Fourth of July Sky: Jupiter and Saturn

January 29, 2019
Jupiter and Saturn

Independence Day (U.S.) is the evening when most Americans are watching the sky. While you wait for fireworks, gaze at Jupiter, the Moon, and Saturn!

What’s in the Sky the 4th of July

As twilight deepens around 9:30 PM on the 4th, the very brightest “star” is the planet Jupiter, to the left of where the Sun set. 

At the same time, far to the left of the Moon hover two stars of equal brightness. The orange one is the famous Scorpius star Antares. The other is Saturn.  If you’re in doubt, point any binoculars its way and it’ll look a bit uneven, not quite a starlike dot. A telescope using at least 30x lets you observe those gorgeous rings.

Note that the exact conjunction of Jupiter and the Moon takes place on the 1st of July; Saturn and the Moon are in conjunction on the 6th of July, so you’ll watch the Moon pass close to Jupiter and then the Moon over the week. 

Jupiter and Saturn and the Great Conjunction

This meeting of Jupiter and Saturn is a great preview of their meeting in 2020.

These two giant worlds will draw closer the next few years.  They will meet on the first day of winter in 2020. 

This solstice conjunction will be the most spectacular meeting of planets in our lives.  The two will be so close to each other, they’ll merge into a single ball, at least for those with marginal vision. Through a telescope, they’ll fit into the same field of view, separated by just one sixth the width of the Moon.

We’ve never seen it in our lives.  (In case you wonder if Jupiter can ever actually eclipse Saturn by passing directly in front of it, yes– it will next happen in 7541.)

This century, these meetings of Jupiter and Saturn, called “great conjunctions,” happen in years divisible by 20.  It last occurred in 2000, in the constellation Taurus.

  • Much has been made of the fact that seven presidents who were elected during or near a year of a great conjunction died in office.  Want more astro-coincidences?
  • Earth’s radius is 3,960 miles, while the Moon spans 1,080 miles from its surface to its center. Their combined radii are 5,040 miles. Well, this happens to be the number of minutes in a week. It’s also equal to 1 x 2 x 3 x 4 x 5 x 6 x 7. Which, incidentally, also equals 7 x 8 x 9 x 10.
  • More? Well, the orbital period or year of Uranus, Neptune, and Pluto are 30,000 days, 60,000 days, and 90,000 days. Okay, this was after rounding off, but still…

You can keep going with numerical stuff like this, or finding anagrams of body parts (Earth’s letters spell “heart” while Mars is “Arms”) or ponder why every other planet contains the letter “U.”  

The biggest take-away from all this? Maybe that it’s important to know when to stop.

Enjoy the 4th of July night sky, and let’s hope for a clear night!

About This Blog

Welcome to “This Week’s Amazing Sky,” the Almanac’s hub for everything stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe