Einstein's “biggest blunder” - or was it?
Albert Einstein
As kids we were taught "to err is human." But can a towering scientific figure like Einstein err? To lesser mortals like us, it is comforting to know that the answer to the questions is "yes." We seldom realize that when we try to study the Universe, it has many ways of humbling us, irrespective of whether we are adept or inept, astute or obtuse. At every opportunity it reminds us that our mundane theories and fertile imaginations are woefully inadequate to unlock the enduring mysteries of the gargantuan Universe. In 1915, after the completion of his General Theory of Relativity, Einstein was chagrined to find a near-fatal flaw in the theory. No matter how he solved the equations, they stubbornly indicated a Universe that is dynamic. The thought of an expanding Universe with a beginning, the Big Bang, struck at the very core of his belief in an "unchanging," steady-state model of the cosmos. It was like an unhittable curve-ball thrown at him. In a misguided attempt to make the Universe static, Einstein did what most of us do when theoretical predictions go awry and disagree with experimental result. He introduced a "fudge factor" in the equations and fine-tuned its value to make the Universe static, neither expanding nor contracting. He coined the term "cosmological constant" for the factor and interpreted it as a repulsive force required to stabilize the Universe and make it motionless. Einstein probably was unaware of physicists' mantra: "No theory should agree with all the data, because some of the data are sure to be wrong." In 1929, the great astronomer Edwin Hubble's discovery of an expanding Universe gave Einstein the goose bumps. Much to his consternation, Hubble's observation supporting the Big Bang Model made Einstein go back to the chalkboard and rethink about the cosmological constant. In 1931, he realized his mistake and embraced the Big Bang Theory as "the most beautiful and satisfactory explanation of creation which I have ever listened." He referred to the fudge factor as "the biggest blunder of my career." Had he not been so inflexible in his belief in a steady-state Universe, Einstein could have added another feather to his multi-feathered cap - correct explanation of why the Universe is not static. The controversy over the cosmological constant, however, did not end with Hubble's discovery and Einstein's admission. Forty three years after Einstein's death, studies of exploding stars in distant galaxies revealed that the Universe is not only expanding, it is doing so at an ever-faster rate. Astronomers started pondering: What could be the cause of this accelerated expansion? Could the expansion be propelled by a repulsive force much stronger than the attractive gravity, but acting in the opposite direction? Whatever it is, the mysterious cosmic force causing the Universe to accelerate is neither matter nor radiation. Hard to believe though, it was Einstein's infamous fudge factor that came to the rescue. His cosmological constant was resuscitated and shown to be the manifestation of a yet to be detected phantom energy - Dark Energy, which is responsible for causing the expansion of the Universe to accelerate. Thanks to the exploding stars, Einstein's reputation albeit slightly dented by his misplaced faith has been restored and he has been rehabilitated to his original stature again. "So was it really a blunder to propose a concept so useful to cosmology?" asked cosmologist George Gamow, a proponent of the Big Bang Theory. Blunder it was; but one thing is certain, the blunder turned out to be one of Einstein's greatest contributions to cosmology, an interesting embellishment of the Big Bang model. A constant that was introduced to make the Universe immobile has been revived to make it mobile. Its influence increases as the Universe expands. As Einstein said: "Anyone who has never made a mistake never tried anything new."
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