Jupiter, the goliath planet of our solar system, is set to put on quite a show through the summer in the Butler sky.

Currently it’s high enough and certainly bright enough for great viewing. Unfortunately, though, because of where it is among the backdrop of stars in 2018 coupled with the very late start to stargazing this time of year it requires the loss of some sleep to observe it, unless you’re a perpetual night owl. By around 11 p.m. it’s high enough in the southeast sky and far enough from the horizon avoiding most of the blurring effect of Earth’s atmosphere.

There’s certainly no mistaking it since it’s overwhelmingly the brightest starlike object in that part of the sky. In fact the only other brighter starlike object is the planet Venus that sets below the western horizon shortly after evening twilight.

As you gaze upon its brilliance, Jupiter is just under 410 million miles away and has a diameter of 88,000 miles, more than 10 times the girth of the Earth. In fact, if Jupiter were hollow you could fill it with well over 1,000 Earths.

Jupiter will have some bright company in the southeast evening sky this coming Memorial Day weekend, the Earth’s moon. On Saturday evening, May 26, the waxing gibbous football shaped moon will be just above and a little to the right of Jupiter and on evening, Sunday, May 27, the moon will be just to the left of Jupiter and a little closer to being a full moon. You don’t want to miss this really tight celestial hug.

Of course the moon and Jupiter aren’t anywhere close to each other physically. The moon is around 245,000 miles from Earth around Memorial Day weekend and Jupiter’s more than another 408 million miles distant. Both celestial bodies though are nearly in the same line of sight.

The moon and all the major planets pretty much take the same path among the stars called the zodiac band. That’s because they’re all pretty much on the same mathematical plane. In other words, if you were to shrink down our solar system to the point where it could fit on your dining room table it would pretty much lie flat on it.

Jupiter takes 12 years to migrate eastward among the zodiac constellation as it makes an orbit around our sun band while the moon rips through it in just over 27 days as it orbits our Earth.

Earth’s moon isn’t Jupiter’s only company this week. Jupiter also has its own moons that circle the behemoth planet all the time. At last count Jupiter has well over 60 moons. Four of its largest moons can be seen on either side of the planet with a small telescope or even a decent pair of binoculars.

They look like stars. With a small telescope you should also be able to see at least some of the methane and ammonia cloud bands across Jupiter’s face. The number of moons you see and where they are with respect to Jupiter depend on where they are in the 2- to 17-day orbits around the big guy.

The moons pass behind Jupiter on a regular basis and are lost from our sight, and they also pass in front of Jupiter and get camouflaged against the planet’s clouds. If viewing conditions are right and your scope is big enough you can actually see little dots on the face of Jupiter that are the passing shadows of the moons.

A long time ago Galileo Galilei (1564-1642) also spotted Jupiter’s largest moons. They played a huge role in helping Galileo prove that the sun, and not Earth, is the center of our solar system. In fact, these four moons are referred to as “Galilean” moons.

Anyone who knows anything about science knows that Galileo is one of the greatest minds of the last 1,000 years. While he was not the inventor of the telescope, he was the first person on record that really studied the sky with his crude telescope. He was trying to convince the world that Copernicus, who lived before Galileo’s time, was correct in claiming that the Earth was just one of the planets circling the sun.

In addition to all of his astronomical feats he also made huge contributions to physics, such as the acceleration of objects.

In the early 1600s, Galileo trained his telescope on Jupiter and couldn’t help but notice four little “stars” whirling around the planet. His obvious conclusion was that these stars were actually satellites in orbit around Jupiter.

Opponents of the sun-centered theory of the solar system argued that if the Earth and the other planets circled around the sun they would fly off into the “ether” and would be lost forever.

Galileo countered this faulty reasoning by pointing out Jupiter and its moons and basically saying … hey, these satellites are circling this heavenly body and they’re not flying off. He actually expressed it a bit more eloquently, but that’s essentially what he said. If you ever get to Florence, Italy, you can see Galileo’s crude but historic telescope at the Florence Museum of History and Science.

Almost 410 years later, Galileo once again made new discoveries about Jupiter and its moons, only this time it was the Galileo space probe, now winding down after six years of exploration.

Before Galileo, the Pioneer and Voyager probes gathered pictures and data of the Jovian system. Because of these missions and other observations, we know a lot more about Jupiter’s moons, especially the four big Galilean moons.

The two outer moons, Callisto and Ganymede, are old crater-covered moons, about 4½ billion years young and not all that interesting except for the fact that Ganymede is the largest moon in our solar system, more than 3,400 miles in diameter.

On the other hand, Jupiter’s closest moons — Io and Europa — are anything but boring. Io, the closest moon, has more than 400 active sulfuric volcanoes and constant lava flows because of the tremendous tidal stress from its mother planet.

When the first color photographs of Io came back astronomers dubbed Io the “pizza planet” because it was various shades of orange and red from its volcanoes.

The second-closest moon, Europa, may have a slushy ocean under a thin layer of ice. Possible water geysers have even been spotted above the ice. Europa and Saturn’s moon Enceladus could be the only other places in the solar system besides Earth that has liquid water, and where there’s water, possibly life? Stay tuned.

In the attached diagram are the positions of Jupiter’s moons relative to the planet over the next seven nights. A wonderful free app produced by Sky and Telescope is simply called “Jupiter’s Moons.” Along with the app there also is a website to keep up with the whirling Galilean moons at www.skyandtelescope.com/observing/celestial-objects-to-watch/jupiters-moons-javascript-utility/.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis/St. Paul. He is the author of “Stars: a Month by Month Tour of the Constellations,” published by Adventure Publications and available at bookstores and at adventurepublications.net. Contact Mike Lynch at mikewlynch@comcast.net.