1.  The abbreviation used for the speed of light.
3.  A very hot gas ball composed mostly of the element hydrogen.
5.  An oscillatory motion of something in nature.
7.  A spacecraft built by the European Space Community and launched 
     in December 1995.
8.  Sometimes called the fourth state of matter.
11. The third planet from our Sun.
12.  ____ cloud - A spherical region in which a trillion or so comets are 
      stored.
13. An atom (or molecule) that has lost or gained one or more electrons and 
      therefore is electrically charged.
14. Sometimes called the Northern Lights.

2. The large collection of stars in fairly tight gravitational connection with each 
    other.
4. The smallest particle into which an element can be broken.
6. A Japanese spacecraft, with significant U.S. and U.K. contributions, launched 
    in 1991 that performs dynamic x-ray imaging of the Sun.
8. Usually the most distant planet from the Sun (although Neptune is sometimes 
    further out).
9. An electrical conductor used to send or receive radio signals.
10. The path or trajectory of a body in space.