Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. Planet Earth: Misty beauty fills
the Swiss Alps, a lonely river winding between them as they march
off to the horizon.
Astronomy news for the week starting Friday, December 5, 2003.
Welcome to the last month of the year, and to the approach of
winter. The Moon goes through its full phase on Monday, December 8,
and in honor of the season is known as the "Cold Moon," or the
"Long Night Moon." Nights are getting longer, days shorter (for us
in the northern hemisphere), as the Sun is already down near its
lower depths, 22 or so degrees below the celestial equator and not
far from bottoming out at the winter
solstice. Because sunlight at our mid-northern latitudes is
coming in at a shallow angle, it is spread out over the landscape, and the ground and air turn
cold even as we are getting slightly closer to the Sun on our
somewhat elliptical orbit.
After passing full, the Moon wanes through gibbous the
remainder of the week, passing north of Saturn two days later, during the afternoon of
Wednesday, the 10th. That night, the lunar disk will be seen to
the northeast of the ringed planet, which rises in Gemini around 6:30 PM just about
half an hour before still-bright
Mars transits the meridian to the south. The red planet is moving
to the northeast against the background stars, and is now near the
Pisces-Aquarius border. Early in
the evening, look to the southwest to find brilliant
Venus, the planet now setting shortly after twilight ends. It
makes a lovely contrast against the fading light of the sky as
night grows on. As Venus sets, Mars transits, and Saturn rises all
at just about the same time. Down and to the right of Venus is Mercury, which reaches its greatest
eastern elongation from the Sun on Tuesday, the 9th. In the other
direction, watch for the rising of
Jupiter about half an hour before midnight, the giant planet in
far southern Leo not far from its
border with Virgo.
This seems to be " asteroid week." Of the first four known asteroids
(the set of little bodies between Mars and Jupiter), three make
themselves known, as No. 3
Juno passes conjunction with the Sun on Friday, the 5th, no. 2
Pallas ceases retrograde motion on Monday the 8th, and, and no.
1 Ceres (only 590 miles, 950 km in diameter) is
actually occulted by the Moon on Thursday, the 11th, though the
event is visible only from the South Atlantic. The asteroids
probably would have accumulated to form a real planet had Jupiter
not made a mess of their orbits, and instead now sends them
crashing together to grind themselves down. A few move to the
inner Solar System, where upon hitting the Earth, they are known as
meteorites. Speaking of which, keep your eye out in
the morning for the build-up to the Geminid meteor shower, which
peaks the morning of Saturday, the 14th, the
Geminids the debris of Comet Phaeton (though the bright Moon
will be in the way).
The stars of the Andromeda
myth are at their best, the Maiden overhead in early evening, her
Mother, Cassiopeia the Queen,
crossing the sky to the north of the zenith, the Great Square of Pegasus now
shifting to the west. Below Andromeda and Pegasus, find the
sprawling figure of Pisces, and
to the south of the Fishes find the tail of Cetus the Whale, marked by lonely Deneb Kaitos.
