Complex sentence: The season opened to a Nielsen rating of 8.8 percent according to Nielsen Media Research for the second part of "Scorpion" when it aired on September 3,1997, meaning that it was watched by 8.8 percent of those watching television at the time of broadcast.
Split into simpler sentences: The season opened to a Nielsen rating of 8.8 percent for the second part of "Scorpion" when it aired on September 3,1997. A Nielsen rating of 8.8 percent means the episode was watched by 8.8 percent of those watching television at the time of broadcast.