NEW YORK – The Sept. 11, 2001, terrorist attack is by far the most memorable moment shared by TV viewers during the past 50 years, a study released Wednesday concluded.

The only thing that came close was President John F. Kennedy’s assassination and its aftermath in 1963, but that was only for the people aged 55 and over who experienced those events as they happened instead of replayed as a historical artifact.

Sony Electronics and the Nielsen TV research company collaborated on the survey. They ranked TV moments for their impact not just by asking people if they remembered watching them, but if they recalled where they watched it, who they were with and whether they talked to other people about what they had seen.