Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. Darkening clouds wrap around the
Sun, bringing rain to the lands below.
Astronomy news for the week starting Friday, April 9, 2004.
The Moon passes its last quarter
(which refers to the quartering of the orbit counting from new
Moon) the night of Sunday, April 11, somewhat before Moonrise in
North America. Note how the third quarter faces to the east,
against the rising of the Sun, whereas the first quarter faces west
toward the solar setting point. On Tuesday the 16th the waning crescent Moon passes well
south of Neptune in Capricornus, and a day later south of
Uranus,
which is now ensconced in southern Aquarius. These two outer large, but faint, planets
are slowly drawing apart, Uranus with an 84 year period around the
Sun, Neptune taking all of 164 years. Neptune has yet to make a
full circuit since its discovery in 1846.
Vastly brighter are Venus
through Saturn.
Of them all, brilliant Venus, high in the western sky in early
evening, tops them, not setting until after 11:30 Daylight Time
(where it will stay through the whole month). Venus is now passing
to the north of the Hyades in Taurus, just to the west of Mars (in
central Taurus), which sets less than half an hour after its
brighter neighbor. In the other direction, in the east after
sundown, is Jupiter,
second only to Venus in brightness. By 10:30 PM Daylight Time, the
giant planet is high in the south as it transits the meridian. In
between Venus and Jupiter, Saturn continues to ply southern Gemini.
As summer approaches, Ursa Major,
with its Big Dipper, begins to
glide overhead as it chases obscure constellations like Lynx (the Lynx) and Camelopardalis (the Giraffe) to the
west, the latter two a pair of "modern constellations." The deep
southern hemisphere, far out of sight from the northern lands where
the old constellations were invented, is replete with "moderns."
Even the famed Southern Cross (Crux) is one. Others like Mensa (the Table) and Volans (the Flying Fish) are nearly unknown by those
living in the north. Volans, made of modest stars, lies only 20
degrees from the southern pole, and is one of the three fishy
constellations, the others the classic Pisces (the Fishes) and Piscis Austrinus, the southern Fish. The latter
contains Fomalhaut, "the Fish's
Mouth," into which Aquarius pours the water from his "Water Jar."
Back to the north country, watch for Arcturus climbing the eastern sky,
a sure harbinger of warmer weather, this star marginally the
brightest of the northern hemisphere. It is followed in brightness
by Vega in Lyra and Capella in
Auriga, which is now escaping
into the northwest.
