Skylights featured five times on Earth Science
Picture of the Day: 1
Photo of the Week. Blue sky with corn.
Astronomy news for the week starting Friday, November 30, 2001.
The beginning of the week sees the Moon at full phase, which is
reached shortly before moonrise the night of Friday, November 30,
in North America. That night the Moon will therefore rise in
twilight just after sundown. Since the Sun is now not far from the
winter solstice in Sagittarius, the oppositely-positioned
full Moon will be just shy of the summer solstice in Gemini, and will therefore be moving against the stars
of Taurus, where we now find
Saturn. The result will be a special treat, an occultation of the
ringed planet in which the Moon will appear to pass across it. The
occultation will be observable shortly after Moonrise through most
of the US and Canada, with the northwest unfortunately left out,
the Moon hiding Saturn for about an hour. Binoculars will help.
Begin looking shortly after 6 PM Central Time. For the remainder
of the evening, the near-full Moon will appear just to the east of
Saturn. The night of Sunday, December 2, the Moon will then be
just to the west of Jupiter in Gemini, the night of Monday the 3rd,
just to the east of it.
That the Moon is covering Saturn when it is close to full phase
means that Saturn is also opposite the Sun, and sure enough, the
planet passes through formal opposition to the Sun on Monday, Dec.
3. That night it will rise at sunset, set at sunrise, and cross
the meridian high to the south at midnight. The planet is now
glorious in a telescope, its rings nearly fully "open," that is,
tilted toward us to greatest advantage. Even a small telescope
quickly reveals Titan, Saturn's largest moon, which is roughly the
size of the planet Mercury, as a satellite second in size only to
Jupiter's Ganymede, and the only satellite with a thick
The tag ends of the planetary system rendezvous with the Sun, at
least from the perspective of Earth. Mercury passes through
superior conjunction with the Sun on Tuesday, December 4, while
Pluto is in conjunction on Thursday, the 6th. Of course that is
only a line-of-sight coincidence. In reality, Mercury will be 40
million miles (nearly 70 million kilometers) the other side of the
Sun, while Pluto will be an astounding 2.8 billion miles (4.5
billion kilometers) to the other side. Pluto is so far away that
if you were to try a telephone conversation with a pretend
astronaut (a very brave one we might add), it would take nearly
four and a half hours for the radio signal -- moving at the speed
of light -- just to get there. Then you would have another 4.4
hours to wait for an answer.
The remaining outer planets, Uranus and Neptune, still both reside
in Capricornus, which is now seen
in the southwest in early evening and near invisible in bright
moonlight. While Jupiter takes 12 years to pass through the
constellations of the Zodiac and Saturn 29.5 years, these two
respectively take 84 and 165 years, and linger within their current
constellations of residence for a considerable time.