This
month’s star chart shows a nice alignment of Saturn, Jupiter, and Mars
in the west at 8:00 PM on April 1, the night of our scheduled star party.
Notice the range of magnitudes listed beside the planets. All three
planets are rather low in the sky, Saturn about 21 deg above the horizon,
Jupiter and Mars about 15 and 13 deg, respectively. Over the next
month or so, these planets will gradually drop below the western edge of
our night sky.
Saturn
is now nearly 1 billion miles from the earth, Jupiter about 500 million
and Mars about 200 million. The changing distances of the planets
from the earth is the major factor in their changing magnitudes.
Another
kind of alignment will occur on May 5 (see the article in Sky & Telescope,
April, p. 93). If we could look down on the solar system from above
the north, we would see the earth, moon, and Pluto lying nearly in a straight
line on the same side of the sun. On the other side of the sun, Mercury,
Venus, Mars, Jupiter, and Saturn lie within about 60 deg, measured from
the sun. Uranus and Neptune lie about 90 deg away from the alignment
of the other planets.
Astrologers
and other misguided folk have read portents of disaster into planetary
alignments. Several years ago, Indian astrologers spoke of the “Jupiter
effect,” predicting earthquakes, tidal waves, and other assorted disasters
arising from an alignment of the planets within about 90 deg. Indeed,
astronomers predicted an increase of 1 millimeter (the thickness of a dime)
in our high tides. Somehow, we survived! But the real threats
of earth-crossing asteroids, and perhaps comets (remember Shoemaker-Levy
9?), are quite another matter. Stay tuned!
You can print a copy of this star chart so you
can take it outside.
