Skylights featured three times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
.
Photos of the Week.. Venus and Mars shine brightly
in the western sky the nights of March 9, 2004 (left) and March 11,
2004 (right). Venus is seen to the left of Aries, while Mars beneath the Pleiades star cluster of Taurus. Compare the photos to see the planets move
against the background stars.
Astronomy news for the week starting Friday, March 19, 2004.
We begin the week with the first day of northern hemisphere spring, at least if you are west of the
central time
zone (where it begins at 12:49 CST the morning of Saturday the
20th). On the west coast of the continental US, it begins at 10:49
PM PST the night of Friday the 19th (about as early as possible),
and on the east coast at 1:49 AM EST on the 20th. At these times,
the Sun will pass overhead at the equator, rise due east and set
due west, rise at the north pole, and set at the south pole.
Actually, because the Sun is a disk and because of refraction (bending) of
light by the Earth's atmosphere, anyone at the north pole would
have seen the Sun come up a couple days before the formal vernal equinox passage.
By coincidence, the Moon passes its new phase on the same day, the
evening of Saturday, the 20th. It will be possible, though
difficult, to see a thin crescent in western evening twilight by
the evening of Sunday, the 21st. By the evening of Monday the
22nd, however, the growing lunar crescent
will become obvious, glowing with soft earthlight. Look down and to the
right of the Moon on that night, and you might catch a glimpse of
Mercury just above the horizon. Binoculars will help.
Then we are in for a treat as the Moon visits the two planets that
bracket the Earth. Look to the east in the early evening of
Wednesday the 24th to see the Moon and
Venus as a classic pair, the brilliant planet just off the
crescent Moon's northern horn. Venus is so bright as to be visible
in daylight. Use the Moon near sundown, or in bright twilight, to
pick up the bright dot of Venus. The following night (Thursday the
25th), the Moon will make an even closer pass to the north of
Mars, just barely missing it. Those in the far north (the
Arctic and a bit south) can actually see the Moon occult, or cover,
the far more distant planet. By this time, Mars will have moved
well into Taurus to the east of
the Pleiades. Indeed, as we
begin the week, Mars is passing to the south of the star cluster,
making another fine sight to admire, and giving a good chance to
watch the planet's night-to-night motion.
While observing Mars and Venus, be sure too to catch the show being
put on by
Saturn and
Jupiter. As the sky darkens, Saturn is high and to the west of
nearly overhead in southern Gemini, the planet crossing the meridian near sunset.
To the east, Jupiter shines brightly in southern Leo, crossing the meridian shortly
before midnight.
Gemini, with Jupiter and its two bright stars, Castor and Pollux, really does serve as a center
of attention. To the northwest is Auriga, to the west Taurus, to the southwest Orion, to the southeast Canis Minor, to the east much dimmer
Cancer with its Beehive star cluster. To the
northeast is even dimmer, modern Lynx, the eponymous lynx.
