Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
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Photo of the Week.. A misty summer sunrise brings
memories of warmer weather.
Astronomy news for the week starting Friday, December 19, 2003.
Best wishes for a fine holiday season.
The Moon rambles along through the zodiac toward its new phase,
which it will pass on Tuesday, December 23, shortly before
sunrise in North America. The early part
of the week, it will appear as a slimming crescent in the dawn sky,
while to the end of the week it will be seen climbing out of evening twilight.
You might catch your first glimpse of it low in the southwest just
after sundown on Wednesday, the 24th, Christmas Eve. Then on
Christmas night we will be treated to a lovely pairing of the Moon with Venus, the Moon lying to
the left of the brilliant planet, the nighttime side of the lunar
disk glowing softly with light reflected from the Earth, the sight
poetically called "the old Moon in the new Moon's arms." Almost
exactly a day before new, the Moon passes perigee, when it is just
over five percent closer than average, the combination with the new
phase bringing especially high tides to the
coasts.
As twilight ends, look for
Saturn rising to the northeast in Gemini and for Mars
transiting the meridian.
Jupiter then rises in the east shortly before midnight.
The big event of the week, however, deals not with the Moon and
planets, but with the Sun, which
will pass the winter solstice in Sagittarius the night of Sunday the
21st to mark the beginning of
astronomical winter. For North America, the actual date
depends on where you are. On the east coast, the Sun bottoms out
at 23 degrees 26 minutes below the equator at 2:04 AM Eastern
Standard Time the morning of Monday the 22nd. In the middle of the
continent, the time will be 1:04 AM CST, 12:04 AM MST, while on the
west coast the event takes place at 11:04 PST on Sunday the 21st,
the date also for Alaska and Hawaii (respectively at 10:04 and 9:04
PM).
At the moment of solstice passage, the Sun will appear as far to
the south at noon as possible, will rise as far as possible to the
south of east, and will set its maximum to the southwest. In the
northern hemisphere, we will experience our least heating, shortest
day, and longest night, while southern hemisphere residents will
have their longest day and shortest night. The Sun will also pass
overhead at the Tropic of Capricorn, at a latitude of 23
degrees 26 minutes south. From that moment on, the Sun will begin
to move to the north, though so slowly at first that mid-northern
latitudes will continue to chill. The next passage of note will
mark the beginning of spring, which will
take place the morning of March 20 on the east coast, the evening
of the 19th on the west, the event again closely coinciding with
new Moon.
Around 8 PM look for a stack of constellations that begins with Andromeda nearly overhead in
mid-latitudes, then cascades to the south through Triangulum and Aries (both flat triangles), through the head of Cetus, and then down to western Eridanus, the River, which announces
the arrival heart of the winter constellations, including mighty Orion.
