Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week. A spectacular convecting anvilled
cloud breeds a thunderstorm below.
Astronomy news for the week starting Friday, January 27, 2006.
This is the week of the new Moon, the resulting darkened sky
rendering the stars at greatest
visibility. We begin with the Moon in a nearly invisible thin waning crescent state. After
passing new on Sunday January 29th, the Moon will enter its waxing crescent phase. Watch for
the ultra-thin crescent in western evening twilight the night of
Monday the 30th, and then admire its growth on successive nights,
the nighttime side glowing with earthlight. Less than a day after new,
the Moon passes through perigee,
where it is closest to the Earth along its rather elliptical orbit
(which takes it 5.5 percent closer to, then the same farther from,
the average distance of 384,400 kilometers, 238,900 miles). While
the Moon therefore continuously slightly changes its angular size,
the effect is too small to be visible to the eye. Invisible also
is the Moon's passage just south of Uranus on Tuesday
the 31st.
The planetary week really begins with Saturn in
opposition to the Sun
on Friday the 27th, the ringed planet firmly in Cancer just barely south of the Beehive Cluster. Opposite the
Sun, Saturn will rise at sunset, set at sunrise, and cross the sky
to the south at local midnight, giving it the best visibility of
the year. Well to the west of Saturn, rather high to the south as
the sky darkens, is reddish Mars (near the Aries-Taurus
border), which as February begins, transits the meridian about 6:30
PM. Gracing the sky through the early night hours, Mars now sets
shortly before 2 AM, about half an hour after Jupiter rises.
With Venus rising around 5:30 AM, the morning dawn sky sees
the two brightest of planets, Venus to the southeast, Jupiter (in
Libra) to the south,
each far outshining the brightest star. Jupiter finds itself
near two stars of beloved names, Zubenelgenubi (Alpha Librae) and Zubeneschamali (Beta), though much
closer to the former (which just to the west of the planet).
The winter stars are now in full
glory, striking Orion (the
Hunter, with the bright stars Betelgeuse and Rigel) crossing the meridian to the
south around 9 PM. He is surrounded by his retinue of famed
figures that include Taurus (the
Bull, with Aldebaran) to the
northwest, Auriga (the
Charioteer, with Capella) to the
north, Gemini (the Twins, with
Castor and Pollux) to the northeast, Canis Minor (the Smaller Dog, with Procyon) to the east, Canis Major (the Larger Dog, with brilliant Sirius) to the southeast, and finally
little Lepus (the Hare) to the
south, all giving us one of the great gatherings of the sky.
a contemporary of Isaac Newton, thus showing that even the faintest
of the sky's naked eye stars can carry their own charm.
