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The Sky Tonight

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  • val2160
    From AOL News: Look to Sky for Spectacular Sight Monday By Joe Rao Space.com (Nov. 29) - Every once in a while, something will appear in the night sky that
    Message 1 of 1 , Dec 1, 2008
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      From AOL News:

      Look to Sky for Spectacular Sight Monday
      By Joe Rao
      (Nov. 29) - Every once in a while, something will appear in the night
      sky that will attract the attention of even those who normally don't
      bother looking up. It's likely to be that way on Monday evening, Dec. 1.
      A slender crescent moon, just 15-percent illuminated, will appear in
      very close proximity to the two brightest planets in our sky, Venus
      and Jupiter.
      People who are unaware or have no advance notice will almost certainly
      wonder, as they cast a casual glance toward the moon on that night,
      what those two "large silvery stars" happen to be? Sometimes, such an
      occasion brings with it a sudden spike of phone calls to local
      planetariums, weather offices and even police precincts. Not a few of
      these calls excitedly inquire about "the UFOs" that are hovering in
      the vicinity of our natural satellite.
      A Rare Alignment
      On Monday night, the three brightest objects in the night sky --
      Jupiter, Venus and the moon -- will line up close together in a
      spectacular sight, closer than they will appear until 2052. One expert
      said the alignment, captured here in 2004, will "be a head-turner."
      Click through the rest of the gallery for some amazing space images.
      (Note: Please disable your pop-up blocker)
      Very Bright Objects
      Venus has adorned the southwestern twilight sky since late August. No
      other star or planet can come close to matching Venus in brilliance.
      During World War II, aircraft spotters sometimes mistook Venus for an
      enemy airplane. There were even cases in which Venus drew antiaircraft
      This winter, Venus is the unrivaled evening star that will soar from
      excellent to magnificent prominence in the southwest at nightfall. The
      interval by which it follows the Sun will increase from nearly three
      hours on Dec. 1 to almost four hours by Jan. 1. It's probably the
      first "star" you'll see coming out after sunset. In fact, if the air
      is very clear and the sky a good, deep blue, try looking for Venus
      shortly before sunset.
      Jupiter starts December just above Venus and is moving in the opposite
      direction, dropping progressively lower each evening. By month's end
      Jupiter meets up with another planet – Mercury – but by then Jupiter
      is also descending deep into the glow of sunset. In January, Jupiter
      will be too close to the Sun to see; it's in conjunction with the Sun
      on Jan. 24.
      Earthlit Ball
      A very close conjunction of the crescent moon and a bright star or
      planet can be an awe-inspiring naked-eye spectacle. The English poet,
      critic and philosopher, Samuel Taylor Coleridge (1772-1834) used just
      such a celestial sight as an ominous portent in his epic, "The Rime of
      the Ancient Mariner." In addition, there are juxtaposed crescent moon
      and star symbols that have appeared on the flags of many nations,
      including Turkey, Pakistan, Malaysia, Algeria, Mauritania, and Tunisia.
      Also on Monday evening, you may be able to see the full globe of the
      moon, its darkened portion glowing with a bluish-gray hue interposed
      between the sunlit crescent and not much darker sky. This vision is
      sometimes called "the old moon in the young moon's arms." Leonardo da
      Vinci (1452-1519) was the first to recognize it as what we now call
      As seen from the moon, the Earth would loom in the sky some 3.7 times
      larger than the moon does for us. In addition, the land masses, the
      oceans and clouds make the Earth a far better reflector of sunlight as
      compared to the moon. In fact, the Earth's reflectivity varies as
      clouds, which appear far more brilliant than the land and seas, cover
      greater or lesser parts of the visible hemisphere. The result is that
      the Earth shines between 45 and 100 times more brightly than the moon.
      The Earth also goes through phases, just as the moon does for us,
      although they are opposite from what we see from Earth. The term for
      this is called "complementary phases." On Nov. 27, for example, there
      was a new moon for us, but as seen from the surface of the moon that
      day, there appeared in the lunar sky a brilliant full Earth. A few
      nights later, as the sliver of a crescent moon begins to appear in our
      western twilight sky, its entire globe may be glimpsed.

      Sunlight is responsible for the slender crescent, yet the remainder of
      the moon appears to shine with a dim blush-gray tone. That part is not
      receiving sunlight, but shines by virtue of reflected earthlight: the
      nearly full Earth illuminating the otherwise dark lunar landscape. So
      earthshine is really sunlight which is reflected off Earth to the moon
      and then reflected back to Earth.
      Keeping It All in Perspective
      Keep in mind that this head-turning display of three celestial objects
      crowded together will be merely an illusion of perspective: the moon
      will be only about 251,400 miles from Earth, while Venus is nearly 371
      times farther away, at 93.2 million miles. Meanwhile, Jupiter is
      almost 2,150 times farther away than our natural satellite at 540.3
      million miles.
      Those using binoculars or a small telescope will certainly enjoy the
      almost three-dimensional aspect of the moon, but Venus will be rather
      disappointing appearing only as a brilliant blob of light, for right
      now, it's a small, featureless gibbous disk. That will change in the
      coming weeks, however, as Venus approaches Earth and the angle it
      makes between us and the Sun allows it to evolve into a "half-moon"
      phase in mid January, and a lovely crescent phase of its own during
      the latter part of February and March.
      Jupiter on the other hand is a far more pleasing sight with its
      relatively large disk, cloud bands and its retinue of bright Galilean
      satellites. All four will be in view on Monday evening, with Callisto
      sitting alone on one side of Jupiter, Ganymede, Io and Europa will be
      on the other side. Io and Europa will in fact, appear very close to
      each other, separated by only about one-sixth the apparent width of
      Venus 'Eclipse' for Europe
      As beautiful as the view of Venus, Jupiter and the moon will be from
      North America, an even more spectacular sight awaits those living in
      parts of Western Europe where the moon will pass in front of Venus.
      Astronomers refer to this phenomenon as an "occultation," taken from
      the Latin word occultare, which means "to conceal." This eye-catching
      sight will be visible in complete darkness across much of Eastern
      Europe. Farther west, Venus will disappear behind the dark part of the
      moon either during evening twilight or just before the Sun sets. When
      Venus emerges, it will look like a brightening jewel on the slender
      lunar crescent. For virtually all of Europe, the Sun will have set by
      then, the exception being southern Portugal (including Lisbon).
      Such favorable circumstances are quite rare for any given location.
      For example, the last time London was treated to such a favorably
      placed Venus occultation such was back on October 7, 1961. And after
      2008, there will not be another similarly favorable Venus occultation
      for the United Kingdom until January 10, 2032. So be sure to make the
      most of this upcoming opportunity. More detailed information,
      including maps of the occultation zone, as well as times for dozens of
      European cities, are here
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