Skywatch for the week of September 13, 2021
Mon Sep 13, 2021 ELEVEN DAYS MISSING!
Did you know that here in America, there was no September 13th in the year 1752? There wasn’t a 12th either, or an 11th, or a 3rd through the 10th! It happened when the Gregorian calendar replaced the Julian calendar. The Julian calendar, established by Julius Caesar seventeen hundred years earlier, was inaccurate; it was behind by ten days when Pope Gregory introduced the Gregorian calendar to Catholic countries in 1582.
But England and its Protestant colonies ignored the papal edict, and kept using the old Julian calendar, until 1752, when, in order to fix the calendar, eleven days had to be chopped out. Riots broke out in London as landlords charged their renters a full month’s rent, even though the month was just 19 days long. “Give us back our eleven days!” they shouted. But in America, Ben Franklin counseled his readers not to “regret.. the loss of so much time,” but to give thanks that one might “lie down in Peace on the second of the month and not… awake till the morning of the 14th.”
Tue Sep 14, 2021 MARDUK BRINGS ORDER OUT OF CHAOS
A very old story about how the Universe got its start comes from ancient Babylonia. It began with the watery chaos, known as Mammu. Out of Mammu came a monstrous dragon named Tiamat. Tiamat then spawned the Babylonian gods, but in time she came to hate them and decided to destroy them. But her grandson Marduk fought and defeated her. He used her body to serve as a framework for the cosmos.
Half of her became the sky, where Marduk set the god Anu; the other half was made into the foundations of the earth, and Marduk made Ea its god. Marduk became the principle sky god, like Zeus in ancient Greece, and gave other gods responsibilities for the southern and northern skies and their constellations, while Marduk reserved the planets and stars of the zodiac for himself. And old Tiamat? You can see a vestige of her in the constellation Draco the Dragon, winding between the Big and Little Dippers tonight.
Wed Sep 15, 2021 HYPERION
On September 19, 1848, father and son astronomers William and George Bond discovered Saturn’s oddly-shaped moon, Hyperion. To the Bonds, it was just a little point of light that changed position as it orbited the ringed planet. But thanks to the Cassini spacecraft, we see it as another world.
Named for the mythical Greek god of observation, Hyperion is a rugged moon over 200 miles in diameter; and ordinarily such a large object should be round, but Hyperion is a rather beat-up looking object, covered with craters, and very irregular in shape, looking like an old meatball, or perhaps a lufa sponge. Its composition is mostly water ice, with some rock and dust added for texture. Hyperion tumbles erratically as it orbits Saturn, probably owing to its irregular shape and the gravitational influence of Saturn’s biggest moon Titan. This evening you can find Saturn between the moon and the planet Jupiter in the southern sky, but Hyperion is a little too small to see without a good telescope.
Thu Sep 16, 2021 WAXING GIBBOUS MOON, SATURN AND JUPITER
At sunset tonight, you’ll find the moon well-placed in the southern sky. Actually, you can see the moon long before sunset, a waxing gibbous moon, appearing as a pale egg-shaped object in the blue afternoon sky. Anyway, as darkness sets in, you should see a couple of bright stars nearby it. There’s a very bright one, just to the left, or east of the moon. It’s actually the planet Jupiter. Jupiter is very bright, but there’s another, even brighter evening star, well off to the west, above the sunset, and as you’ve guessed, it’s another planet, brilliant Venus.
But there’s still one more planet in our evening sky tonight, and it’s very close to the moon – well, okay, it’s really hundreds of millions of miles beyond the moon, but because our depth perception doesn’t work at those big distances, it will seem to be parked right over the moon. It’s dimmer than Jupiter, but it has a slight yellow tint. Find it, and you’ll have found Saturn, among the stars of Capricornus, along with the moon and Jupiter.
Fri Sep 17, 2021 OPEN HOUSE/STEAM TALK
This year we will start a new series of free lectures at IRSC’s Hallstrom Planetarium on the main Fort Pierce campus. The 45-minute talks will be on select Saturdays at 6 pm, and will be followed by a live star show in the planetarium theater. And then, as weather permits, we’ll view the sky through telescopes, courtesy of the Treasure Coast Astronomical Society and our student club, Hallstrom Astronomical Society.
The Saturday STEAM - Science, Technology, Engineering, Arts (that is, Humanities) and Math - Talks will feature members of Indian River State College’s faculty and staff discussing topics in their areas of expertise. I will be giving the first talk this Saturday, September 18, with “A Year Full of Stars,” in which I’ll share with you all the wonderful sky events coming up in the next 12 months, including two lunar eclipses scheduled for November and May. See you at the Planetarium at 6 pm tomorrow. No tickets needed, it’s free!