The Ellensburg, WA sky for the week of March 21, 2020

Saturday:  Many artists have sung the song “Blue Moon”. But few have sung the song “Blue Planet”. It goes, in part “Blue Planet, you saw me standing with 27 others. Rolling around like a barrel. Without close sisters or brothers.” It’s about the planet Uranus, which orbits the Sun in a rolling motion and has 27 moons. Every one of Uranus’ moons is named after characters in works by William  Shakespeare or Alexander Pope. Uranus is one and a half fists held upright and at arm’s length above due west at 8:30 p.m., easily visible with binoculars. First find Hamal and Sheratan, two stars of similar brightness, two fists above the west-northwestern horizon and stacked vertically a half a fist apart from each other. Then move your binoculars straight left from Sheratan to a 19 Arietis, a star about one tenth as bright but still the brightest in the field of view. With 19 Arietis at the top of your field of view, Uranus will be near the center. Return to this same spot for the next few nights. If the point you are looking at moves compared to the neighboring points of light, you are looking at Uranus.

Sunday: Has there ever been life on Mars? Astronomers don’t know. But the Mars Curiosity Rover has been digging up some strong evidence that Mars was hospitable to life in the past. At the end of 2012, the first drilling assignment for Curiosity found clay-like minerals that form in the presence of water. In December 2013, scientists announced the strongest evidence yet for an ancient fresh-water lake in Gale Crater. Planetary geologist John Grotzinger said that Earth microbes would have thrived in this lake if they were placed there. Last year, astronomers at the European Southern Observatory’s Very Large Telescope in Chile found evidence that Mars once had an ocean that held more water than the Arctic Ocean and covered a greater percentage of Mars’ surface than the Atlantic Ocean does on Earth. Finally, November 2018, the InSight mission landed on Mars and almost immediately started digging to study the geology of Mars. While geology isn’t life, many scientists think there is a relationship between geologic activity and the favorability for life to evolve. In pop culture news, NASA just names a small rock on Mars Rolling Stones Rock after the legendary band. For more on Rolling Stones Rock, go to https://go.nasa.gov/MarsRocks. See Mars one fist above the southeastern horizon at 6:00 a.m. Over the next few days it will move away from bright Jupiter in the sky and towards Saturn.

Monday: Mercury will be as far away from the Sun in the sky as it will get this orbital cycle. This "farthest away" point is known as the planet's greatest elongation. Since Mercury is in the morning sky, it is west of the Sun and this occurrence is called the greatest western elongation. This morning, Mercury is a half a fist above the eastern at 6:30 a.m. Over the next few weeks, Mercury will move toward the Sun in the sky. By late May, it will be visible in the evening sky.

Tuesday: This evening, Venus is as far away from the Sun in the sky as it will get this orbital cycle, known as the planet’s greatest eastern elongation. Tonight is one of the best nights of the year to observe Venus because it is far from the Sun at sunset. Venus is three fists above due west at 8:30 p.m. Over the next two months, Venus will move toward the Sun in the sky and get closer to the horizon. By early June, it will be lost in the glare of evening twilight.

Wednesday: The bright star Arcturus is three and a half fists above the eastern horizon at 11:00 p.m.

Thursday: Saturn, Mars, and Jupiter make a line in the early morning sky. Jupiter is one and a half fists above the south-southeastern horizon. Reddish Mars is less than a half a fist to the lower left of Jupiter and yellowish Saturn is less than a half a fist to the left of Mars.

Friday: April is Global Astronomy Month (GAM). While many astronomy experiences come from using your eyes, you can also experience astronomy with your ears and your hands. GAM has numerous arts initiatives including a Cosmic Concert and an AstroCrafts Project. Go to https://astronomerswithoutborders.org/gam2020-programs/program-schedule-2020.html for more information about events.

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.