The Ellensburg, WA sky for the week of January 11, 2020

Saturday:   Last Saturday's planetarium show had some technical difficulties. So, we will be redoing the show today from noon to 1 p.m. CWU physics graduate and future science teacher Jessica Kisner will give a show about the winter sky. The nights are long and the sky is (sometimes) crisp and clear. So you ought to know what you are looking at. The show is free and open to all ages. There will be a show at noon on the first Saturday of every month of the school year hosted by different CWU astronomers and astronomy educators. The CWU Lydig Planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map.

Sunday: How do you study the life cycle of a dog? Easy. Get a dog from the animal shelter, care for it for 15 years and study it. How do you study the life cycle of a star? Easy. Pick a star, watch it for a few billion years, and…. Wait a minute. Astronomers can’t observe something for a few billion years. Instead, they study stars that are at different points in their long life cycle and piece together the information from those different stars. What they do is like studying a one-year-old dog for a few minutes, then studying a different two-year-old dog for a few minutes, and so on. The sky in and near the constellation Orion provides an example of four objects at different points of star life.

First, find Rigel, the bright star in the lower right corner of the constellation Orion. This star, rapidly burning its fuel for a high energy but short-lived existence, is three and a half fists held upright and at arm’s length above due south at 10 p.m. It was not, is not, and never will be like our Sun. However, about one fist up and to the left are the three objects of Orion’s sword holder. The middle “star” is really a star-forming region called the Orion nebula. There you’ll find baby Suns. Now, look about two fists to the right and one fist down from Rigel. You should be looking at a star that is about one tenth as bright as Rigel but still the brightest in its local region. The third star to the right of that star is Epsilon Eridani, the most Sun-like close and bright star. Betelgeuse, in the upper left corner of Orion, is a star at the end of its life that started out life a bit larger than the Sun. Betelgeuse has been in the astronomy news lately because it has fallen from the 10th brightest star to the 21st brightest star in the night sky. Supergiant stars such as Betelgeuse are unstable and vary in size and shape over their years as a supergiant. These variations lead to variations in brightness. Astronomers think that a few different variation patterns that lead to slight changes in brightness individually are all happening at the same time, leading to a larger drop in brightness. For more information, go to https://www.skyandtelescope.com/observing/fainting-betelgeuse. 

Monday: When someone is angry, they may say “I’m seeing red.” For the next few days, people who  observe the morning sky will also see red. Mars and its rival Antares are neighbors in the sky for the next few days. Lest you think I am drumming up a fake rivalry, the prefix “ant” means “against”, “opposite”, or “rival”.  Ares is the Greek counterpart to the Roman god of war, Mars. So Antares literally means “rival to Mars”. At 7:00 a.m., Antares is one fist above the south-southeastern horizon and Mars is half a fist above it.

Tuesday: Venus is one and a half fists above the southwestern horizon at 6:00 p.m.

Wednesday: These next two weeks are the coldest of the year so it is time to turn up the furnace. Fornax the furnace is one fist above due south at 7 p.m.

Thursday: Have you ever looked down on the ground and spotted a penny? In Yakima? While you were standing in Ellensburg? If you have, then you may be able to see the star Hamal as more than just a point of light. It has an angular diameter that can be directly measured from Earth. Hamal, the brightest star in the constellation Aries the ram, has the same angular diameter as a penny 37 miles away. (For comparison, the moon is about half the diameter of a penny held at arm’s length.) Hamal is three fists above due west at 11:00 p.m.

Friday: Jupiter is finally starting to come out of the glare of the Sun in the morning sky. It is just above the southeastern horizon at 7:00 a.m. You’ll need a flat and clear horizon to see it.

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.

The Ellensburg, WA sky for the week of January 4, 2020

Saturday: The CWU Physics Department and the College of the Sciences is hosting its monthly First Saturday planetarium show today from noon to 1 p.m. CWU physics graduate and future science teacher Jessica Kisner will give a show about the winter sky. The nights are long and the sky is (sometimes) crisp and clear. So you ought to know what you are looking at. The show is free and open to all ages. There will be a show at noon on the first Saturday of every month of the school year hosted by different CWU astronomers and astronomy educators. The CWU Lydig Planetarium is room 101 in Science Phase II, just off the corner of 11th and Wildcat Way, H-11 on the campus map found at https://www.cwu.edu/facility/campus-map.

Sunday: If the Sun looks big today, your eyes are not playing tricks on you. The Earth was at perihelion a little before midnight last night, Pacific Standard Time. If you dig out your Greek language textbook, you’ll see that peri- means “in close proximity” and helios means “Sun”. So, perihelion is when an object is closest to the Sun in its orbit, about 1.5 million miles closer than its average distance of 93 million miles. Since it is winter in the Northern Hemisphere now, the seasonal temperature changes must not be caused by the Earth getting farther from and closer to the Sun. Otherwise, we’d have summer when the Earth is closest to the Sun. The seasons are caused by the angle of the sunlight hitting the Earth. In the winter, sunlight hits the Earth at a very low angle, an angle far from perpendicular or straight up and down. This means that a given “bundle” of sunlight is spread out over a large area and does not warm the surface as much as the same bundle in the summer. For the Northern Hemisphere, that very low angle occurs in December, January and February.

Monday: The Moon makes a triangle with the open star clusters called the Pleiades and the Hyades throughout the night. At 6:00 p.m., the Moon is above the east-southeastern horizon. The Hyades cluster is about a fist to the lower left of the Moon and the Pleiades is about a fist to the upper left of the Moon. By 4:00 a.m., they are nearly in line with each other just above the west-northwestern horizon.

Tuesday: Do you look into a nursery and say, “it’s a boy” or “it’s a girl”? Not me. I say, “It’s a star”. Of course, I like looking into a stellar nursery – a star-forming region such as the Orion Nebula in the middle of Orion’s sword holder. The Orion Nebula looks like a fuzzy patch to the naked eye. Binoculars reveal a nebula, or region of gas and dust, that is 30 light years across. The center of the nebula contains four hot “baby” stars called the Trapezium. These hot stars emit the ultraviolet radiation that causes the Nebula’s gas to glow. The Orion Nebula is nearly four fists above due south at 10:30 p.m.

Wednesday: Venus is one and a half fists above due southwest at 5:30 p.m.

Thursday: Just over a year ago, the NASA probe called New Horizons sent back the first detailed images of Arrokoth, also called 2014 MU69, a Kuiper Belt object that formed in its current state about 4.5 billion years ago. Arrokoth looks like a 30-kilometer long reddish snowman spinning through space. Check out the newest images and the latest information at http://pluto.jhuapl.edu/. Arokoth means “sky” in the Powhatan/Algonquian language. Astronomers first nicknamed the object “Ultima Thule”, meaning a place beyond the known world. But Nazis and Neo-Nazis had co-opted that term long ago, leading to the official, much more meaningful name. Arrokoth is red, just like Mars. You can’t see Arrokoth in the sky. But you can see Mars at 6:30 a.m., one and a half fists above the southeastern horizon.

Friday: Tonight’s Full Moon is called the Full Wolf Moon since wolves tend to howl more often in the cold winter nights.

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.

The Ellensburg, WA sky for the week of December 28, 2019

Today: Say goodbye to one of the bright summertime stars. Fomalhaut, in the constellation Piscis Austrinus or the southern fish, is a half a fist above the south-southwestern horizon at 7:00 p.m.

Sunday: Is your favorite someone lamenting that she didn’t get that space-related calendar that she wanted? Are you sad that you ran out of money and can’t fulfill her last-minute wish? Do you wish you could spend more quality time with her? Worry not. NASA has a free English or Spanish language calendar available for download at https://eospso.nasa.gov/publications/25.  Spend many hours reading about NASA scientists and projects.

Monday: “Far out, man. Astronomers just discovered the farthest out object in the Solar System and nicknamed it Farout.” This Kuiper Belt object is more than 100 times farther from the Sun than Earth is, more than twice as far as Pluto is. For more information about Farout, go to https://goo.gl/YtGsRE. Look in the early morning sky for some not so far out objects. If you care more about the nearest objects, call them “near-bys”, look for Venus, our nearest and brightest neighbor, is about one and a half  fists above the southwestern horizon at 5:00 p.m. The waxing crescent Moon, our nearest neighbor, is low in the south-southwestern sky.

Tuesday: The bright star Regulus is one and a half fists above the eastern horizon at 10:00 p.m.

Wednesday: Today is the day we celebrate the anniversary of something new – a new classification of celestial objects. Giuseppe Piazzi discovered Ceres [pronounced sear’-ease], the first of what are now called “asteroids”, on January 1, 1801. Ceres is the largest asteroid in the belt between Mars and Jupiter. At first, Piazzi thought it was a star that didn’t show up on his charts. But, he noted its position changed with respect to the background stars from night to night. This indicated to him that it had to be orbiting the Sun. The International Astronomical Union promoted Ceres to the status of “dwarf planet” in August of 2006.

Thursday: Has it been tough to wake up this past week? It should have been because the sunrise has been getting a little later since summer started. I know. I know. December 21 was the shortest day of the year. But, because the Earth’s orbit around the Sun is elliptical and not circular, the Earth does not travel at a constant speed. It moves faster when it is closer to the Sun and slower when it is farther away. This leads to the latest sunrise occurring in early January and the earliest sunset occurring in early December, not on the first day of winter, the shortest day of the year. On the first day of winter, however, the interval between sunrise and sunset is the shortest. For more information, go to http://goo.gl/SJC5r.

Friday: Late tonight and early morning’s weather forecast: showers. Meteor showers, that is. The Quadrantid meteor shower peaks late tonight and early tomorrow morning between midnight and dawn. Meteor showers are named after the constellation from which the meteors appear to originate. That makes this shower mysterious because there isn’t any constellation with this name now. The shower was named after Quadrans Muralis, an obsolete constellation found in some early 19^th century star atlases. These meteors appear to come from a point in the modern constellation Draco the dragon. This point is about three fists above the northeast horizon at 1 a.m. This year, the waning gibbous Moon will set well before dawn so you may be able to see many meteors in the hours before sunrise. Meteors are tiny rocks that hit the Earth and burn up in the atmosphere. Most meteors are associated with the path of a comet. This shower consists of the debris from an asteroid discovered in 2003. Keeping with the comet-origin paradigm, astronomers think the asteroid is actually an “extinct” comet, a comet that lost all of its ice as it passed by the Sun during its many orbits. For more information about the Quadrantid meteor shower, go to https://earthsky.org/?p=4287.   

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.