Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photo of the Week.. As the Sun sets over the Pacific
Ocean, a distant freighter appears "hull down" on the horizon, its
lower hull hidden around the curvature of the Earth. The effect is
one of the classic "proofs" that the Earth is a sphere. See the whole set of three pictures to watch the
Sun set and the ship sail north. Then expand them to see the panoramic view.
Astronomy news for the week starting Friday, April 16, 2004.
The Moon starts the week in its
waning crescent phase, and then quickly passes new on Monday
the 19th. On that day, it will also pass nearly in front of the
Sun to produce a partial solar eclipse, unfortunately one that will be
visible only in the South Atlantic, part of
Antarctica, and southern Africa. If the Moon is near to crossing
the ecliptic (the apparent path of the Sun) at new, it is likely
also to be crossing it at the full phase either before or after the
solar eclipse to produce an eclipse of the Moon. One will indeed
take place on May 5, but again one not visible in North
America. The Moon then takes aim on
Venus. Watch for a fine configuration between the two the
evening of Thursday the 22nd, when the growing crescent will appear
immediately down from the brilliant planet. Earthlight on the lunar nighttime
side will add to the show.
On Friday the 16th, Venus will pass several degrees to the north of
Aldebaran (and the Hyades) in Taurus, while on the same day the other "inferior
planet," Mercury, passes
its inferior conjunction with the Sun, when it is more or less
between us and the Sun and completely invisible. Look up and to
the left of Venus to find much dimmer Mars -- also in
Taurus -- as the two draw closer and closer together. Proceeding
to the east of Mars (but still in the western sky), find slowly
moving Saturn in
southern Gemini, and then
further over Jupiter
(exceeded in brightness only by Venus) in southern Leo. Saturn now sets shortly after 1
AM Daylight Time, while Jupiter crosses the meridian to the south
a little over an hour and a half after the end of twilight.
The week is highlighted by one of the year's more prominent meteor
showers, the
Lyrids, which appear to come out of the constellation Lyra and peak the morning of
Thursday, the 22nd. The debris of the Comet of 1861, the Lyrids
typically produce about a dozen meteors per hour in a dark sky,
which we will have with the Moon well out of the way.
The northern hemisphere is now well into "Dipper Season." In early
evening, the Big Dipper of Ursa Major, with its prominent seven
stars, is crossing the meridian high, nearly overhead. At the same
time, the Little Dipper of Ursa
Minor is sticking out to the right of Polaris and the North Celestial
Pole, around which the sky's stars appear to go as the Earth
rotates below. In contrast to its bigger cousin, the entire Little
Dipper is hard to see. In the lights of town only Polaris and the
two front bowl stars (Kochab and
Pherkad) are readily visible,
while the others in between all require a fairly dark sky. Wrapped
around the Little Dipper to the right in early evening is the
stream of stars that make Draco,
the Dragon. Then look to the south of the Big Dipper to find the
lovely stellar spattering that makes Coma Berenices, one of the sky's fine naked-eye clusters.
