QUESTION:
Are there any new theories on how the water vapor got into Juipter's
atmosphere?

ANSWER from Elias Barbinis on January 30, 1996:
The presence of water on Jupiter is due to two sources:
   1. The primordial solar nebula from which Jupiter and the
      other members of the solar system were formed.
   2. The comets which have collided with Jupiter since its
      formation.