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Fwd = Planets for Dessert (full story)

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  • Frits Westra
    Forwarded by: fwestra@hetnet.nl URL: http://www.spacescience.com/headlines/y2000/ast30mar_1m.htm Original Date: Sat, 1 Apr 2000 19:18:26
    Message 1 of 1 , Apr 2, 2000
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      Forwarded by: fwestra@...
      URL: http://www.spacescience.com/headlines/y2000/ast30mar_1m.htm
      Original Date: Sat, 1 Apr 2000 19:18:26 +0200

      ========================== Forwarded message begins ======================

      Planets for Dessert

      On April 6, 2000, Jupiter, Saturn, Mars and the Moon will put on a
      delightful after-dinner sky show.

      [bryce_tmp.gif] March 30, 2000 -- Next Thursday, April 6, three
      planets and the thin crescent Moon are going to put on a memorable sky
      show when the quartet converge inside a circle just 9 degrees across.
      "It's going to be beautiful," says Vince Huegele, a researcher at the
      NASA/Marshall Space Flight Center. "And best of all, you won't need a
      telescope to see it, just your naked eye."
      Right: [2]Duane Hilton's rendering of the April 6 planetary
      get-together as seen above Bryce Canyon in Utah.
      To admire the display, simply go outside after dinner on April 6 and
      look toward the southwest sky. Around 8 p.m. local daylight savings
      time the slender crescent moon will be easy to spot about 30 degrees
      above the horizon. The brightest nearby "star" will be Jupiter. At
      magnitude -2.1, the giant planet is 8 times brighter than Saturn,
      which glows pale yellow less than 3 degrees west of the Moon. Mars
      will lie a scant 1.1 degrees north of Jupiter. The red planet
      (magnitude 1.4) will be about 3 times fainter than Saturn (magnitude

      Although the planets and our Moon will appear to be close together,
      there's no danger of a collision. While the Moon is only 384,000 km
      away from us this week, Mars is 349 million km away; Jupiter is 875
      million km away; and Saturn is a whopping 1493 million km distant.
      When it comes to the sky, appearances can be deceiving!
      Jupiter, Mars, and Saturn will appear to be even closer together on
      April 15 when the three will fit inside a circle less than 5 degrees
      across. That's the most compact grouping of any 3 planets for the
      entire year. Nevertheless, the display on April 6 will be more
      beautiful thanks to the delicate crescent Moon as it passes by the

      But wait, there's even more: Cradled in the arms of the crescent Moon
      will appear the ghostly outline of the full Moon, a dim glow that
      astronomers call "Earthshine." Like all the planets we see in the
      night sky, the Moon shines because of reflected sunlight. The side of
      the Moon facing the sun shines brightly, and the side facing away is
      nearly dark. The only significant illumination on the "dark side of
      the Moon" is due to Earthshine -- sunlight that bounces off the Earth
      and falls on the lunar surface. A slender crescent Moon with
      Earthshine is widely regarded as one of the most delicate and
      beautiful sights in the night sky. It will be difficult to see from
      urban areas, but should be easy to view from dark sky locations.

      When Planets Align (or "Taking Nostradamus to School")

      [line_neg.gif] The April 6 grouping of Mars, Jupiter and Saturn is
      just the prelude to a grander alignment on May 5, 2000. On that date,
      the Moon, Mercury, Venus, Mars, Jupiter and Saturn will all converge
      in an area of the sky less than 25 degrees across. Unfortunately, the
      spectacle will be lost in the glare of the Sun, which will be right in
      the middle of this planetary get-together!
      Although the May 5 alignment won't produce a visible sky show, some
      people are touting the event. Why? According to doomsayers, the
      alignment will cause earthquakes, floods, and maybe even split our
      planet in two like a meat cleaver through a head of lettuce! In all
      fairness that sounds like an event to note on your calendar.

      If these sensational claims sound familiar, it probably means you were
      alive 38 years ago when there was a similar celestial alignment. On
      February 4, 1962, the Sun, the Moon, and all the planets from Mercury
      to Saturn were clustered within a 17-degree area of the sky. To top it
      off there was a total eclipse of the Sun! Doom seemed certain to many
      astrologers and students of Nostradamus.

      In the May 1962 issue of the Griffith Observer, astronomer Robert
      Richardson described the scene in Los Angeles on February 4, 1962:

      Weeks beforehand we began getting inquiries [at the Griffith
      Observatory] from people wanting to know, "What was going to
      happen? What does it mean?" ... Sunday, February 4 [the crowd at
      the Observatory] must have been the largest since it was opened to
      the public in 1935. By two o'clock the road leading to and from the
      observatory was a solid mass of cars lined up bumper-to-bumper for
      half a mile. One woman was weeping so badly it was hard to
      understand her. She was practically on the verge of collapse. "I
      know it's silly to carry on this way,' she gasped between sobs,
      'but I can't help myself." [[4]ref]

      Fortunately, nothing happened. There were no severe earthquakes, no
      devastating floods, no mass destruction. With no planet-wide disaster
      to spoil the day, millions of onlookers enjoyed [5]the solar eclipse.

      History shows that planetary alignments are harmless. In fact,
      alignments like the one in 1962 and in 2000 are fairly common. The
      five naked-eye planets cluster together in the sky within a circle 25
      degrees or less in diameter once every 57 years, on average. The next
      time it will happen is September 8, 2040. The 2040 grouping will
      include Mercury, Venus, Mars, Jupiter, Saturn and the crescent Moon.
      Clustered well to the east of the Sun, the planets will stage a
      spectacular show at 7:30 p.m. in the evening. (Mark your calendar

      If planetary alignments are common and the Earth is never destroyed,
      why do predictions of doom seem to attend each one?
      Many people believe that when planets are aligned their gravity and
      tidal forces are magnified, leading to extraordinary effects here on
      Earth. This seems reasonable. After all, "spring tides" (peak ocean
      tides that arise bi-monthly) occur when the Sun, the Moon and the
      Earth are nearly in a straight line around the times of the New Moon
      and Full Moon. Shouldn't even more powerful tides arise when lots of
      planets are lined up?

      Maximum Tidal Forces of the Sun, Moon, and Planets on the Earth

      Moon 2.1
      Sun 1.00
      Venus 0.000113
      Jupiter 0.0000131
      Mars 0.0000023
      Mercury 0.0000007
      Saturn 0.0000005
      Uranus 0.000000001
      Neptune 0.000000002
      Pluto 0.0000000000001

      We can calculate the maximum tidal force that each planet has on the
      Earth. These values are shown in the table. Tidal effects depend on
      distance and mass--but especially distance. Tides decrease in
      intensity as the cube of the distance to the source of gravity. (If
      you move twice as far away from a planet, its tidal force decreases by
      23=8 times). That's why the strongest Earthly tides are caused by the
      nearest object -- the Moon. If all the planets were to align perfectly
      with each one as close as possible to the Earth, their gravity would
      raise the ocean tides by just one twenty-fifth of one millimeter.
      Typical ocean tides on Earth caused by the Moon and Sun are thousands
      of times larger than that. Clearly, the contribution of the planets is
      entirely negligible, and it makes no difference to the Earth whether
      they are aligned or not.
      Above: In this table, adapted from the Griffith Observatory's
      "[6]Planetary Alignments in 2000", the Sun exerts 1 unit of tidal
      force on the Earth; the Moon has a little more than twice the effect
      of the Sun; the other nine planets together with all their moons add
      only another one five-thousandth as much.

      So, if you've already packed away your Y2K survival gear, don't worry.
      There's no planet-rending catastrophe in the offing. Like most other
      5ths of May, the one in the year 2000 is a more appropriate occasion
      for Cinco de Mayo festivities than for disaster planning.
      For lesson plans and educational activities related to planetary
      alignments, tune into the March 30 episode of [7]Thursday's Classroom.
      There is also [8]a version of this story for kids at NASA/Marshall's
      [9]NASA Kids web site.

      Web Links

      [10]Planetary Alignments in 2000 - from the Griffith Observatory

      [11]Do planetary alignments cause earthquakes? - find out at


      2. mailto:duane@...
      3. http://www.spacescience.com/news/subscribe.htm
      4. http://www.griffithobs.org/SkyAlignments.html
      5. http://sunearth.gsfc.nasa.gov/eclipse/SEcat/SE1901-2000.html
      6. http://www.griffithobs.org/SkyAlignments.html
      7. http://www.thursdaysclassroom.com/
      8. http://kids.msfc.nasa.gov/news/2000/news-planetalign.asp?se
      9. http://kids.msfc.nasa.gov/
      10. http://www.griffithobs.org/SkyAlignments.html
      11. http://www.badastronomy.com/bad/misc/planets.html

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