Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. A fiery sunset announces the
coming night.
Astronomy news for the week starting Friday, February 13, 2004.
We begin the week on Friday the 13th with the Moon in its third quarter.
During the remainder of the week it will wane in its crescent phase
until it reaches new on the morning of Friday, the 20th. In
between, on the morning of Monday the 16th, our neighbor passes perigee,
where it is 5.5 percent closer to us than average. A bit over a
day before new, on Wednesday the 18th, it glides invisibly south of
Neptune, which has only recently cleared the Sun. As the Moon's
crescent slims, watch for growing Earthlight on the lunar nighttime
side glowing softly in morning twilight.
It is the evening sky, however, that now holds the delights, not
the morning, as all the ancient planets but
Mercury put on a lovely show. Its brilliance punctuating
western evening twilight, Venus leads them all. To the southwest
find much dimmer reddish Mars.
Falling only slowly behind the Earth, the red planet moves
liesurely to the east against the stars south of Aries and north of the head of Cetus, setting half an hour before
midnight. Farther over in western Gemini, Saturn
glides high in the sky (for mid-latitude northerners) across
the meridian to the south around 9 PM. The set is completed by
bright
Jupiter, second only to Venus, which can be found rising
between classical Leo and Virgo just as twilight ends, the
giant planet just a bit to the west of the Autumnal Equinox. Between about 7 and 9 PM all four
planets are in the sky at the same time, making for superb
telescopic viewing. A small telescope quickly reveals Jupiter's
cloud belts and satellites, Venus's
gibbous disk, and Saturn's glorious
rings plus its big moon, Titan
.
Several constellation groups around the sky are made of stars that
more or less belong together, not as real clusters, but as more
extended families (or "associations") whose members were born at
roughly the same time (in astronomical terms of course). To be
together still, they must be "young," and therefore must still
contain hot blue stars that give such constellations their sparkle.
Among them are groupings like Orion, Scorpius, and Centaurus, as well as several
others. This time of year, another goes flying overhead in early
northern evenings, Perseus, the
hero and rescuer of Andromeda, which is made of streams of stars, some of
which are the hottest in the naked-eye sky. Find the figure
directly to the west of Auriga,
the Charioteer, which itself stands to the north of Orion, the
Hunter the central figure of the northern winter sky.
