Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week.. Continuing our "thunderstorm-
from the air" series we see a close-up of anvilled clouds set
against the sky near sunset. Compare with the wider view.
Astronomy news for the week starting Friday, July 29, 2005.
The sky is a bit like people. At times it is wildly busy while at
other times it goes on vacation. Little seems to be happening this
week except that the ever-present Moon moves through its waning crescent phase towards new,
which it will pass the night of Thursday, August 4. Rising ever
later in the morning hours, it does not even make calls on any of
the planets. Lack of "events," however, hardly turns off the
beauty of the heavens, of a star-filled
sky, providing that you can find a dark enough location to see the
fainter ones.
Even in the brightest locations, however, you can still admire Venus
and
Jupiter, which now dominate the evening. As July turns to
August, Venus shines brilliantly in
western twilight, but still sets before twilight has finally faded
away, and in fact will continue to set before twilight ends
throughout the rest of August. High to the southwest as the sky
darkens lies Jupiter. Though bright, it pales next to Venus, which
is over six times brighter. Though Venus disappears quickly below
the horizon, Jupiter -- still in Virgo to the west of Spica -- lingers through the evening
until finally setting around 11 PM Daylight Time. For an hour the
sky is without bright planets. And then Mars
(now near the boundary where Pisces, Aries, and Cetus all meet) rises around
midnight. While brighter than all but the brightest stars, Mars shines at only
about a third of Jupiter's brilliance, its closeness to us offset
by its small size.
Mercury and Saturn
are too close to the Sun to be seen. Uranus
and
Neptune (respectively in Aquarius and Capricornus) are both up at sunset, but hardly make an
impact on the nightly sky. Uranus is near the limit of human
vision, while the viewing of Neptune requires a small telescope.
And forget seeing Pluto
, which requires a fairly large one. Because of its large
orbital tilt relative to the rest of the planetary system, the
little planet can be found well off the Sun's ecliptic path, and now lies near
the boundary of Ophiuchus and
the eastern half of Serpens
(Serpens Cauda, the head of the celestial serpent).
Though it has moved well into the western sky, there is still
plenty of opportunity to admire the brightest star of the northern
hemisphere, Arcturus of Bootes (the Herdsman), which just
barely beats out Vega (which is high
in the east just after sundown). Just draw a line that follows the
curve of the Big Dipper's handle
to the south and it will pass first through the orange-colored star
and then through Spica, to the
south of which winds the tail of Hydra, the Water Serpent.
