other celestial spectacles like this one as an “alignment.” We’ve all seen pictures of the solar system that show the planets arrayed like beads on a string, extended outward from the sun. In truth, this kind of solar system geometry does not exist!

If we could observe the planets from a place well above our solar system, the planet “alignment” we see on Earth disappears. The accompanying illustration reveals a completely different view of this month’s planet parade. From it, we discover that connecting the five naked eye planets forms a definite zig-zag pattern. When viewed this way, the earthly “alignment” instantly vanishes. Thus, our earthbound view of the planets gives rise to the “illusion” of a planetary alignment. Thus, using the word “grouping” to describe what we are seeing, makes more sense – and it is less misleading.

If by some chance you miss seeing the June 2022 planet parade, how long will you have to wait for the next opportunity to observe a display like it? Although many current sources cite the fall 2040 array, that planet group will be too close to the Sun to be seen by residents of Earth’s Northern Hemisphere.

For us, the next chance will take place in late October and early November 2060. Like this year’s display, it will be visible during morning twilight. If you would prefer to observe a five-planet gathering in the evening, you will have to wait a little longer. The next example will occur at the end of April and the beginning of May 2100.

Given the long wait for either of these two options, this year’s opportunity certainly rises to the level of a “must see” event. For many of us, it will likely be “The greatest show in the Solar System!”

Rod Nerdahl has taught and written about astronomy and space exploration for nearly 50 years. He worked as one of the astronomy educators at the Minneapolis Planetarium for 27 years. He also prepared all of the astronomical material published in the Minnesota Weatherguide Calendars for 28 years. He and his wife Peggy live in Chaska.

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