[DoughnutHole]

Einstein’s work on the photoelectric effect was incredibly important, and incredibly influential on other research at the time. He proposed that light was quantised - essentially the foundation of quantum mechanics.

It’s no exaggeration that Einstein’s work on the photoelectric effect was as important as special or general relativity, and it had the advantage of strong experimental verification by 1921.

The main reason that prize is remarkable is that Einstein himself hated quantum mechanics - but that doesn’t dispute the work’s importance.

[trashtester]

The discovery of the photoelectric effect was certainly as important as relativity in terms of how much it affects society. But it was only an incremental advanced on top of Planck work on blackbody radiation.

I'm not saying that photoelectric effect didn't deserve a Nobel Prize. But relativity completely supplanted Newtonian Physics, and Einstein played a much greater role in this revolution than he did in that of Quantum Mechanics.

Also, I believe historical records have made it clear that relativity, even if it was still considered controversial in the '20s (and so not mentioned specifically), was indeed part of the reason he was awarded the prize.

Also, consider WHY it was still controversial, despite evidence piling up even for relativity. It was seen as such a fundamental shift away from common-sense understanding of the physical world that people refused to believe it, despite evidence.

Just like how many people to this day do not believe it's possilbe to build AI out of regular computers, as their intuition tells them that some magic vodoo needs to be there for "true" inteligence.

[topaz0]

I would add to this that it had the advantage of something like 40 years of history as a field that was the basis for some of the biggest advances in instrumentation of that era.