Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week. Rainbow's end...
Astronomy news for the week starting Friday, November 2, 2001.
The Moon fades this week from near full to its third quarter,
reaching the phase about the time of moonset the night of Wednesday
the 7th (or the morning of Thursday, the 8th). As it goes, it will
be seen to the west of Saturn the night of Friday, the 2nd, to the
east of it and closer the night of Saturday, the 3rd. The night of
Monday, the 5th, be sure to watch the Moon play closely with
Jupiter, our satellite only a couple degrees north of the giant
planet around midnight.
The two brightest planets in the sky, Venus and Jupiter, are
highlighted this week. (Yes, Mars can get brighter than Jupiter,
but for only a very short amount of time near its favorable
oppositions.) The morning of Friday, the 2nd, Venus stands four
degrees north of Spica, which the
Sun has just cleared, meaning that Venus is now rising rather late,
about 5 AM Standard Time, just after the birth of morning twilight.
On the same day, Jupiter becomes momentarily "stationary," that is,
it ceases its normal forward motion easterly through the stars, and
reverses into retrograde, as
the Earth prepares to come between it and the Sun. Two days later,
on the morning of Sunday, the 4th, Mars passes 2 degrees south of
Neptune, an event only visible if you have a telescope, Neptune
rather far below naked-eye brightness. Since Venus and Mercury
maintain their close connection this week, the two less than a
degree apart for most of this period, both actually are seen north
of Spica. Go look, and use Venus to find the smallest inner planet
(Mercury), which will be the brightest body close to bright Venus,
both notably bright in morning twilight.
With the Moon now gone from the evening sky, we can look again at
the stars. Even in early evening, the Great Square of Pegasus can be seen moving high in the southeastern
sky. The Square's northeastern star is part of both Pegasus and Andromeda, which climbs in
streams of stars to the northeast. In the middle of Andromeda, if
you have a dark sky, you might spot the fuzzy patch of the
Andromeda Nebula, which in the early twentieth century was
discovered to be a large nearby galaxy comparable to our own (our
200-billion-star assembly that makes the Milky Way). "Nearby" here
takes on a relative meaning, as this great spiral galaxy, also
called M 31, is two million light years away, the farthest thing
visible to the naked eye. Comparable in distance is another, M 33,
the great spiral galaxy in Triangulum, which under ideal circumstances (which
includes being young!) is also visible to the naked eye, though
just barely. The southern hemisphere contains two more naked-eye
galaxies, the Large and Small Magellanic Clouds in the
constellations Dorado (the
Swordfish) and Tucana (the Toucan),
these two requiring the observer's latitude to be well south of 20
degrees north latitude.
