Photo of the Week. It came from outer space. Once
part of the core of an asteroid broken up in an ancient collision
(and then further broken by a violent passage through the Earth's atmosphere),
this 16 kilogram (35 lb) piece of Africa's Gibeon iron meteorite is
part of the just-opened Goose Kaler Memorial Meteorite Collection
at Staerkel Planetarium in Champaign, IL. Known to the locals of
what is now Namibia, the vast numbers of Gibeon fragments were first found
by westerners around 1836. There is no record of its fall.
Astronomy news for the week starting Friday, April 12, 2013.
Nearly the whole week is occupied with the waxing crescent Moon, which will range from
very thin and not far from the horizon the evening of Friday, April
12th (as our week opens), to first
quarter, which takes place on the morning of Thursday the 18th.
By the time the Moon is seen that afternoon and evening, it will be
very slightly in the waxing gibbous
phase. Can you tell? On Monday the 15th our companion goes
through its
apogee, where it is farthest from the Earth on its modestly
elliptical path.
Early in the week, the crescent will present a series of fine
sights as it approaches and passes through Taurus. The twilit evening of Friday the 12th, the
setting Moon will lie below the Pleiades, while the following evening look for it
passing between the Pleiades and the Hyades clusters with the first magnitude star Aldebaran up and to the left and
bright Jupiter above. The night of Sunday the 14th will feature
the growing crescent close to the giant planet (at least as seen
from Earth). And the good views just continue when the Moon passes
through the next constellation of
the Zodiac, Gemini, and on the evening of
Wednesday the 17th places itself to the south of Castor and Pollux.
The three terrestrial planets are all pretty much out of sight. Mercury rises in bright morning twilight. Venus has just passed superior conjunction with the
Sun (on the far side of it) and will not be readily visible in
evening twilight for some time yet without special effort, a flat
horizon, and binoculars. And
Mars is really gone, as it passes through conjunction with the
Sun on Wednesday the 17th, and will remain for a time invisible in
morning twilight. That leaves us with the two giants of the Solar
System. Now exclusively an evening object seen to the west as
darkness closes in, Jupiter disappears below the northwestern
horizon around 11:30 PM Daylight Time, while in the other
direction, Saturn comes up
above the southeastern horizon when the sky is still in evening's
light. Look for it to cross the meridian to the south about 2 AM. At the
far end of the Solar System,
http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-plut
o-k4.html">Pluto begins its very slow retrograde motion (westerly against the stars of
northern Sagittarius) as our week
opens.
In late evening, the Bowl of the Big
Dipper in Ursa Major passes
high, nearly overhead. To the south (and a bit west) of it roars
Leo the mighty Lion, notable for the Sickle-shaped
curve of stars that ends in Regulus and marks his head (modern
little Leo Minor on his back).
South (and again a bit west) of the Sickle, find the luminary of Hydra (the Water Serpent), second
magnitude Alphard, while skimming
the southern horizon will be Vela,
the Sails of the Ship Argo.
