Saturday: Red is a popular Christmas color. It is also a
popular star color. And R Leporis, also known as Hind’s Crimson Star, is one of
the reddest stars in the sky. It is a star near the end of its life that has
burned its helium nuclei into carbon. Convective currents, like those in a pot
of boiling water, bring this carbon to the surface. There it forms a layer of
soot that scatters away the light from the blue end of the visible spectrum
leaving the light from the red end of the spectrum to reach our eyes. For more
information about Hind’s Crimson Star and a list of other deep red stars, go to
http://goo.gl/EnhRe4. Hind’s Crimson star is
one fist to the lower right of Rigel, the brightest star in Orion. You’ll need
binoculars or a small telescope to see Hind's Crimson star. But you can easily
spot Rigel two and a half fists held upright and at arm’s length above the
south-southeastern horizon at 10:00 p.m.
Sunday: At 2:01 a.m., Pacific Standard Time, late
tonight/early tomorrow the Sun reaches its lowest point in the sky with respect
to the background stars. This point is called the Winter Solstice. During the
day that the Sun reaches this point, your noontime shadow is longer than any
other day of the year. Also, the Sun spends less time in the sky on the day of
the Winter Solstice than any other making this the shortest day of the year.
Even though it is the shortest day of the year, it is not the day with the
latest sunrise or the earliest sunset. The latest sunrise is during the first
week in January and the earliest sunset is during the second week in December.
The Sun is at its southernmost point with respect to the background stars on
the day of the winter solstice. This means the Sun spends the least amount of
time above the horizon on that day. But, the Sun rise and set time depends on
more than its apparent vertical motion. It also depends on where the Sun is on
the analemma, that skinny figure-8 you see on globes and world maps. During the
second week in December, the Sun is not quite to the bottom of the anaemma.
But, it is on the first part of the analemma to go below the horizon. During
the first week in January, it is on the last part of the analemma to rise above
the horizon.
Monday: This is the night of THE Great Conjunction In The
Sky! Well, a great conjunction in the sky. Actually, a pretty good conjunction.
Jupiter and Saturn are 6 arc minutes apart tonight. That is one tenth of a
degree. For comparison, Alcor and Mizar, the close-together stars at the bend
in the Big Dipper handle are 12 arcminutes apart. You’ll find Jupiter and
Saturn low in the southwestern sky right after sunset. Read more about it at
http://tiny.cc/6px6tz.
If you want to hear about a really Great Conjunction, talk
to an ancient Babylonian. On the morning of March 25, 185 BCE, Mercury, Venus,
Mars, Jupiter, and Saturn were within seven degrees of each other. That means
they could have all fit into the cup of the Big Dipper. Two astronomers
recently identified a small piece of clay with a cuneiform description of the
conjunction. Read more about this conjunction at http://tiny.cc/fsx6tz.
Tuesday: Are you disappointed because you are not going
anywhere for Christmas? Why not take a (virtual) trip to outer space using
Google’s new visualization tool called 100,000 Stars. It shows the stars in our
neighborhood in a very good 3-D simulation. The Sun is initially at the center.
If you zoom in, you can click on neighboring stars and learn more about them.
Go to http://stars.chromeexperiments.com/
for the simulation. It works best on a Chrome browser.
Wednesday: Mars is about a half a fist to the upper right of
the Moon. They are five fists above due south at 7:30 p.m.
Thursday: Just before Christmas, you look for junk to clean
out of your closets so you can re-gift it. I mean, so you can throw it out or
recycle it. NASA’s Meter Class Autonomous Telescope on Ascension Island is a
key tool in a program tracking about 22,000 pieces of space junk. Some of this
junk is dangerous. The International Space Station occasionally performs debris
avoidance maneuvers to keep its panels and sensitive instruments safe. For more
information about the project, go to http://goo.gl/Kxgihd.
Friday: Where is the one who has been born King of the Jews?
We saw Jupiter being eclipsed by the Moon in the east and have come to worship
him” (Matthew 2:2, Bruce Palmquist version, informed by Michael Molnar). There
are many theories as to the physical explanation of the Star of Bethlehem, the
celestial object that guided the wise men to the location of Jesus. Some people
think it was a recurring nova, a star that explodes. Some think it was a close
alignment of bright planets. Some think it was a miracle that requires no
physical explanation. In 1991, astronomer Michael Molnar bought an ancient
Roman Empire coin that depicted a ram looking back at a star. Aries the ram was
a symbol for Judea, the birthplace of Jesus. The Magi, or “wise men”, who
visited the baby Jesus practiced astrology and would have been looking in that
region of the sky for the king prophesied in the Old Testament. Molnar, a
modern day wise person, used sky simulation software to model the positions of
planets and the Moon in the region of Aries. According to his model, Jupiter
was eclipsed, or blocked, by the Moon on the morning of April 17, 6 BC. A book
written by the astrologer of Constantine the Great in 334 AD supports Molnar’s
theory. The book describes an eclipse of Jupiter in Aries and notes a man of
divine nature born during this time. See https://goo.gl/o89A4o
for more information.
At 5:00 p.m., the Moon is in the dim constellation Aries,
about three fists above the eastern horizon. Jupiter is still snuggling with
Saturn, now in the southeastern sky.
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.
