MIT’s Edgerton Center holds free Science on Saturday programs five times a year for elementary, middle, and high school students — as well as their parents and teachers.  On October 17, the program will be focused on Planets:  Pluto and Beyond.  Kids under 12 must be accompanied by an adult.  The program includes a one-hour presentation at 10AM followed by hands-on activities at 11AM.  No pre-registration is necessary but seating is limited and first-come, first-seated.  It’s held in MIT’s Kresge Auditorium, 48 Massachusetts Ave. in Cambridge.