Bakersfield Night Sky — November 2, 2024
Tickets are now on sale for the two November shows at the William M Thomas Planetarium: “Incoming!” playing on November 7 and “Moon Base: The Next Step” playing on November 21. “Incoming!” is about the small bodies of our solar system, asteroids and comets, that can tell us about the beginnings of the solar system because they haven’t changed since they formed with the planets 4.6 billion years ago. These remnants continue to hit the planets, including Earth.
“Moon Base” is about the next stage of human exploration and settling of the moon. The moon will become our first “staging post” from which Mars and the rest of the solar system becomes tantalizingly closer.
The National Oceanic and Atmospheric Administration (NOAA) has several satellites looking down at the Earth’s atmosphere to gather the data we need to make weather predictions. NOAA has a new satellite in orbit to gather the data it needs for its second task: making space weather predictions. Space weather is the ever-changing interplanetary environment produced by charged particles spewed out by the sun. The charged particles include the ever-present solar wind streaming out from the sun at over a million miles per hour as well as large discharges of much more energetic bursts from flares and coronal mass ejections (CMEs) that could damage our commercial and military satellites and electrical power grid.
The new NOAA Geostationary Operational Environmental Satellite (GOES) is the nineteenth one in the set, so it’s known as GOES-19 and this one includes the ability to look at the sun while it also looks at Earth. It uses a coronagraph to block out the bright surface of the sun, creating a perpetual eclipse, so it can watch for CMEs like those that produced the magnificent aurora displays we had earlier this year. Although some other satellites have coronagraphs as well, they are NASA, ESA, or Indian ones for doing science research. GOES-19’s coronagraph is the first one dedicated to NOAA for space weather observations.
As the temperatures drop and nights lengthen, we’re now able to see the beautiful Pleiades star cluster rising in the east in the early evening. It lies at the shoulder of the constellation Taurus and as such, it precedes the other bright constellations of winter: Auriga with bright Capella at one corner, Orion with the three belt stars and red Betelgeuse and blue-white Rigel at opposite corners, Gemini with Pollux and Castor, Canis Minor with bright Procyon at one end, and Canis Major with the brightest night star of all, Sirius. This winter we’ll also have super-bright Jupiter among the stars of Taurus.
Without a telescope or binoculars, most people can pick out six of the brightest stars in the Pleiades. Some young and very sharp eyes can pick out a few more—one student of mine a number of years ago said he could see nine. Ordinary mortals see just six. With a telescope, several hundred stars can be seen. They lie about 444 light years away from us. The brightest stars of the cluster and the ones we can see without optical aid are hot blue stars much hotter than the sun and many thousands of times more luminous than the sun. The cluster formed about 100 million years ago and will probably survive another approximately 250 million years before the differential gravity stresses it experiences as it orbits the Galaxy will dissolve the cluster. Telescopes reveal the bluish reflection nebula surrounding the stars which is light from the hot stars scattering off dust particles in a cloud that the cluster is currently passing through.
Stories about the Pleiades cluster go back thousands of years, including in the Bible and even more ancient civilizations. The Pleiades are depicted on the Nebra Sky Disc I wrote about in the first of my August columns. The Nebra Sky Disc is the oldest concrete representation of the sky that had been in use 3600 to 4300 years ago. Seven dots are shown on the disc. An image of seven stars in the Pleiades in Lascaux, France dates back several thousand years earlier than that. Rock art in Walinynga of central Australia that is at least 3000 years old shows seven stars.
Seven stars, not six. Stories from many of the ancient civilizations will talk about seven sisters and then describe what happened to the lost seventh sister. A fascinating article by Ray Norris in the November issue of Sky and Telescope gives some of the details of these ancient stories and offers an astronomical explanation of what happened to the seventh sister. Using the exquisite data from the Hipparcos and Gaia space telescopes about the internal motions of the Pleiades stars, he and his son found that the stars Pleione and Atlas were once much farther apart, so that ancient people would have been easily able to see them distinctly apart. The dimmer Pleione is now much closer to Atlas and is lost in the glare of Atlas.
The intriguing thing is that the separation was great enough many tens of thousands of years ago when Homo sapiens was still in eastern Africa. Could these stories of the seven sisters date back to long, long before anything was written down? A research team of anthropologists using 55,000 stories from 1500 ethnic groups were able to trace stories of the Pleiades and Orion back to those prehistoric times of our beginnings in Africa before the future Europeans migrated northwest and the future Aboriginal Australians headed southeast. The Seven Sisters may be oldest story ever told!
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Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
