Einstein's relativity rules chemical bonds in heavy elements, new research shows

357 points - yesterday at 10:30 PM

https://www.science.org/doi/10.1126/science.aei1285

Comments

gcanyon today at 12:40 PM

> The increased nuclear mass causes orbiting electrons to speed up to a significant fraction of the speed of light, where the rules of Einstein’s theory of relativity are important.

Fun fact: this is why mercury is liquid at room temperature. Its inner electrons move at close to 60% the speed of light, pulling in its outer electrons more tightly, making it harder for it to bond and be solid. (I am not a physicist, don't rely on my statements for your space ship design)

kristianp yesterday at 10:39 PM

> The increased nuclear mass causes orbiting electrons to speed up to a significant fraction of the speed of light, where the rules of Einstein’s theory of relativity are important.

> In the relativistic regime, an electron’s spin — the magnetic moment that points either up or down — and the electron’s orbit are no longer independent of each other, a state known as spin-orbit coupling.

Interesting stuff. I've never heard of sigma or pi bonds.

https://www.science.org/doi/10.1126/science.aei1285

nanolith yesterday at 11:31 PM

Wait... wasn't it already understood that relativity influences electron orbits of heavy elements? I clearly remember being taught some of this in physics, in the mid-noughties.

For instance, we know that gold gets its color from relativistic effects.

https://physics.aps.org/articles/v10/s3

de6u99er today at 11:13 AM

It's beautiful to see Einstein's work still being validated.

RetroTechie today at 12:29 PM

"Bismuth could be an alternative to toxic lead in next-generation solar cells."

Is lead still used in common, mass-produced solar panels currently on the market? Wikipedia:

"Lead-based semiconductors such as lead telluride and lead selenide are used in photovoltaic cells and infrared detectors."

Wiki page for lead telluride mentions thermo-electric materials, page for lead selenide mentions IR imaging & detectors. Neither page even mentions solar panels.

Searching turns up mentions of use in flexible solar panels, which have a tiny market share. And iirc some/most of those use cadmium rather than lead compounds? (ok cadmium is equally nasty)

There's mention of lead solders used in solar panel construction. Leaded solders have been banned in EU due to its RoHS directive for a looong time, spare a few niche applications. Solar panels among those? If ever: still the case in 2026?

True: bismuth is used in some solders for similar reasons as lead.

And ofcourse there's recycling. One source mentioned ~0.1% of recycled panels by weight. Another source says overall lead content lower-level than safety limits for material on children's playgrounds.

All in all, that "toxic lead" statement reads more like outdated info. If not FUD.

Svoka yesterday at 10:49 PM

For context: this is one more experimental confirmation of Dirac's equations (incorporating special relativity into quantum physics).

Very cool.

The paper PDF: https://bpb-us-w2.wpmucdn.com/sites.brown.edu/dist/0/196/fil...

cyberax yesterday at 11:05 PM

Relativity is also responsible for a lot of weird behaviors of heavy elements, such as the color of gold. Or that lead is a good material for batteries.

westurner today at 1:29 PM

But what about superfluids (BEC Bose-Einstein Condensates)?

Is it a different set of rules for superfluids like 3He, or should the laws of superfluids cover heavy elements, too?

Here, again, a need for a model of superfluid quantum gravity

michaelsbradley today at 3:36 AM

Can equivalent theoretical predictions be calculated in a Bohmian framework for the quantum aspects, or is this (potentially) an interesting case where there’s divergence and falsifiability?

waldrews today at 3:08 AM

Very farsighted, after working as a patent clerk, to lay claim on such a foundational technology. Back in the day, they must've been like, oh, so Mercury blocks the sun at the wrong time, but where's the commercial value - and now every chemical company throughout the universe is about to get a bill every time they make something more complex than hydrogen gas.

Meanwhile, Galilean relativity has long gone out of patent, and people on board planes and other vehicles just move around like they were in a stationary reference frame paying no royalties.

14 today at 2:45 AM

I had a couple drinks so having one of those moments. I am always so fascinated by the science and experiments done to prove what we know. I consider myself at least of average intelligence probably slightly above but the things scientists research and solve always blows me away.

My guess to the Fermi paradox is that there actually are intelligent life across the universe but just like in Star Trek they stay quiet until we reach a certain level of knowledge.

devmaster2 today at 12:00 PM

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zkmon today at 3:27 AM

In general, anything that is observed to be true at a smaller scale or context can't be extended to much larger scales. That involves assumptions on logic and mathematics to be homogenous across all scales. A pure theoretical extrapolation without bounds is quite common in mathematics, such as proof by induction etc.

Also, the foundational axioms of logic themselves could be valid only at a scale that is familiar to humans. For example, the strict bounday between true and false might get blurred and things could be true and false at the same time at other scale.