Albert Einstein didn’t like it. When he worked out his General Theory of Relativity in 1916 he realized that it made for an unstable universe. The General Theory is all about gravity and it has been one of the most successful theories of all time. It has stood up to every observation and experiment that scientists have thrown at it. But Einstein didn’t like the implication that the universe should collapse under its own gravity. He grew up in a world that took it for granted that the universe was infinite and eternal. That it was complete, done, cooked to perfection. When his theory threatened to upset that, he decided that there must be another force working to balance gravity. He stuck it in and called it the Cosmological Constant. Later he was to call it his “biggest blunder.” When astronomer Edwin Hubble announced in 1929 that galaxies in all directions appear to be moving apart, Einstein realized that the universe is expanding. That was why it wasn’t collapsed long ago by gravity. He abandoned the Cosmological Constant, disgusted with himself.In his lifetime he saw the birth and growth of what would become the Big Bang theory. If everything was moving apart then it was logical that it was closer together in the past. Go back far enough and it was all in one place. A little less than 14 billion years ago the universe as we know it burst into existence, according to the Big Bang Theory, and it has been expanding ever since. In the 1960s, a very sensitive microwave receiver used in Bell’s communication network was plagued by persistent background noise. After weeks of trying to track it down, including the eviction of a couple of resident pigeons, the technicians, Penzias and Wilson, realized it was real microwaves coming from space. It was the cool afterglow of the Big Bang explosion.
In the decades since, observations have been refining the data and developing the theory. The Hubble Space Telescope, other observatories and legions of cosmologists have looked deep into the expanding universe and have given us the clearest picture ever. One surprising datum they’ve come up with is that, rather than the expansion slowing down under universal gravitation, it is actually speeding up. Some force seems to exist in the fabric of space which is accelerating its expansion. Some people are calling it the Cosmological Constant.
It wasn’t quite as big a blunder as Einstein thought.