Mini-Throughput: Einstein’s Greatest Mistake Edition

I was somewhat bemused to see this video from Dennis Prager claiming that, apart from the physics, Einstein was kind of mid as an intellect. His evidence for this is that Einstein was a pacifist and pacifism is stupid, especially for a Jew in the context of World War II.

Of course, being Prager, he gets some basic facts wrong. While Einstein was a pacifist, that was mostly in the context of World War I, one of the most unnecessary calamities in human history. During World War II, he not only recognized that war was necessary, but contributed to the development of the atomic bomb that brought about its end. He was specifically quoted as saying he was not an “absolute pacifist” and that Hitler was a menace to civilization.

Of course, Prager’s real target here is not Einstein but a more broad attack on experts of any variety. This has become a big thing on the Far Right lately. And while I think skepticism of experts is reasonable, dismissal is not. If I’m sick, I want to go to an expert — a doctor. If I want a room added on to my house I go to an expert — an architect. If I’m in trouble with the law, I will go to an expert — a lawyer. I might differ with them on specific details. But only a fool would build a house, treat a disease or go into court without at least getting the opinion of an expert. Expertise is good, actually.

But I want to talk about Einstein specifically. Einstein was a brilliant physicist but he also had lots of insights into human nature. There are entire pages of quotes from him on every subject from life to politics to war to philosophy. And while I don’t agree that they are all gems, they demonstrate a relentless and curious mind that was fascinated by every aspect of human existence. They are the musings of a true deep thinker.

But this is kind of beside the point. Saying that, apart from the physics, Einstein wasn’t smart is like saying, apart from her face, Helen of Troy wasn’t very interesting. Or that aside from his painting and sculpting, Michelangelo wasn’t very skilled. Or aside from the plays, Shakespeare was kind of meh. Einstein was a once-in-millennium intellect who transformed how we see the world.

gravitational lens G2237 + 0305 — sometimes referred to as the Einstein Cross. The photograph shows four images of a very distant quasar which has been multiple-imaged by a relatively nearby galaxy acting as a gravitational lens. The angular separation between the upper and lower images is 1.6 arcseconds. Photo by NASA, ESA, and STScI, Public domain, via Wikimedia Commons

And he keeps transforming it. Just this year, we confirmed the existence of massive gravitational waves generated by the collisions of supermassive black holes. Which means, Einstein, who has been dead for 68 years, has been right more often in the last two months than Prager has been in his entire life.

“Einstein has made a universe and I can’t tell you how long that will last.”

Literature laureate Bernard Shaw, born #OTD 1856, pays tribute to physics laureate @AlbertEinstein at the Savoy Hotel in London, England, 27 October 1930. pic.twitter.com/2YyaROKaq1

— The Nobel Prize (@NobelPrize) July 26, 2023

Einstein saw the world as no one had ever seen it. He had the kind of insight that maybe a handful of human beings have had in the entirety of human history, glimpsing the engines of the universe the way Neo could see the Matrix. His theories transformed not only our understanding of physics, but of cosmology, chemistry, astronomy and warfare. And just to show you how much of a genius Albert was, let’s talk about what he himself called his biggest mistake.

When Einstein published his theory of General Relativity, he was confronted with a problem. The theory predicted that the universe might not be stable. At the time, it was thought that the universe was eternal and unchanging, like a giant clock that could spin forever. But relativity indicated that the universe might actually contract under its own gravity. To fix this problem, he tried to develop the idea of a cosmological constant, a force that would stabilize the universe by counter-acting gravity. The problem he encountered and never solved was that this actually made the instability problem worse. Unless gravity and the cosmological constant were exactly balanced, the universe would either expand exponentially or contract exponentially.

The Hooker telescope, with which Hubble glimpsed the expansion of the universe.

As he was working on this, Edwin Hubble discovered that the universe was, in fact, expanding. This transformed our entire view of existence — that the universe as not eternal and unending but had a beginning and possibly an ending. When he heard about Hubble’s discovery, Einstein abandoned his work on the cosmological constant, later calling it his “greatest mistake”.

This story is a perfect illustration of why experts are so important. Because even when they’re wrong, they’re wrong in useful ways. They’re wrong in ways that point you to the truth. They’re wrong in ways that leave a trail so you can figure out where the misstep was made. Einstein was, or so he thought, wrong about the cosmological constant. But his realization that relativity was not consistent with a static universe pointed the way to Hubble’s discovery and the correct interpretation of it. A true genius lights the path even they’re wrong.

And sometimes … they’re not even wrong.

And there begins the second half of our story. For seven decades, Einstein’s Greatest Mistake sat in physics textbooks mostly as something to throw at students when we talked about theoretical universes. It was an interesting concept to play around with, to see what would happen if there were a cosmological constant. But it did not seem to apply to anything real.

However, in the late 1990’s, our telescope technology had improved to the point where it was possible to measure the deceleration of the universe. As the universe expands, the gravitational pull of its contents slows the expansion down. If there is enough matter, it could even reverse the expansion. When we measured the Hubble constant — the rate at which the universe is expanding — we were measuring its expansion now. However, when we look at distant galaxies, we are seeing the universe as it was millions or billions of years ago. In principle, we could measure the universal expansion slowing down. Distant galaxies would show a universe expanding faster than today’s universe. And we would be able to measure how fast that expansion was slowing and therefore how much matter the universe had.

The result, however, was shocking. We found that the universe wasn’t decelerating at all. In fact, it was accelerating, expanding faster and faster over time. This force causing the acceleration is called dark energy.

We have no idea what dark energy is or how it works. In fact, our best theories are off by 120 orders of magnitude, or roughly half of what RFK, Jr. is typically wrong by. But, given what we know at present, dark energy could be consistent with Einstein’s cosmological constant. And even if the cosmological constant isn’t quite what we’re seeing, it’s a useful frame to study the issue and explore dark energy’s effects upon the past, present and future of the universe.

In other words … Einstein’s greatest mistake may not have been his greatest mistake. It may have been his most spectacular and enduring insight. It was just sitting there, on a shelf, neglected, for seven decades. But it now represents the biggest mystery in astrophysics and our biggest gap in understanding the universe.

I don’t write this post to defend Einstein. He is generally regarded as one of the most brilliant people of all time, to the point where his name is synonymous with genius. But I write this to tell you that no matter how smart you think he was, he was smarter even that that.