You would think by now we would have exhausted the mysteries of Albert Einstein. As perhaps the most famous scientist in history, nearly every idea he expressed and every thing he did has been studied, commented on, written about. Yet on his 135th birthday (born March 14, 1879) there are still new details coming out–details that offer insight both into the workings of Einstein’s mind, and into the biggest mysteries of the cosmos. One big Einstein shocker was unearthed recently by Irish cosmologist Cormac O’Rafferty while digging through the Einstein Archives at Hebrew University in Jerusalem. There he found a completely overlooked manuscript– undated, but probably from 1931–that showed Einstein trying to create a model of the universe that satisfied both his scientific insights and his philosophical inclinations. The manuscript, entitled “About the Cosmological Problem,” envisioned a universe that expands but that (through a clever trick of physics) never really changes. In 1917, Einstein made his first attempt at constructing a physical model of the universe. Actually, I should say that he made the first ever attempt at building a physical model of the universe; nobody before had the mathematical or conceptual tools to venture there. Einstein had just published his General Theory of Relativity, and wanted to see what would happen if he applied his new ideas about space and time to the cosmos as a whole. He soon realized that his equations naturally predicted either an expanding or contracting universe, contrary to both to the astronomical understanding of the time and to his preferred view of the order of nature. So Einstein added an extra factor, which he called Lambda, that would counteract gravity and allow the whole system to stay beautifully in balance. Then in 1929, Edwin Hubble uncovered evidence that the universe is, in fact, expanding, and Einstein quickly abandoned Lambda. This part of the story is well known. It just turns out to be wrong. The Unknown Einstein O’Rafferty discovered that, 14 years after his first cosmological paper, Einstein was still experimenting with Lambda and still trying to figure out how the universe could remain in some kind of perfect balance. Amir Aczel gives some excellent background to the story in his recent blog post. Why Einstein thought that the universe should be in balance is significant. In keeping with his overall principle of relativity–that nature looks the same to all observers–Einstein believed in the “cosmological principle”: that the universe is homogeneous, overall, so that it appears the same from any location in space. But he was also drawn to a deeper version, the “perfect cosmological principle,” which holds that the universe should also look the same from any location in time. Obviously that cannot happen in an expanding universe…or can it? How Einstein tried to solve the problem is also really interesting. He imagined that, as space expands, new matter appears out of nowhere to fill the new empty space. The two processes balance out, so that the average density of the cosmos never changes. The well known Steady State model of cosmology, proposed in 1949, is very similar to Einstein’s abandoned (and never-published) theory. Not until the 1960s, when the evidence for the Big Bang and the finite age of the universe became truly persuasive, was the Steady State model discredited. Say, did you notice that I mentioned Einstein’s idea of matter appearing out of nowhere? That seems to contradict conservation of mass, doesn’t it? Yes, but remember that our modern understanding of dark energy is equally paradoxical. As space expands, it creates more energy, which causes the expansion of the universe to accelerate. Energy from nothing. Since mass and energy are equivalent, the current accepted reality is no stranger than Einstein’s model. The answer may lie in a deeper understanding of the energy fields that permeate seemingly empty space (or, from a different perspective, in the relationship between
Posted on: Sun, 16 Mar 2014 18:44:17 +0000