Skylights featured five times on Earth Science
Picture of the Day: 1
Photo of the Week. Gemini in bronze decorates the
outside of the original Adler Planetarium.
Astronomy news for the week starting Friday, November 16, 2001.
The Moon first becomes visible tonight, Friday the 16th, as it
clears its new phase and climbs the western evening sky as a waxing
crescent, Earthlight on the lunar
nighttime side seen in all its glory. The crescent phase ends with
the first quarter the night of Thursday, November 22, to help those
in the US celebrate Thanksgiving. The night before, Wednesday
November 21, the near-quarter will pass three degrees south of
still-bright Mars, which continues to hang low in the evening
southwest within the confines of Capricornus between much dimmer
Uranus and Neptune.
The giant planets creep ever more into the evening sky. Saturn,
making a fine configuration with Aldebaran and the Hyades in Taurus, now rises in twilight shortly after sundown.
Jupiter, beautiful in eastern Gemini, unmistakable comes up about two hours later
(about the same time as Betelgeuse in Orion), after which it dominates the
heavens as befits the king of the planets. However, Venus, because
of its proximity and reflective cloud cover the brightest of all
the planets, is becoming increasingly difficult to see, as it is
now rising rather well after morning twilight begins. Look for it
low on the eastern horizon before sunrise.
But planets take second rank this week beneath the banner of the
Leonids, one of the great meteor showers of all time. Because of
its reliable annual nature, the Perseids of August are better
known. Usually the Leonids, produced by dusty debris flaked off
Comet Temple-Tuttle, are not very impressive. However, following
along behind the 33-year-period comet are concentrated chunks of
the stuff. If the Earth passes through one of them, we get not
just a meteor shower but a meteor STORM. In 1833 the count was
tens of thousands of meteors per hour. The 1967 storm was
spectacular. Over the past two years we have witnessed fine
showers with many big fireball meteors, but no storm. Perhaps this
will be the year. Whether so or not, it surely is worth the look.
The best time is predicted to be on the morning of Sunday, November
18 shortly before dawn, around 4 AM Central Time. Meteor showers
seem to emanate from their own particular "radiants" in the sky, a
perspective effect, as the paths of the particles that make them
are really on parallel tracks. The position of any radiant depends
on the motion of the Earth and of the particles at the time we pass
through the swarm. The Perseids seem to come out of Perseus, the Leonids from the
Sickle of Leo, which will be well-
up in the eastern sky.
Even if the big event does not occur, you can at least admire the
winter stars hurrying off to the west, Orion prominent, brilliant
Sirius lighting the southern sky.