A study released today reveals the most memorable TV moments of the past 50 years, the Associated Press reports, with one event coming in far ahead of all others: the Sept. 11, 2001, terrorist attack.

“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 an historical artifact,” the story reports.

The survey, which ranks events by their impact on viewers, is a collaboration of Sony Electronics and the Nielsen television research company. It takes into account whether people remember watching particular events on television, whether they remember where they were at the time, who was with them and whether they discussed what they had watched.

“By that measure, the Sept. 11 tragedy was nearly twice as impactful as the second-ranked moment, which was the coverage of Hurricane Katrina in 2005,” the story reports. “Minutes after the first airplane struck New York’s World Trade Center on a late summer morning, television networks began covering the events continuously and stayed with them for days.

“The other biggest TV events, in order, were the 1995 verdict in O.J. Simpson’s murder trial, the Challenger space shuttle explosion in 1986 and the death of Osama bin Laden last year, the survey found.”

Brian Siegel, vice president of television business for Sony, said he expected entertainment events to rank higher, but instead the study found that TV coverage of news events had the greatest impact on viewers.

The study found "that television is really the grandmother of all the social devices," Siegel said.

Examples of major entertainment events, and where they came in on the survey, include the final episode of "M*A*S*H" (ranked No. 42), the Beatles’ appearance on "The Ed Sullivan Show" (No. 43) and the "Who shot J.R.?" episode of "Dallas" (No. 44).

The report notes: “The Super Bowl is annually the most-watched TV event, with this year’s game between the N.Y. Giants and New England Patriots setting an all-time record with 111 million viewers. The memories don’t seem to linger, however: The top-ranked Super Bowl Sunday event in Sony’s study came in 2004 and had nothing to do with football. It was Janet Jackson’s wardrobe malfunction (No. 26).”

Differences were noted between men’s and women’s responses. “For example, women ranked the 1997 funeral of Princess Diana as the fourth most memorable event, while men put that at No. 23. Women ranked last year’s death of Whitney Houston at No. 5, with men judging it No. 21,” the story reports. “Similarly, the 2003 bombing of Baghdad at the start of the Iraq War was seen as the No. 14 most impactful moment by men, and No. 37 among women. Men were also far more struck by boxer Mike Tyson biting off a piece of Evander Holyfield’s ear.”

Older events had trouble competing with more recent events, simply because younger viewers don’t remember them. For example, the first manned moon landing, in 1969, came in at No. 21.

Not surprisingly, big differences were noted by age: “JFK’s assassination was the second-most impactful TV event among people 55 and over, while for those between 18 and 34, it was the death of Osama bin Laden,” the story reports. “Young people also ranked Barack Obama’s Election Night speech in 2008 at No. 3, while that didn’t move older viewers quite as much (No. 24).”

Historic events including the JFK assassination, President Nixon’s resignation and the moon landing “didn’t register at all among viewers 18 to 34,” the report notes. “The oldest event to appear in their rankings was the 1980 shooting of John Lennon.”