Saturday: Tonight is a great night to look for the Big Dipper. Tomorrow will be a great night to look for the Big Dipper. In fact, every night for many centuries will be great nights to look for the Big Dipper. But the Big Dipper’s shape slowly changes over many, many, many, many centuries. (Have I reached my word count yet?) Tens of thousands of years ago, it didn’t look like a dipper and tens of thousands of years from now, it will no longer look like a dipper. For a short video simulation of the changing Big Dipper, go to https://youtu.be/txJH8RlIoXQ. For a look at the current Dipper, face northeast at 8:00 p.m. The lowest star, Alkaid, is two fists held upright and at arm's length above the horizon.
Sunday: The weather has been cold. It will feel good to
think ahead about spring. The spring triangle, the nearly equilateral triangle
of Spica, Arcturus, and Denebola. It is called the spring triangle because the
three stars are rising as the Sun is setting near the start of spring. Since
spring is currently a month away, the three stars rise a few hours after
sunset. By 11:00 p.m., the bright star Arcturus is two and a half fists above
due east. Spica is one fist above the southeastern horizon. Denebola, the dimmest
of the three but still the 60th brightest star in the night sky, is four and a
half fists above the southeastern horizon.
Monday: Mars is a little bit below the Moon; both are high
in the southwestern sky at 9:00 p.m. Observers in eastern Greenland, the
Norwegian island of Svalbard, and northwestern Russia will see the moon occult,
or block, Mars.
Tuesday: Last week we learned that Clyde Tombaugh discovered
the first planet 9. Will you discover the new Planet 9? You and thousands of
others will have the opportunity to comb through images of the sky from NASA’s
Wide-field Infrared Survey Explorer (WISE). You’ll view short “flipbook” movies
of the same patch of sky on different nights. Any point of light that moves
could be Planet 9 or another undiscovered Solar System object. Read about how
you can join the search for Planet 9 at https://www.zooniverse.org/projects/marckuchner/backyard-worlds-planet-9.
Wednesday: Venus and Jupiter are less than a half a degree
apart from each other, one and a half fists above the western horizon at 7:00
p.m. They are so close in the sky; you couldn’t fit the Full Moon between them.
Thursday: On these late winter mornings, it is still
difficult to get going. You just want to plop into a chair and sit still. But
are you really sitting still? You’re moving at about 700 miles per hour due to
the rotation of the Earth on its axis and 66,000 miles per hour due to the
revolution of the Earth around the Sun. If that’s not enough, the entire solar
system is orbiting the center of the galaxy at a whopping 480,000 miles per
hour! So, while you may be sitting still with respect to your living room (and all
the overachievers in your house), you are NOT sitting still with respect to the
center of the galaxy. For more information about this concept, go to https://nightsky.jpl.nasa.gov/docs/HowFast.pdf.
Friday: More celestial evidence that spring is around the
corner. The wintertime constellation Orion is moving towards the western
horizon. Orion’s belt is two and a half fists above the southwestern horizon at
10:00 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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