bcg@ncs-med.UUCP (Brian C. Grande) (11/25/85)
Hi! I downloaed this from the local L5 modem (612-920-5566) and am
just passing it along. -brian 8')
Greetings, this is Minnesota Starwatch for December 1985.
Comet Halley is still approaching the Sun this month. With a good dark
site, far from the city lights, you should be able to see it in binoculars.
You will need a star chart to know where to look, and a bit of patience.
Halley will be visible in the eastern sky for a few hours after sunset each
night in the constellations of Pisces, and later, Aquarius. The darkest
evenings, without any moon, will last until mid-month.
New moon this month is December 11th. The next two nights are good times
to look for the Geminid meteor showers as well as Comet Halley.
Jupiter is the lone planet in the evening sky, shining brightly not far
above the southern horizon. Pre-dawn viewers can find Mars high in the eastern
sky, while Venus will disappear below the eastern horizon early in the month.
In December in Minnesota, the dwindling sunlight is on everyone's mind.
December 21st is the winter solstice, when the noon-day sun will creep up only
22 degrees from the horizon around noon, and we will have less than 9 hours of
daylight. This low angle in the sky, and the short daylight hours, mean that
the northern hemisphere receives less solar heat, giving us winter. Like a hot
rock pulled out of a fire, the North will continue to cool, for the next two
months. To get a feel for how much heat the Earth receives from the Sun, think
about the roof of your house at the height of summer. If you put 1
hundred-watt light bulb on every square foot of roof, that would produce about
as much heat as the sun does. Of course, cloudy skies, seasons and the sun
rising and setting take their toll. Taking a wider view, we find that the
overall temperature of the Earth is regulated by the Sun. We continually get
heat from the Sun, and re-radiate it back into space. This balanced process
leads to an average temperature on Earth of about 70 degrees F.
However, it also depends on our atmosphere acting like a blanket; without it,
our average temperature would be below zero. That's a nice cheery thought, for
a Minnesota winter.
The current show at the Minneapolis Planetarium is "The Christmas Sky."
Show times are Saturday at 11:00, 2:00, and 3:00 and Sunday at 2:00 and 3:00.
The Planetarium is located in the main Public Library, 300 Nicollet Mall. For
more information, call 372-6644.
This has been Minnesota Starwatch, produced by the University of Minnesota
Astronomy Department in cooperation with WCCO Weather Center.
--
Brian Grande ihnp4!umn-cs!ncs-med!bcg
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