The Sept. 11, 2001, terrorist attack on the World Trade Center is television's most powerful moment of the last 50 years, according to a study released on Wednesday. While few will be surprised that 9/11 topped the list, there were some surprising results among the rest of the rankings.

The study, conducted by Sony Electronics and Nielsen television research, measured the most impactful moments in TV history based on participants' recollections of televised events. The results were compiled through an online survey of 1,077 adults selected at random by Nielsen, the company that measures TV ratings.

Because the survey was based on personal recollections, events from further back in history placed lower on the list simply because fewer people alive today remember them. Hence Neil Armstrong's historical 1969 moonwalk ranked 21 while 1999's Columbine school shooting ranked 11.

Freshly etched moments seemed to gain a decided edge, regardless of historical significance - which should explain why recent events like the death of Whitney Houston and the wedding of Prince William and Kate Middleton ranked higher than the 1963 assassination of John F. Kennedy. In fact, nearly half of the events in the top 20 took place within the last decade, despite the fact that the study looked at events from the past 50 years.

Age was a strong dividing line for determining the participants' personal rankings. JFK's assassination fared significantly more impactful for people over 55, who ranked the event at number 2. Conversely, people 18 to 34 saw far more historical import in Barack Obama's 2008 election-night speech, ranking it at number 3. Gender was not as strong of a dividing line. Men and women largely agreed on the top three events, with some interests diverging lower down the list.  

But it was the events of Sept. 11, 2001, that reigned most historical and everyone's mind. The attacks were by far the most memorable moment for TV viewers regardless of age or gender, ranking nearly twice as impactful as the Hurricane Katrina disaster, the second-highest event on the list.

Sony participated in the Nielsen study with the hope of gleaning clues into consumers' behaviors and interests. Television is really the grandmother of all the social devices, Brian Siegel, Sony's vice president of television business, told AP.

However, Siegel said that he was surprised that the most impactful events were historical, while entertainment-related events placed lower on the list. The final episode of M*A*S*H, for instance, ranked 42, and the Beatles' appearance on The Ed Sullivan Show ranked 43. 

Below are the top 20 most powerful moments, according to the study.

1. September 11 terrorist attacks (2001).

2. Hurricane Katrina (2005).

3. The O.J. Simpson verdict (1995).

4. The Challenger space shuttle explodes (1986).

5. Death of Osama bin Laden (2011).

6. The O.J. Simpson White Bronco chase (1994).

7. The Japanese earthquake and tsunami (2011).

8. Columbine school shooting (1999).

9. BP oil spill in Gulf of Mexico (2010).

10. Princess Diana's funeral (1997).

11. Death of Whitney Houston (2012).

12. Capture and execution of Saddam Hussein (2006).

13. Barack Obama Election Night speech (2008)

14. Wedding of Prince William and Kate Middleton (2011).

15. John F. Kennedy assassination (1963).

16. Oklahoma City bombing (1995).

17. Bush/Gore disputed election (2000).

18. Los Angeles riots, Rodney King beating (1992).

19. Casey Anthony murder trial verdict (2011).

20. John F. Kennedy funeral (1963).