Bakersfield Night Sky — August 18, 2024
Classes begin next week for Bakersfield College and faculty and staff have been eagerly preparing for a great new academic year. Next month I’m hoping to bring a new show to the William M Thomas Planetarium called “Mesmerica” in partnership with Worlds Ltd. The plan is to do three showings on each of the Saturday evenings in September. Hopefully by the time this appears in print, all of the contract work will be completed and if so, tickets will be available a few weeks later through Worlds. Instead of a science-based presentation like we usually show, Mesmerica uses a lot of vivid abstract imagery in conjunction with beautiful music created by James Hood to give an uplifting experience. You might be able to see some clips of it on the web but it’s an entirely different level of experience being immersed in it under the dome. If this experiment works out, we’ll do again in 2025. Our other regular public shows will be available through Vallitix as before.
The moon will be at full phase tomorrow night (August 19) residing among the stars on the right (west) side of Aquarius. Actually, full phase occurs at about 11:30 a.m. when the angle between the sun and moon reaches its greatest extent. With that being in the middle of the day, the moons on the nights of August 18 and 19 will about equally close to full phase, so some websites will say tonight is full phase instead of tomorrow night. Tonight the moon will be among the stars of Capricornus. On August 20 you’ll see a waning gibbous moon traveling across the sky right next to Saturn. They’ll be closest when they rise in the east, just one thumb width at arm’s length apart and drift further apart as the night progresses. Although the moon will be just 30+ hours after full phase and plenty bright, Saturn will be bright enough to pick out just to the right of the moon.
Astronomical twilight ends at about 9:10 p.m. tonight. High overhead you’ll see the Summer Triangle made of Vega in Lyra, Deneb at the tail of Cygnus, and Altair in the neck of Aquila. Father down closer to the ground, the spout of the Teapot part of Sagittarius will be due south. The center of our home Milky Way galaxy is just off the spout of the Teapot, so at 9:10 p.m. point yourself just slightly right (west) of due south to face the galactic center. If you’re under a dark sky far from the city lights, you’ll notice that the milky band is a bit wider in that direction because of the central bulge of the galaxy. Along other parts of the milky band, you’re looking only through the thin disk part of the galaxy.
In the direction opposite Sagittarius—towards Auriga and Taurus that rise around midnight to 1 a.m.—you’ll see the milky band get sparsest. The milky band doesn’t disappear completely because the sun and planets of our solar system are just two-thirds of the way out from the galactic center, leaving another one-third of the thin disk of stars and gas clouds still farther out than we are. The Milky Way of stars and gas clouds is about 100,000 light years across or over 79 million times larger than the diameter of Pluto’s orbit around the sun. Another way to compare our solar system to the Milky Way is if Pluto’s orbit was the size of a quarter dollar coin, then the Milky Way would stretch from Los Angeles to Pierre, South Dakota (i.e., the entire western United States).
All of the stars and gas are embedded within a much larger roughly spherical blob of dark matter that’s about three (or more) times larger than the star/gas part. That’s pretty typical of galaxies. The stars and gas in the galaxies we marvel at in our telescopes are just the “tip of the iceberg” of the galaxy structures. The galaxies cluster together and the galaxy clusters then cluster together in elongated, string-like structures called superclusters. If we could directly see the dark matter parts, we’d see a web-like structure of matter throughout the universe. Long ago, the universe was a lot smoother but over billions of years, gravity has been able to make the originally slightly denser parts much denser and the originally slightly less dense parts much emptier, so now it makes a web-like design that would make a cosmic spider proud.
By about 1:40 a.m. you’ll be able to see Jupiter and Mars rising in the east between the horns of Taurus. They are approximately two thumb-widths apart from each other with orange-red Mars to the lower left of much brighter white Jupiter. In the early morning of August 27, a fat waning crescent moon will make a lovely right triangle with the two planets—the moon at the top, Jupiter at the bottom right (ninety-degree vertex) corner and Mars at the lower left corner. By the following night, August 28, the moon will have moved far enough eastward to make almost a straight line with Jupiter and Mars. At the end of the month, the moon will be a very thin waning crescent rising just an hour before sunrise. Just to the right of the moon on that morning will be Mercury.
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Director of the William M Thomas Planetarium at Bakersfield College
Author of the award-winning website www.astronomynotes.com
