Skywatch for the week of October 10, 2022
Mon Oct 10, 2022 OCTOBER’S FULL MOON
The moon, just past full, is often called the Hunter’s Moon, because hunters in colonial America found its light useful when pursuing their own dinner in the dark. This is also the Sioux Indians’ Moon of Falling Leaves; the Big Wind Moon of the Zuni tribes; or the Cheyenne’s Moon When the Water Begins to Freeze on the edge of the Stream - must be getting cold up north. The Ponca Indians, in observance of the time when food is harvested for the winter, call this the Moon When They Store Food in Caches, while the Kiowa simply call it the Ten Colds Moon, a harbinger of the freezing weather that follows. October’s full moon was also called the blood moon in medieval England, a reference to the reddish coloring often displayed by the rising full moon of October.
Tue Oct 11, 2022 OLBERS AND HIS PARADOX
Heinrich Wilhelm Olbers, who discovered the asteroids Pallas and Vesta a couple of hundred years ago, was born on October 11, 1758. He is best known for what’s called Olber’s Paradox. Olbers asked a simple question: "Why is the sky dark at night?" Now that seems a bit silly - after all, the sky is dark at night because the earth rotates into its own shadow, what we call night. ”I know that,” he said. “But if the universe is infinite in size, then that means there's an infinite number of stars out there. So no matter where you look, you'll eventually find a star - the sky should be ablaze with light! But it's not.” This suggests that the Universe is perhaps not infinite, and that there was a definitive point in time in which everything began, and also that our Universe is expanding!
Wed Oct 12, 2022 MAGELLAN’S END
On October 12th, 1994, the Magellan spacecraft sent its final radio signal to Earth. The next day, NASA-JPL ordered Magellan, its fuel spent after four years in orbit about the planet Venus, to plunge into the Venusian atmosphere. Through the cloud-piercing radar of the Magellan spacecraft, we were able to “see” our sister planet’s mountains and its lowland rolling plains, as well as pancake-like volcanoes and great circular features called coronae, which were created by rising magma currents that periodically warp and destroy the crust. If you want to see Venus tonight, you’re out of luck, because its orbit has carried it over to the far side of the sun, and will be directly behind it on October 22nd. But it will reappear in our evening skies at the end of this year.
Thu Oct 13, 2022 INDIAN SUMMER, THE SEVEN SISTERS
The old gibbous moon appears over in the east late this evening, between the planet Mars and a tiny star cluster known as the Pleaides. To the Seneca Indians, the Pleiades were seven dancing maidens. At this time of year, the weather often turns pleasant, a respite from the first cold air of autumn. The Seneca tell of a village long ago where the people forgot to get ready for the cold times; when those first frosts appeared, they called out to the Great Spirit to aid them. Mannito granted them their wish: for ten days summer returned; then the thankful people prepared for winter. But there were seven dancing sisters, who paid no heed. Faster and faster they danced, until the West Wind took them in his arms and carried them up into the sky, where they became stars – the Seven Sisters we see tonight to the west of the moon.
Fri Oct 14, 2022 HOW TO SEE A BLACK HOLE
In the autumn evening sky, there are three bright stars high overhead which are called the Summer Triangle. In the middle of this triangle there is a great mystery - something which is invisible to the eye - that enigmatic phenomenon known as a black hole. It is called Cygnus X-1, and we can't see it directly because its gravity field is so intense that light can't escape it. But we know that it is there, because we've discovered an incredible amount of x-rays pouring out of this part of the sky. Cygnus X-1 is part of a binary star system. Gas from its companion, a massive blue giant, is being pulled from it to feed the accretion disc surrounding the hole; it’s here that the x-rays are being made, just outside the black hole's event horizon - its point of no return, about 2500 parsecs, or a little less than 48 quadrillion miles from Earth.