Saturday: According to Greek mythology, the beautiful princess Andromeda was chained to a rock next to the ocean. Cetus the sea monster was about to devour her in order to punish her family. It seemed that all was lost. But along came the great warrior Perseus, fresh off his defeat of the evil Gorgon, Medusa. The only similarity between Andromeda and Medusa was that Andromeda caused people to stand still and stare at her beauty while Medusa turned people into stone because of her ugliness. (And you thought you looked bad in the morning.) Even though Perseus’ standing as the son of King Zeus and the slayer of Medusa was probably enough to win Andromeda under normal circumstances, Andromeda’s impending death-by-sea-monster was not a normal circumstance. So, Perseus drove his sword into the sea monster's neck and killed it. In a little-known addendum to the story, Perseus carved “Percy (heart symbol) Andi” in the rock, thus originating the use of the heart symbol as a substitute for the word “love”.
You can find these lovers in the sky this Valentine’s Day.
Just remember it is rude to stare – because you never know who might turn to
stone. First, find the Great Square of Pegasus at 7:00 p.m. between one and a
half and three and a half fists held upright and at arm’s length above the west
horizon. The lowest star in Andromeda is the top star in the square. This
represents Andromeda’s head. Perseus is at her feet, nearly straight overhead.
Mirphak, the brightest star in Perseus, is about eight fists above the west
horizon. Perseus’ body is represented by the line of stars to the left and
right of Mirphak.
Sunday: On February 18, 1930, Clyde Tombaugh discovered
Pluto, at that time classified as the ninth planet. However, as astronomers
started discovering a lot of similar objects in that part of the Solar System,
they realized that they had a classification crisis on their hands. Should
everything in this region of the Solar System be named a planet? Eventually the
International Astronomical Union (IAU) reclassified Pluto and all future
Pluto-like objects as dwarf planets. This week you can celebrate the discovery
with the people at Lowell Observatory, the “home” of Pluto’s discovery. Go to https://iheartpluto.org/ for more
information about online events this weekend.
Monday: This President’s Day, let’s remember Abraham
Lincoln: 16th president, country lawyer, man on the penny, wrestler,
and astronomer. Astronomer? Well, maybe not an astronomer, but someone who used
observational evidence from the sky to solve a problem. In 1858, Lincoln
defended Duff Armstrong, a family friend who was accused of murder. The
prosecution thought they had a persuasive case because their primary witnesses
claimed to have observed the killing by the light of the nearly full moon,
which they called “Moon bright”. Let’s listen to the trial courtesy of the 1939
film, Young Mr. Lincoln.
Lincoln: How’d you see so well?
Witness: I told you it was Moon bright, Mr. Lincoln.
Lincoln: Moon bright.
Witness: Yes.
(Dramatic pause as Lincoln reaches for something)
Lincoln: Look at this. Go on, look at it. It’s the Farmer’s
Almanack (sic). You see what it says about the Moon. That the Moon… set at 10:
21, 40 minutes before the killing took place. So, you see it couldn’t have been
Moon bright, could it?
Lincoln used the known information about Moon rising and
setting times for August 29, 1858, as evidence in a trial. This is one of the
earliest uses of forensic astronomy. For more information about Lincoln’s
“almanac trial”, go to http://goo.gl/r83q4X.
Tuesday: It’s getting dark. The last remnant of twilight has
disappeared. Suddenly, you notice a large softly radiant pyramid of light in
the western sky. The base of this ghostly triangle is along the west horizon,
and the peak stretches two or three fists above the horizon. It is not really a
ghost. It is an effect called the zodiacal light. This light comes from
sunlight reflecting off dust grains in our solar system. The effect is the most
visible when the band of constellations called the zodiac makes a steep angle
with the horizon. You need a clear dark sky with no haze or light pollution to
see the zodiacal light. At its brightest, the zodiacal light rivals the light
of the central Milky Way. Look for the ghostly patch after twilight for the
next few weeks.
Wednesday: Mercury is a thumb width to the lower right of
the moon at 6:30 p.m., low on the western horizon.
Thursday: Two bright stars, Vega and Deneb, are hugging the
northern horizon together at 11:00 p.m. Vega, the brighter of the two, is less
than a half a fist above the north-northeastern horizon. Supergiant Deneb to
two and a half fists to the left of Vega, closer to due north.
Friday: Saturn is half a fist above the western horizon and
Jupiter is six fists above southeastern horizon at 7:30 p.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.
All times are Pacific Time unless noted.