Jupiter, Venus get cozy with each other

This weekend we say goodbye to spring and hello to summer. We also say hello to the days getting shorter again, but no need to expound on that.

The Summer Solstice is this Sunday at 11:39 a.m. That’s when the sun will reach its highest northern position in our sky.

This happens because of the 23.5 degree tilt of the Earth’s axis with respect to the orbital plane around the sun, causing the sun’s rays to favor the northern horizon this time of year.

Six months from now, around the time of the Winter Solstice, the southern hemisphere gets the majority of the sun’s light.

Because of the sun’s far northern position in the sky, it will be the longest day of the year as the sun makes a long lazy arc from the northeast horizon at sunrise to the northwest horizon at sunset.

It will reach a maximum midday height of more than 72 degrees above the southern horizon around Butler.

The early evening summer skies will be dominated by the spectacular conjunction, or what I call a celestial hugging, between the very bright planets Jupiter and Venus for the next several weeks.

Without a doubt they are the brightest starlike objects in the evening sky, popping out in the western sky even before the end of evening twilight. If you’ve been watching the skies over the last month or so you’ve probably noticed how they’ve been getting closer and closer to each other.

At the start of this week, Jupiter and Venus are separated by five degrees, less than your fist width at arm’s length, but by the evening of June 30 they’ll be less than a half a degree apart, about the width of a full moon.

From now until then, check out Venus and Jupiter every evening, weather permitting. The shrinking separation between the two from night to night will really be obvious. It’s also a great teaching tool if you watch it with your children.

Venus and Jupiter were actually this close last August, but you had to get out in the super early morning twilight to see it. This time the two shiners are visible in “prime time.”

I think it’s really cool that one of your fingers held at arm’s length will be able to cover up two planets, including the largest planet of our solar system.

Jupiter, with its 88,000 mile-wide diameter, is so big that if it were hollow you could fill it up with more than 1,000 Earths.

All of the planets in our solar system orbit the sun at their own respective paces in nearly the same plane, so these kinds of conjunctions between planets are pretty common.

However, conjunctions are not always this tight of a celestial hug between the two brightest planets we can see from Earth.

Venus, named after the goddess of love, and Jupiter, named after the king of the Greek and Roman gods, meet each other in a close conjunction about every 13 months, some encounters closer than others.

There will actually be closer conjunctions of Venus and Jupiter in late August 2016 and in mid-November 2017, but those conjunctions will be low in the sky and will get lost in the very bright twilight.

A super close Venus-Jupiter celestial hugging that’s easy to see won’t happen again until well after 2020.

Even though Venus and Jupiter look like they are touching, that’s certainly not the case. They’re actually separated by hundreds of millions of miles.

Venus is much brighter than Jupiter because it’s so much closer to Earth at less than 45 million miles away. Meanwhile Jupiter is more than 550 million miles distant. The very reflective cloud cover on Venus is also beaming a lot of sunlight our way.

Both planets are nice to see through even a small telescope, but for different reasons.

With Jupiter you can easily see up to four of its largest moons; Io, Europa, Callisto and Ganymede. They resemble tiny stars on either side of Jupiter. As they orbit around the big guy of the solar system in periods of 2 to 17 days you always see different arrangements of the moons from night to night.

Some nights you won’t see all of them because one or more might be behind or in front of Jupiter. With your scope you might also see some of Jupiter’s brighter cloud bands made of methane, ammonia and other gases.

As soon as it’s dark enough, turn your scope to Jupiter while it’s still high above the horizon. If you wait until it gets close to the horizon it will have a much more fuzzy look because of the blurring effect of Earth’s atmosphere.

Venus sports a much different look. Because of the solid cloud cover made of acid rain there’s no way you’ll see the surface, but you will see that Venus looks like a tiny half moon.

Because Venus’ orbit lies inside the Earth’s orbit around the sun, both Venus and Mercury go through phases just like our moon. It’s best to observe Venus in early twilight so the glare doesn’t overwhelm what you see.

From at least June 28 to about July 2 it will be possible to see both planets in the same field of view. That’s something you don’t see often.

Enjoy the great celestial hugging of 2015.

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