Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
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Photo of the Week.. Venus and Jupiter appear just barely past
conjunction,
Jupiter the fainter of the two, on the morning of November 5, 2004.
Faint clouds that were
not visible to the eye enhance the scene. Watch a
three-day progression in the twilight morning sky.
Astronomy news for the week starting Friday, November 26, 2004.
Welcome to December, and while it is not yet astronomical winter,
we get the sense of its approach with the lowering of the Sun and
the
cooling of the air and land. During early fall, the Sun drops
quickly below the celestial equator.
As December begins, it is nearly 22 degrees to the south of it, and
is now not changing its north-south position much at all, just down
to 23.4 degrees south by December 21, hence the term "solstice,"
loosely meaning that the "Sun stands still" (in its north-south
motion), which gives our northern climes time to chill.
The week begins -- on Friday November 26th -- with the full
Moon. Since the Sun is approaching the Winter Solstice in Sagittarius, the full Moon is approaching the Summer Solstice in Gemini. By Monday the 29th, the waning gibbous will fall smack in the middle
of the classic constellation, while on Tuesday the 30th it finds
itself passing five degrees north of Saturn (which is now rising early, around 8 PM),
when the pair will make a nice triangle with Pollux. That same day the Moon is
also at apogee
, where it is farthest from the Earth. By the end of the week,
the Moon will be close to its third quarter (which will take place
on Saturday, December 4).
The morning sky continues to dominate the planetary scene. Jupiter, high to the southeast in Virgo as dawn brightens the sky,
leads the lot. Down and to the left in a long line find Spica (Virgo's luminary), then much
brighter Venus. Ending the stream just a bit below Venus, and much
fainter, is
Mars. As Venus prepares to pass to the north of the red
planet, the two draw close, the formal conjunction taking place the
morning of Sunday, December 5. The closeness is in line-of-sight
only of course, as Venus is inside the Earth's orbit and Mars is
outside of it. On December 1, Mars will be 1.7 times farther away
from us than Venus, in part accounting for its relative faintness.
(Being farther from the Sun, smaller, and rocky,
it also reflects less light than cloud-covered Venus).
The stars of northern autumn are slowly giving way to those of
winter. As the sky darkens look well to the south for a classic
fall star, Fomalhaut in Piscis Austrinus, the Southern Fish.
Below it, skimming the southern horizon (and lost to those much
north of 40 degrees north latitude) is the charming figure of Grus, the Crane, one of the few
"modern" constellations that sort of looks like what it represents.
To the north of Fomalhaut lie Aquarius, whose "Y"-shaped "Water Jar" straddles the
equator, and Pegasus, which
lies in the northern celestial hemisphere. As the evening moves
on, watch Orion climb the eastern
sky, followed by Sirius, which
rises about an hour after Saturn.
