100 Hours of Astronomy Begins . ... Credit Copyright: Tamas Ladanyi ( TWAN ) Explanation: Today, 100 Hours of Astronomy begins, a cornerstone project of the International Year of Astronomy 2009 celebrating the 400th anniversary of Gallileo's original telescopic exploration of the sky. Running from April 2 through April 5, many different public programs are planned worldwide as part of the project, starting with today's opening event at the Franklin Institute in Philadelphia. ...