Friday, August 20, 2021

The Ellensburg, WA sky for the week of August 21, 2021

 

Saturday: Jupiter, Saturn, and the Full Moon make a small triangle in the sky. At 9:00 p.m. low in the southeastern sky, Jupiter is about a half a fist to the upper left of the Moon and Saturn is about two fists to the upper right of the Moon. The three celestial objects will move through the sky together all night.

Sunday: Arcturus is three fists held upright and at arm’s length above the western horizon at 9:00 p.m. This star, whose name means bear watcher, is the brightest in the sky’s northern hemisphere. It follows Ursa Major, the Great Bear, around the North Star. Arcturus is the closest giant star to Earth. It is one of the few stars whose diameter can be measured directly rather than being inferred from its density and mass, which themselves are derived from other parameters. 

Monday: Have you ever gone to a family reunion, looked around and asked, “How in the world are we related to each other?” Astronomers look around the Solar System and wonder if there is life anywhere else that we are related to. The Mars Science Laboratory landed on Mars in 2012 to investigate whether it ever had conditions favorable for life. The Venus Express studied the atmosphere of Venus from 2006 to 2014. NASA plans to launch the Europa Clipper in 2023 to look for evidence of current or past life in the Jovian moon’s ice-covered ocean. NASA just started working on the Dragonfly mission to fly a drone through the atmosphere of Saturn’s moon Titan to study clues for the origin of life. To learn more about the search for life in the Solar System and beyond, go to https://www.astrobio.net/, a NASA-sponsored popular science magazine. While you won’t see anyone waving back, you can see Venus right after sunset. At 8:30, it is a half a fist above the west-southwestern horizon. The Mercury-bound probe BepiColombo passed by Venus in early August and snapped a close-up image, found at https://stardate.org/astro-guide/gallery/just-passing.

Tuesday: Deneb is straight overhead at 11:30 p.m. When you look at Deneb, you are seeing light that left Deneb about 1,800 years ago.

Wednesday: All stars rotate. Our Sun takes a little less than one Earth month to rotate once on its axis. Astronomers studied the relationship between mass, stellar rotation, and planetary formation by aiming NASA’s recently retired Kepler space telescope toward the Pleiades open star cluster. All 1,000 stars in this group are nearly the same age, 125 million years old. Since all of the stars are the same age and formed from the same set of materials, astronomers have the ideal “laboratory” to isolate the role star mass plays on star rotation and evolution. Read more about the findings at http://goo.gl/osijIY. See the Pleiades for yourself, one fist above the east-northeastern horizon at 11:30 p.m.

Thursday: Seventeenth century astronomers documented the appearance of a new star, or “nova”, in 1670. However, as modern astronomers studied the records of the star, called Nova Vulpeculae 1670, they realized it didn’t have the characteristics of a typical nova because it didn’t repeatedly brighten and dim. It brightened twice and disappeared for good. Turning their telescopes to the region, they discovered the chemical signature to be characteristic of a very rare collision of two stars. For more information about this discovery, go to http://goo.gl/rJnC2G. Nova Vulpeculae 1670 is right below the binary star system Alberio, the head of Cygnus the swan. Alberio is seven fists above due south at 10:00 p.m.

Friday: The bright star Sirius is rising right before the Sun. It is a half a fist above the east-southeastern horizon at 5:30 a.m.

The positional information in this column about stars and planets is typically accurate for the entire week. For up to date information about the night sky, go to https://nightsky.jpl.nasa.gov/planner.cfm.

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