1.   The height above a planet's surface.
3.   Solar _ _ _ _ _ - A very rapid release of energy from the Sun's surface.
5.   A unit of electromotive force that will cause a current of one ampere to flow 
      through a resistance of one ohm.
6.  A bundle of light energy thought of as a particle but not having real mass.
7.  A spacecraft launched on September 25, 1997 to measure the composition of 
     the solar wind.
8.  An atom (or molecule) that has lost or gained one or more electrons and therefore 
     is electrically charged.
9.  The symbol used for the speed of light.
10. The abbreviation for electromagnetic radiation with wavelengths that are just 
      a little shorter than visual light.
11. The negatively charged particle in the portion of an atom outside the nucleus, 
      the very dense central part.

1.  Something that occurs in an electrically charged gas in which the vibration 
     of the magnetic field part of it is perpendicular to the direction of travel of it.
     (2 words)
2.  An electrical conductor used to send or receive radio signals.
4.  The smallest particle into which an element can be broken.
6. Mercury and Earth are examples of  one of these.