Skylights featured five times on Earth Science
Picture of the Day: 1
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Photo of the Week.Canis
Major, Orion's Greater
Hunting Dog, bounds through the forested sky, its great star Sirius sending out a mighty glow.
Astronomy news for the week starting Friday, March 10, 2006.
Read A
Minute with Jim Kaler, a brief interview on the outer bodies of
the Solar System that appears on the U of I home page.
We begin the week with the Moon in its waxing
gibbous phase moving toward full, which it will reach the night
of Tuesday, March 14, about the time of Moonrise in North America -
- or, since the full Moon is opposite the Sun, also about the time
of sunset. The night of Friday the 10th finds the Moon to the
northeast of Saturn;
the night of Saturday the 11th it will be to the west of Regulus, the star at the end of the
"Sickle" of Leo. On the night of
the full phase, the Moon will appear south of Denebola (also in Leo) as it enters
western Virgo rather well to the
west of Spica, which (in the waning
gibbous phase) it will pass the morning of Friday the 17th (and
will actually occult for those living in Hawaii).
Two days before full, the Moon will pass apogee,
where it is farthest from the Earth in its monthly round. The full
Moon actually rises in North America during the ending stage of a
penumbral eclipse, in which the Moon is passing out
of the penumbra of the Earth's shadow. The penumbra is the region
of partial shadow; were one on the Moon, one would see the Earth
only partially blocking the Sun. Do not confuse with a "partial
eclipse" in which part of the Moon enters the full shadow of the
Earth. Penumbral eclipses are barely visible, and this one for us
will not be sensible at all, so just admire the Moonrise.
Mercury is
now completely gone from the visible sky, as it passes inferior
conjunction with the Sun (more or less between us and the Sun) on
Saturday the 11th. Saturn, still
in Cancer, lies high to the south
in mid-evening. Mars, moving
quickly through Taurus, will
pass seven degrees to the north of Aldebaran on Friday the 10th,
giving us for several days a fine chance to compare similarly-
colored celestial jewels, the red planet not setting until somewhat
after midnight. Jupiter's
southeasterly rise around 10:30 PM will then give us three planets to
admire. The planetary giant then transits the meridian about 4 AM
about as brilliant Venus
rises and Saturn sets.
March is a fine time to pay attention to Orion's two hunting dogs, Canis Major and Canis
Minor, which respectively lie to the southeast and east of
Orion, and which are graced by two bright stars, Sirius (the brightest in the sky) and
eighth-ranking Procyon.
Curiously, the luminaries of the two dogs are both attended to by
orbiting white
dwarf stars, old dead nuclear-fusing cores that once far
outshined their mates and that are now shrunk to the size of Earth.
The two bright stars are connected as well through one of the great
cross-constellation figures of the sky, as with Betelgeuse they make the Winter Triangle.
