Skywatch for the week of November 1, 2021
Mon Nov 1, 2021 CROSS QUARTER DAY
Today is the final cross-quarter day in our calendar. The quarter days mark each season’s beginning: March 21st for spring; June 21st for summer; September 21st for autumn; and December 21st for winter. The cross-quarter days divide each of these seasons in half: February 2nd, which is winter’s midpoint, called Imbolc by the ancient Celts; and in old calendars it was called Candlemas; not too long ago, it also picked up the name Groundhog’s Day. May 1st is the midpoint for spring, and was called Bealtane. August 1st, the middle of summer, was called Lunasadh or Lammas; and today, November 1st, is All Saints Day in the Church calendar, but also Samhain, the beginning of the ancient Druid year. Samhain is a late harvest occasion, when the last of the crops are brought in. Nights are now noticeably longer than the days, which is why we’re returning to Standard Time this coming Sunday.
Tue Nov 2, 2021 HARLOW SHAPLEY Harlow Shapley born 11/2/1885
Over in the southwest this evening there is a concentration of globular star clusters. No, you can’t see them with the unaided eye, but with a telescope you could find them – and each cluster you see contains thousands and thousands of stars packed in tight by gravity. Globular star clusters are all around us, but about half of them are gathered into one small spot in the sky, near the constellation Sagittarius. An astronomer named Harlow Shapley, born on November 2nd, in 1885, realized the significance of this clustering of clusters. In 1920 he suggested that because the globular clusters seemed to be centered around Sagittarius, that it was probable that that marked the center of the Milky Way galaxy. He was right – our solar system is part of the Milky Way, but we’re not in the middle of it, we’re a little over halfway out toward its edge.
Wed Nov 3, 2021 ASTRONAUT TALK AT THE LYRIC
Thu Nov 4, 2021 FRED WHIPPLE
The American astronomer Fred Whipple was born November 5th, 1906. As a young graduate student he helped to plot the orbit of the newly discovered planet Pluto, and in the 1930’s he showed that meteor showers are the result of particles shed from passing comets. But he is best known for his work in comet theory: in 1950, he came up with the basic model for comet composition that is still in use today. It’s called the “dirty snowball” theory, and it proposes that comets are basically big chunks of frozen ice, mostly water ice, with lots of rocky pebbles and dust grains mixed in. When a comet approaches the sun, the ices melt or sublimate and form an atmosphere or coma, around the comet nucleus; the solar wind and the pressure of sunlight blow this atmosphere out into a long comet tail. When the Giotto spacecraft flew by Halley’s Comet and imaged its 20-mile-wide nucleus during the comet’s last appearance in 1986 it confirmed his theory.
Fri Nov 5, 2021 STEAM TALK: THE SECRET LIFE OF FISH
There will be a free lecture tomorrow night – that’s Saturday, November 6th, at 6 pm. The talk will be held at IRSC’s Hallstrom Planetarium, and it will feature a discussion about “The Secret Life of Fish.” Dr. Bill Tyler, the foremost authority at Indian River State College on the nature of all those things that swim in the sea, will discuss how fish do what they do so well. The lecture’s about 45 minutes in length, and following it, I’ll do a star talk about the current evening sky, and acquaint folks with a lot of constellations that are in a part of the heavens called “the celestial sea.” In addition to Pisces, there’s also a sea goat, a dolphin, another fish, a crane, and even a whale! After the talks, telescopes will be set up, weather permitting, to look at the planets Jupiter and Saturn. Again, no tickets needed, just get to the Planetarium before 6 pm tomorrow night.