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OverSky for March 2003: THE OLD, THE COLD AND THE DIRTY

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  • Erich Landstrom
    OverSky for March 2003: THE OLD, THE COLD AND THE DIRTY posted by Erich Landstrom, NASA JPL Solar System Educator While waiting one night for a meteor shower
    Message 1 of 1 , Mar 19, 2003
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      OverSky for March 2003: THE OLD, THE COLD AND THE
      posted by Erich Landstrom, NASA JPL Solar System

      While waiting one night for a meteor shower to peak,
      my friend shared a true story: a few years back, she
      was at her favorite stargazing, far from any light
      pollution, with a friend who hadn�t been under such
      dark skies in a while. He was excited to set up his
      telescope, but was annoyed at the one cloud that
      arched across the sky and refused to budge, blocking
      his view.

      We laughed at his frustration. That �cloud� wasn�t
      going anywhere any time in the next three billion
      years. That �cloud� was our Milky Way Galaxy, made up
      of millions of star systems, star clusters and
      nebulas. With so many stars, the Milky Way is over
      600,000 trillion miles wide. In fact, we are looking
      at the Milky Way from the inside because our solar
      system is a part of it. The light from so many stars
      so far spread out blends together. Our eyes are not
      sharp enough to pick out the individual stars,
      creating a faint, hazy appearance of a milk-white arch
      that rings around the sky. April is the last month to
      see the part of the Milky Way that stretches behind
      the winter constellations. Away from city lights under
      clear, dark skies, look to see it from the north in
      Perseus to the south in Pyxis, at the top of Taurus
      and the feet of Gemini and through Auriga, and between
      the winter triangle of Orion, Canis Major and Canis
      Minor. (Don�t worry if you miss it this month -- you
      have until the Milky Way collides with the Andromeda
      Galaxy 3 billion years from now. Even then, they merge
      slowly, over about 1 billion years, to form a
      non-spiral, elliptical galaxy.) But any bright light
      is enough to spoil your view and hide the galactic
      glory of the Milky Way.

      Our view of Milky Way Galaxy is blocked, though, by
      clouds of different type: intergalactic dust clouds.
      The light and more importantly the heat from distant
      suns are absorbed. Sensing that heat would allow
      astronomers to detect discs around other stars where
      planets may be forming, and provide valuable
      information about the early life of the universe.
      Nicknamed �the Old, the Cold, and the Dirty,�
      (referring to the oldest, coldest and most
      dust-obscured objects and processes in outer space)
      these are the targets of the Space Infrared Telescope
      Facility (SIRFT). Launch of SIRTF is scheduled for
      Tuesday, April 15, 2003, at 4:34:07 AM EDT from Cape
      Canaveral. SIRTF compliments the Hubble Space
      Telescope. Both belong to NASA's Great Observatories
      Program, each of which studies a different part of the
      spectrum; Hubble shoots pictures in visible light,
      Chandra takes X-ray images. Infrared light, invisible
      to the human eye, is typically absorbed by Earth's
      atmosphere and therefore ideal for an Earth-trailing
      space telescope. More information about the mission is
      available http://sirtf.caltech.edu/

      Old, cold and dirty also describes comets. Comets are
      interplanetary icebergs, and as a comet nears the Sun,
      dust mixed in with the ice is released. A meteor
      shower occurs as Earth transits through the tail of
      dusty debris dispersed by a comet. Before dawn on
      April 22nd the Lyrid meteor shower reaches its peak.
      The meteor shower is associated with the orbit of
      Comet Thatcher, which was first recorded in 687 B.C.
      In April 1803, 700 meteors per hour were seen.
      However, April 2003 is expect to be more modest, with
      a maximum of 15 meteors per hour
      Interested observers should look northeast after
      midnight. The Lyrid meteors are so named because they
      appear to emanate from the constellation of Lyra the
      Harp, home to the 3rd brightest star of the sky.
      Unfortunately the last quarter Moon rises at almost
      the same time as Lyra and its light will interfere
      with this year's display.

      LUNAR ALMANAC APRIL 2003 (All times are Eastern Time)
      April 1: New Moon
      April 4: Moon at apogee (406,209 km)
      April 7: Moon near Saturn
      April 9: First Quarter
      April 10: Moon near Jupiter
      April 16: Full Moon
      April 17: Moon at perigee (357,156 km)
      April 23: Last Quarter, Moon near Mars
      Tip: The full moon's diameter measures about 1/2 of
      one degree in the night sky.

      SOLAR ALMANAC April 2003 (All times are Eastern at the
      80 deg. N. longitude of West Palm Beach. Add 20
      minutes to each time for each 5� west.)
      Apr. 1: Sun Rise: 6:11 AM EST, Sun Set: 6:37 PM
      Apr. 14: Sun Rise: 6:57 AM EDT, Sun Set: 7:43 PM
      Apr. 28: Sun Rise: 6:44 AM EDT, Sun Set: 7:50 PM

      MERCURY materializes out of the dusk at sunset,
      shining at mag. -1.4 as April starts. But midmonth is
      has faded to mag. -0.5, but has climbed 20 degrees
      above the horizon. Using binoculars, look low in the
      west about 30 minutes after sunset.
      JUPITER (mag. -2.1) outshines the surrounding stars of
      Cancer, standing high and bright in the southwest in
      the early evening.
      SATURN (mag. +0.1) shines at the tips of Taurus and
      the toes of the Twins in the south after evening
      twilight, visible as the yellow �star� over Orion's
      head at sunset and setting around midnight.
      VENUS is so low in the pre-dawn sky that it is almost
      impossible to see until the end of April.
      MARS rises around 2 AM in the southeast. As it moves
      from Sagittarius into Capricornius, it continues to
      get brighter until it doubles in magnitude to +0.5.

      For news on space exploration with the "science giant"
      Erich Landstrom, listen to a live broadcast of SCIFI
      OVERDRIVE Monday mornings at www.scifioverdrive.com
      over the Internet! Our guests on Apr. 10 and 17 will
      talk about SIRTF and the Gravity Probe B. Free
      telescope viewing will be offered if the weather
      permits at the following dates and places: on
      Wednesday, April 9th at the main public library in
      West Palm Beach on Summit Blvd., on Thursday, April
      10th at the public library in West Boynton Beach on
      Jog Rd., and on Friday, April 18th at Sugar Sand
      Community Park at Military Trail & Palmetto Park Rd.
      in Boca Raton.

      Erich Landstrom, NASA JPL Solar System Educator
      Solar System Educators Program http://www.ssep.org
      [Hands-on teacher training workshops sharing NASA's
      missions of research, discovery and exploration!]

      Science fiction & science fact stranger than fiction.
      Listen Monday mornings on http://www.SCIFI-OVERDRIVE.com

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