[mandevil]

A great example of this is the Sagnac Effect. In 1913, French Physicist Georges Sagnac built a circular interferomter and found interference bands. He thought that this disproved Relativity and showed that an aether existed, but it turned out that German Physicist Max von Laue had predicted the existence of those interference bands under relativity two years earlier, so 10 points for Einstein. (Note that the named credit for the effect went to the experimental physicist who found it, even with a wrong theory, rather than the theoretical physicist who worked earlier and correctly predicted it.)

For the next 50 years Sagnac interferometery was a dead end, a minor curiosity in the history of physics. Then in 1963, Macek and Davis at the Sperry Gyroscope Co. figured out how to build this in a laboratory environment with the recently invented lasers. The coherent beam of a laser unlocked the usefulness of the Sagnac effect. Meaning that just another 30-odd years of work by hundreds of people around the world got to a situation where fiber-optic gyros are superior to mechanical gyroscopes and capable of things that mechanical gyros could never do. But all sorts of things with scary names like "anti-Shupe winding" had to be invented and then perfected to get these fiber-optic gyros to be so good, and that was the result of many people, who probably all knew each other through the conference circuit and in meetings, sharing ideas and then improving on each other's ideas. So who gets the credit for the Fiber-Optic gyros? Sagnac? Laue? Macek and Davis? Shupe? What about Ring-Laser, which is different in engineering but also based on Sagnac interferometry?

So, the Sagnac effect itself was worth nothing, and for a long time afterwards was just something that a few scientists even knew about. But a century later- and with the hard work of hundreds to thousands more people- the world depends on it.

In an alternate dimension, I got a Ph.D in this sort of stuff- I am truly fascinated by it. But I decided to try and be one of the engineers today rather than documenting what the engineers of the past did.