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Einstein Revisited

Entry 309, on 2006-04-05 at 18:38:51 (Rating 1, Science)

Over a year ago, on the occasion of the centenary of Einstein's Theory of Relativity, I blogged about what an amazing contribution he made to science, and remarked about the incredible accuracy and foresight of his theories. Some of his contributions were developments of existing work in physics, but others just seemed to come from nowhere.

One reason he was so successful was that he ignored conventional wisdom and instead based his theories on what fitted the maths and what seemed most "right" from his own perspective. My current reading on the history of science shows he made a few errors though, and ironically these were on the occasions that he refused to ignore traditional ideas, and changed his theories to fit them.

The most obvious example of this was regarding the expansion of the Universe. His equations in their original, simple, elegant form showed the Universe would be contracting due to gravity, so he invented an extra term which he called the "cosmological constant" which repelled mass and prevented the contraction. Its value could be set to whatever was required to negate the contraction and this would give the static Universe that conventional wisdom demanded.

He later called this his biggest mistake. After the expansion of the Universe was discovered through galactic redshifts, he had to admit that the constant wasn't required because the Universe was expanding from an initial state and this expansion would totally or partly overcome gravitational attraction.

The incredible irony of the whole thing is that now, with the latest observations, there seems to be a repulsive force at work after all, due to the presence of a mysterious phenomenon known as dark energy. The Universe's expansion should be slowing due to the pull of gravity, but it is actually accelerating, which means a repulsive force must be acting on it. The inflationary phase of the Big Bang also requires this phenomenon.

So maybe the cosmological constant was a good idea in the end, after all, and yet again, Einstein got it right. My personal thoughts are that when a theory of quantum gravity is finally produced we will find that dark energy and inflation are natural consequences of the new theory. I don't have a lot of real scientific evidence to support this idea, but some recent observations point in this direction, and it just seems to be "right". Maybe Einstein would approve, although quantum gravity will be the theory that will replace his own General Relativity which in turn replaced Newton's Theory of Gravity.

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