|
FYI,
Cheers
@ji
Mars beams; Venus, Jupiter
rendezvous 3 neighbors go out of their way to
dazzle sky watchers David Perlman, Chronicle Science
Editor Three planets are putting on a
brilliant double feature in the skies over At On most nights, Venus and Jupiter
are the brightest of all planets in the solar system, but their star status is
not being completely eclipsed by Mars. As it turns out, they're putting on a
show of their own, giving the impression that they're drawing closer and closer
together, and by next Thursday, they will look to earthbound observers as if
they're almost kissing, astronomers say. The unusual sights are due to the
orbits of the planets in their regular procession around the sun. But even the
ordinary can offer rewards to anyone willing to look upward, said Andrew Fraknoi, chairman of the astronomy department at
"Astronomers like to provide
spectacles whenever they can," Fraknoi said, "and this
week the planets are gladly cooperating." Sky watchers, whether equipped
with binoculars, store-bought telescopes or observant eyes, will see Mars
shining brightly tonight as long as they're willing to wait until the hours
around "You won't be able to miss the
sight of Mars," Fraknoi said, "because the moon will
show you right where it is." And much earlier each evening in
the days ahead, Venus and Jupiter will appear strikingly near each other on
their way to their seeming rendezvous near the star Spica in the constellation Virgo, the Virgin. They can be
seen less than an hour after sunset and very low in the southwestern sky.
Each night, they will be moving
closer together, while Mars grows brighter. Mars is growing brighter now
because it's actually moving closer to Earth, the result of two planets
traveling on different paths around the sun and at different speeds.
Earth's orbit carries it closer to
the sun than Mars at a rate of speed more than 23,000 mph faster. Because of the
shorter, speedier orbit, Earth takes just 365 days to travel once around the
sun. Mars needs 687 Earth days to do the same thing. So roughly every two years,
Earth appears to catch up with Mars like two racers on concentric tracks, and
when that happens the positions of Earth and Mars appear to lie in a straight
line opposite the sun -- a lineup astronomers call opposition.
That opposition will not be
complete until Oct. 31, when the two planets will be only 43 million miles
apart. Rumors are flying around the
Internet that at the time of opposition Mars will be so big and bright that it
will rival the moon both in size and brilliance. The rumor is nonsense, said Fraknoi. It started with an anonymous
e-mail circulating among amateur astronomers that claims the planet is brighter
than it has been in 5,000 years and "will look as large as the full moon to the
naked eye.'' "Share this with your children and
grandchildren," the e-mail urges. "No one alive will ever see this again!"
Astronomers have no idea where the
e-mail originated and say Mars during this year's opposition will resemble
itself during the last opposition in August 2003, although perhaps not shining
quite as brightly. Two years ago, the planet appeared brighter than it had in
thousands of years, said Fraknoi, but it was still
only a tiny bright point in the sky; not a moonlike disk at all.
Mars was actually only 35 million
miles from Earth then -- and may not be closer to Earth than that for another
60,000 years, according to the calculations of NASA astronomers.
As for Venus and Jupiter, those
two planets are actually nowhere near each other. Venus, running around the sun
inside Earth's orbit, is roughly 106 million miles away these days, while
Jupiter is some 575 million miles away on an orbit far beyond Earth's path.
But the result is that Venus is
rapidly catching up with Jupiter on their orbital race, and by Sept. 1 the two
will appear to earthlings as though they are actually touching each other,
according to the calculations of the astronomers. E-mail David Perlman at
[EMAIL PROTECTED] -------------------------------------------------- Ikatan Alumni SMA Negeri 1 Bekasi, forum untuk menambah teman, saudara, sahabat, dan [.....]. Jika ingin berhenti menerima email dari sma1bks, kirim email ke [EMAIL PROTECTED] Ingin menerima email dari sma1bks, kirim email ke [EMAIL PROTECTED]
SPONSORED LINKS
YAHOO! GROUPS LINKS
|
