Saturday: 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.
Sunday: Venus is two and a half fists and Saturn is a half a
fist above the west-southwestern horizon at 6:30 p.m. Does Venus look
exceptionally bright tonight? It is at its brightest of the year.
Monday: This Presidents 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 strong 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 in on 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: Are you going to skip a winter vacation
because flights are too expensive? Then take a virtual vacation to a black
hole. NASA scientists have just developed a visualization to show how light
moves in the vicinity of a black hole. Book your ticket at https://www.nasa.gov/universe/nasa-visualization-shows-a-black-holes-warped-world/.
Wednesday: 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.
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: Jupiter is six fists above due southwest and Mars is
six and a half fists above the southeastern horizon at 8:00 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.
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