Galileo's Pendulum

Like Tupac Shakur, Albert Einstein looms large in the popular imagination after his death. Seemingly every story relating to quantum entanglement must mention Einstein’s famous phrase “spooky action-at-a-distance” (spukhafte Fernwirkung), every article on dark energy references “Einstein’s greatest blunder”. New ideas about gravity or experiments that seemingly violate the speed of light summon Einstein’s shade. (I’d refer to Einstein’s unquiet grave, but he was cremated and his ashes scattered. Well, except for his brain and eyes, which were stolen out of his corpse before cremation.)

In a Slate “Future Tense” article this week, I took issue with New York Times science writer Dennis Overbye’s framing of a debate over black hole firewalls. The firewall discussion is interesting and very challenging; I don’t claim to understand all the details, though I haven’t spent much time on it either. (Beyond the Einstein thing, I found Overbye’s article a bit muddled; you might do better with either Jennifer Oullette’s or Zeeya Merali’s takes.) My point was that invoking Einstein is a distraction, which ends up making real physics research into a battle of personalities:

The Albert Einstein of the popular imagination can seem a bit like Scott Pilgrim, forced into battle with new theories and young physicists. Whether he’s pitted against experiments finding faster-than-light neutrinos (a result that turned out to be spurious) or fighting possible alternatives to his theory of gravity, you’d be forgiven for thinking that physics is Albert Einstein vs. the World. [Read more…]

(Alas that nobody has taken up my challenge to draw Einstein as Scott Pilgrim in full kung-fu pose. Bryan Lee O’Malley has so far declined to comment.)

I won’t rehash my piece, but there’s another reason why invoking Einstein can backfire: sometimes the quote is out of context … or possibly apocryphal. That truly seems to be the case for “Einstein’s greatest blunder”, as Rebecca Rosen pointed out in The Atlantic. The facts of the case: Einstein added a term into his gravitational field equations to make them compatible with an eternal, static Universe. That term, called the cosmological constant, is mathematically allowed, but it had to have a very precise value to keep the Universe from expanding or contracting. Einstein removed the term again when Edwin Hubble announced the discovery of cosmic expansion.

According to the story, passed around so much that it must be true, Einstein called the cosmological constant his “greatest blunder”. However, as Rosen describes, physicist Mario Livio (who was my graduate advisor for two weeks) investigated the provenance of that phrase for his most recent book and determined that there’s no reason to think Einstein ever said it. The “greatest blunder” story comes from George Gamow, himself a famous cosmologist, who told the story after Einstein’s death. Livio postulated that Gamow may have made it up to exaggerate his claims to friendship with the older physicist, but whatever the reason, there’s no other source for the phrase.

I for one am happy if the “greatest blunder” turns out to be completely apocryphal, if it stops people from putting the phrase into every blasted story involving dark energy. Yes, cosmic acceleration may correspond mathematically to a cosmological constant, but its purpose is opposite to that of Einstein’s. When the old boy introduced the cosmological constant, it was possible and maybe even reasonable to think the cosmos was eternal and static. However, the cosmological term today possibly arises from the quantum vacuum that drives expansion to faster rates, conceptually a very different beast than Einstein’s corrective mechanism. While Einstein’s term reined in cosmic expansion, dark energy eggs it on.

Einstein was eminently quotable, which is both a blessing and a curse. (If I never see “Imagination is more important than knowledge” quoted again, I wouldn’t shed a tear.) Lovely quotes have a way of being taken out of context, and quotable people often end up with others’ words misattributed to them. Maybe the death of the “greatest blunder” myth will help us be a little more cautious when we invoke Einstein.