Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. The evening sky peeks through as
we fly between layers of clouds.
Astronomy news for the week starting Friday, July 11, 2003.
The Moon this week achieves its full
phase, when it is opposite the Sun in the sky, at around noon
on Saturday the 13th, when it is not visible in North America. The
night of Friday the 12th, the Moon will therefore rise a bit before
sunset, the night of Saturday the
13th a bit after, and since the difference is split, both risings
could be called "full moon."
As the Moon travels its orbit around the Earth, it will pass five
degrees to the south of Neptune the
night of Monday the 14th, then the same angle to the south of Uranus during the day of Wednesday the 16th, the dim
outer planets respectively in Capricornus and southwestern Aquarius. These are but a prelude to the passage of
the waning
gibbous Moon past Mars
the night of Wednesday the 16th, actually the morning of Thursday
the 17th, when the planet is just barely (from mid-latitudes) to
the north of the lunar disk. From southern climes, including
southern Florida, the Moon actually passes over, or occults, the
planet, a rare sight indeed. And one made more special -- even the
near misses are special -- as a result of Mars's unusual
brightness, the result of its growing proximity to Earth. Watch
for the red
planet to rise in the southeast around 11 PM, the time getting
ever earlier. The other naked-eye planets are effectively gone
from the sky, as they are too near the Sun -- in angle, not in
distance -- to be easily viewed. But with the Moon clearing out of
the way, the ever-present stars are there for us to admire.
Because the Earth orbits the Sun close to one degree per day (no
coincidence, as the degrees in a circle were meant to fit the
number of days in a year), the sky -- as viewed at the same time
each night -- slips to the west one degree per day (per night) as
well. Thus are the seasonal constellations. Now we see Scorpius passing by us far to the
south (for northerners) late in the evening, and the famed Big Dipper already to the west of
near-overhead. Directly beneath the curve of the Scorpion's tail
lies the constellation Ara, the
Altar, while directly north of it are the southern stars of Ophiuchus, the Serpent Bearer. The
modern boundaries of Ophiuchus actually extend across the ecliptic,
making it the "thirteenth" constellation of the Zodiac, the Sun
passing against it from November 30 to December 17, a period longer
than the duration of the Sun against the classical zodiacal
constellation of Scorpius, where the Sun lingers for a mere five
days. Nevertheless, Ophiuchus is not considered a part of zodiac,
just a kind of interloper.
