April 2008 - The Spring Sky

the changes we experience on earth coincide with changes we observe in the night sky. Just as most people each year anticipate spring’s arrival, so also we anticipate the new constellations and celestial wonders that arrive with the season.  In addition to the seasonal changes in the night sky, each month offers us the familiar cycle of the moon waxing from new moon to full and waning back to the old moon before repeating the cycle.   Although this cycle is repeated every 29 days, most of us are thrilled with the view of a new moon and never tire of seeing earth’s landscapes illuminated by a bright full moon.

The beginning of a new season invites us to reflect again on our place in the cosmos.   Timothy Ferris writes, “We’re all star people, in the sense that we’re all created from star stuff, so it’s in our genes, so to speak, that we’re curious about the stars.   They represent an ultimate power, something we cannot physically grasp.   When people ask, ‘Why, God?’ they don’t look down at the ground.  They look up at the sky.”   P. 48, Seeing in the Dark.
   

Those who have watched bright Venus in the morning sky might wonder what has happened to the “morning star.”   Venus may be barely visible just before sunrise early in April.  In its shorter orbit around the sun, Venus is racing to “opposition” – a position on the other side of the sun from the earth.   For the next few months we will have difficulty seeing Venus as it is in an almost direct line of sight with the sun.  In June, Venus will emerge into our evening sky and become a prominent “evening star” throughout the fall.  Although Saturn’s rings are closed more tightly than at this time last year, this planet is the highlight of our spring skies.  Mars continues into the spring directly overhead but moves slowly to the east each night.   By the end of April watch for Mars to be directly lined up with the two bright stars, Castor and Pollux, known as the Gemini twins.  Jupiter rises in the east after midnight and will put on a great summer show again this year. 

Mark April 8 on your calendar for viewing the moon alongside the Pleiades star cluster.  Binoculars will reveal dozens of bright stars in this beautiful cluster just below a crescent moon.  If you watch the moon over the course of the evening you will notice its motion against the background stars.  Then on April 11 look for a close encounter of the moon and Mars.   As you look to the heavens that evening you may want to ponder the vast distances of our celestial neighbors.   Light from the moon takes less than 2 seconds to travel to us while light from Mars can take up to five minutes to reach us.   But light from the Pleiades Star cluster takes almost 400 years to reach us.   And if you have a clear, dark sky you might even glimpse the faint patch of light of the Andromeda galaxy.   The light you see from Andromeda began its journey to us over 2 million years ago.   Whether light has had a short journey to us from within the solar system or a longer journey from within our galaxy or an extremely long journey from another galaxy, we should out to welcome it when it arrives.
    What is the bright star, slightly reddish, appearing each night in the northeast?  This is the star, Arcturus.  If you follow the handle of the Big Dipper in an arc, you will come to Arcturus.   Continue a straight line through Arcturus and you will come to the bright star, Spica.   An easy way to remember these stars is with the saying, “Draw an arc to Arcturus and drive a spike to Spica.”  

As we anticipate April showers we hope these will allow many clear nights to enjoy the wonders of the night sky.