Observations that broke the rules?

[Brad12d3]

It seems like there has been a couple of times in the history of physics when we have observed something that seemed to break the rules of accepted theory. What do think were some of the most surprising discoveries in the last 50 years or so that broke the rules of what what we thought was possible?

[sophiecentaur]

The first counts of neutrinos detected going through the Earth were much lower than expected. Later on they found there was more than one type of neutrino and the original prediction was justified. The measurement method was missing a lot of them!

[Dotini]

It seems like there has been a couple of times in the history of physics when we have observed something that seemed to break the rules of accepted theory. What do think were some of the most surprising discoveries in the last 50 years or so that broke the rules of what what we thought was possible?

To dim little old me, the observation that galactic rotation defies Newton's laws of gravity is the most surprising and important. It is this observation that necessitates ideas of dark matter, and drives us to the uncomfortable position that up to 96% of the universe is invisible, undetectable, and may forever remain so. It's almost like being forced into believing in magic.

Respectfully submitted,
Steve