When coal came into the picture, it took about 50 or 60 years to displace timber. Then, crude oil was found, and it took 60, 70 years, and then natural gas. So it takes 100 years or more for some new breakthrough in energy to become the dominant source. Most people have difficulty coming to grips with the sheer enormity of energy consumption.
When I was a child I asked my mother what homosexuality was about and she said - and this was 100 years ago in Germany and she was very open-minded - 'It's like hair color. It's nothing. Some people are blond and some people have dark hair. It's not a subject.' This was a very healthy attitude.
Einstein had two new predictions from general relativity. One was that light would bend. That was tested in 1919, and basically, he was proven right. The second prediction was gravitational waves, which took us 100 years to prove. The theory itself, which is thought by most to be rather obscure, you use every day, probably.
People are going to be living quite soon for 100 years. Our idea of how a family works no longer applies. It's no good saying you're going to have children for 15 years and then you're going to retire and have hobbies, because you've got 40 more years to go after 60 and you're in good health until 90 or something.