Seems to be the first time this was confirmed via direct experimental observation of the orbitals:

  “This idea that relativity is important in heavy elements has been around since the 1970s,” said Lai-Sheng Wang, a professor of chemistry at Brown and the study’s corresponding author. “But we show direct spectroscopic evidence that what we learned in high school about chemical bonding isn’t true in heavy elements."

In general, yes. Spin-orbit coupling and relativistic effects in heavier elements is not new. A rather... significant elements where this was studied was uranium (and plutonium, of course). Even napkin maths show that for heavy elements, some of the electrons have relativistic velocities.

This discovery is about a (seemingly, I haven't been keeping up too much) new case of one specific bond in one specific ion. Do not read the university's breathless press release, go straight to the article. The third sentence of the editor's summary is "It’s long been clear that this model starts to fray when the atoms get heavy enough for relativity to come into play".

Yes, I was taught that relativity is a significant part of quantum chemistry equations in gold atoms 25 years ago. The idea is quite old and the title is misleading.

The article seems to be more specific, about relativistic effects in triple bonds

The Dirac equation which is the equation for describing the wavelike behavior of electrons. It predicted the existence of antimatter and particle spin.

You start with the Schrödinger equation, add relativity to get the Klein-Gordon equation which is a mess because it's second order in time involving negative probabilities, if you in ways "take the square root" of it you get the Dirac equation.

Relativity has been part of the understanding of electrons since 1928.

https://en.wikipedia.org/wiki/Dirac_equation

There's even a Wikipedia page for it https://en.wikipedia.org/wiki/Relativistic_quantum_chemistry

Yes: the article says "since the 70s"

Gold electrons at inner orbits travel at a large fraction of the speed of light, which is why gold isn't a silver color. That is really neat.

I don’t get it, someone explain? Doesn’t everything get color from relativistic effects?