Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. A "sub-sundog" appears in clouds
below a speeding aircraft, caused by sunlight refracting in ice
crytals.
Astronomy news for the week starting Friday, August 1, 2003.
The Moon
waxes through its gibbous phase the
early part of the week, and passes full the night of Monday, the
11th, just about midnight when the Moon is highest in the sky in
North America, not that it will be all the high, as with the Sun
crossing into western Leo,
the full Moon will be well to the south
in Capricornus. On Monday the 11th,
the Moon will glide south of
Neptune, while the night of Tuesday the 12th, it will pass
south of
Uranus, then during the day on Wednesday the 13th (for the
Americas) to the north of Mars
. The night of Tuesday the 12th, look for the Moon to the east
of the red planet (which is now rising around 9:30 PM Daylight
Time), while the night of Wednesday the 13th sees the Moon to the
northeast of the planet.
Mars,
amazing Mars, the most earthlike of all planets, is getting ever
closer to its rendezvous with Earth on August 27-28, when it will
be closer to us, 34,646,400 miles, than any time within about the
last 50,000 years. As a result, it will be at its very brightest,
exceeding
Jupiter in apparent luminosity, its reddish color brilliant
against the black of night. However, we need to keep some
perspective. Because of the eccentricity of its orbit, Mars goes
through a 17 year cycle of oppositions with the Sun, which are
about two years apart. When an opposition occurs when Mars is
farthest from the Sun, at its aphelion, it is double its distance
than when it is at perihelion (the latter called a "favorable
opposition.") Mars is simply having an especially good favorable
opposition, but one that is not all THAT much better than many
others we have had. Its special closeness is more a curiosity than
anything very noticeable. While the planet will be bright and
beautiful (as it is now), it will not be so overwhelming as perhaps
anticipated by many. Just enjoy a special time, and if you can,
admire its still-small disk in a telescope, which will allow a view
of some dark markings and perhaps a polar
cap.
Mercury,
ignored in news of Mars, makes something of an appearance in the
evening sky, as it reaches greatest eastern elongation with the Sun
on Thursday, the 14th. The low angle of the ecliptic to the
horizon will make the planet difficult to see, however. Saturn is
a bit better, the ringed planet now rising about 3 AM Daylight
Time.
August is the traditional best month for meteors, as the Perseids peak the morning of Wednesday, the 13th.
The periodic meteor shower, which brings one to two meteors per
minute to the morning sky, will be largely destroyed this year by
light from the nearly full Moon. At least one can admire Perseus climbing in the northeast. In
the evening, cast your eye toward striking Scorpius (the Scorpion), with its curved tail and
bright Antares, the constellation
crossing the meridian to the south as evening descends. To the
southwest of it is Lupus, the Wolf,
and below it -- if you are far enough south -- you can see the
stars of Ara, the Altar.
