Saturday:
“Excuse me, do you have the time?”
“No, but
the Big Dipper does.”
You can use the
orientation of the Big Dipper to tell time with a precision of about 15-30
minutes. First, find the two stars at the far end of
the Big Dipper cup, the stars that do not touch the handle. Draw an imaginary
line segment starting at the North Star and passing through the two Big Dipper
cup stars. Now, draw a big circle around the North Star. Your circle is a
24-hour clock. Number the circle from 0 hours at the top, counterclockwise to
12 hours at the bottom of the circle, and back up to 24 hours at the top. (O
hours and 24 hours are the same on this clock because the day is 24 hours
long.) The hour number on the big circle closest to where your imaginary line
intersects this circle is called your raw time. Due to the location of the Big
Dipper compared to the rest of the stars, the time nearest the intersection
(the raw time) is correct for March 6. For any other night, subtract two times
the number of months the current date is after March 6 from the raw time. For
example, let’s say the imaginary line between the North Star and the Dipper
stars is pointed to the right. That means the raw time is 18 hours or 6 p.m. If
you made this observation on October 6, which is seven months after March 6,
you would subtract two times seven or 14 hours from the raw time. Thus, the time for November 6 is 18
hours minus 14 hours or 4 hours. In other words, 4 a.m. Don’t forget to convert
for daylight savings time if needed. For a more complete set of instructions,
go to http://goo.gl/02HmA. There is a simple “star clock” template and
instructions at http://goo.gl/SFKrE. Use this paper star clock whenever you
watch is broken.
Sunday: Saturn
is about a half a fist above the west-southwest horizon at 8 p.m.
Monday: Let
me tell you the story of the ghostly white figure that rises early in the
morning around Halloween. It appears to be a huge dim glow of white light that
rises up from the east in the pre-dawn sky. No, I’m not writing about the ROTC
student who has early morning physical training. I’m describing 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 sky
with no haze or light pollution to see the zodiacal light that will be visible
for the next week or so. At its brightest, the zodiacal light rivals the light
of the central Milky Way.
Tuesday: To
celebrate the start of school at CWU tomorrow, let’s sing a song of the season.
“Oh the weather outside is grand. And the fire is rightfully banned. There is
really no place to go. Let it snow, let it snow, let it snow. On Mars.” The
Mars Reconnaissance Orbiter has discovered evidence of carbon dioxide snow
clouds high above the surface of Mars.
Carbon dioxide, also called “dry ice”, exists in Mars south polar ice
cap and requires temperatures of nearly 200 degrees below zero Fahrenheit to
form. Astronomers were not sure how this polar cap gets replenished but the
discovery of carbon dioxide clouds may provide an answer. For more information,
go to http://goo.gl/shMTf. Mars is less than
one fist held upright and at arm’s length above the southwest horizon at 8 p.m.
Wednesday:
Venus is three fists above the east horizon at 6 a.m.
Thursday: “One
world, group hug, love everyone” philosophy: political borders are human-made
and can’t be seen from space. Real world, pragmatic discovery: some human-made
political borders CAN be seen from space. Since 2003, India has illuminated its
border with Pakistan to prevent illegal crossings. In August, astronaut Ron
Garan took a picture of the boarder from the International Space Station. For
more information, including the photo, go to http://goo.gl/mY8xG.
Friday: Jupiter
is a half a fist above the east-northeast horizon at 11 p.m.
The
positional information in this column about stars and planets is typically
accurate for the entire week.
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