Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. A huge summer cloud billows to
the sky.
Astronomy news for the week starting Friday, July 25, 2003.
The Moon
wanes in its crescent phase the early part of the week, passing new
the night of Monday, July 28, about midnight in the Americas. The
slim waxing crescent will be technically visible in the west-
northwest the night of Tuesday the 29th, but very difficult to see;
the following night, however, it will be obvious. Watch the phase
grow, the nighttime lunar side bathed in Earthlight, over the following
couple of days.
Many are the pairings of the Moon and planets, though most are
difficult to see. The night of Saturday, the 26th, the Moon passes
the north of Saturn, this one visible as the ringed planet is now
rising shortly before dawn begins. The morning of the 26th, the
Moon will be a bit to the west of Saturn, the following morning a
bit to the east. Following new, the Moon then passes
Jupiter and then Mercury on
Wednesday, the 30th, neither planet up high enough in evening
twilight to see without special effort. That same day, Mercury
makes a very close pass to the north of the star Regulus. More intriguing perhaps,
Jupiter and Mercury are in conjunction with each other, Mercury
only half a degree to the north of the giant planet, as our week
begins, the evening of Friday the 25th.
With these events and planets too close to the Sun for easy viewing,
the week belongs to reddish Mars,
which now rises brilliantly, brighter than the brightest star,
around 10:30 PM Daylight Time. Closing in on its opposition to the
Sun on August 28, the planet begins its retrograde -- westerly -- motion against the stars of
southern Aquarius on Wednesday, the
30th. Watch as it backtracks, and quickly rises ever earlier in
the east-southeast.
This is the season now to look to the east in early evening, to
admire the great Summer
Triangle marked at its western apex by Vega (in Lyra, the Lyre), at its southern by Altair (in Aquila, the Eagle), and at its eastern by Deneb (in Cygnus, the Swan). Though Deneb, at the tail of the
celestial Swan, seems the faintest of the three, it is by far the
most distant, and therefore by far intrinsically the most luminous,
indeed, it is one of the more luminous stars in our entire Galaxy, first
magnitude even though as much as 2600 light years away, the light
you see having left the star as early as 500 BC. By contrast, Vega
is a mere 25 light years distant, the three-dimensional view of the
sky difficult for anyone to really imagine. In a dark sky away
from city lights, with no Moon, the Milky Way
glows brilliantly as it flows from Cygnus through Aquila and down
to Sagittarius and the southern
horizon.
