Some family history goes into this one as my mother loves Einstein. She said, “Don’t be dogging my man, and please don’t tell me it was his hair… I love that hair…”

Well, not to worry mom and other fans, I love his hair too, but most modern physicists agree on this one. Einstein’s biggest mistake was tossing the cosmological constant into the trash. Murphy is laughing from the grave as even the most brilliant man history is not impervious to his law. So what happened?

When developing General Relativity, Einstein added a constant term to compensate for the “static” universe. It was not known at the time that galaxies were zipping away at faster and faster rates. It is hard to imagine a time when the Big Bang was not a part of cosmology but those were the days that Einstein developed his theories in. That makes his discoveries even more astonishing.

According to Einstein, since the universe was “static” it needed some way to not collapse in on itself due to gravity. That was the first time ever that a cosmological constant was used in physics, simply to correct Einstein’s equations and produce a universe that would remain “static”.

Fast forward a decade or two and the outlandish evidence provided by Hubble has made it to main stream science. It was clearly evident that the universe was expanding and that a Big Bang, or some point in time when all the stuff in the universe was much closer together, explained this well. Now, the universe had an extra momentum, and so came Einstein’s biggest mistake.

To paraphrase mom’s “man”, Einstein called the cosmological constant of General Relativity his “biggest mistake,” and removed it from his equations. He thought that if the universe was not “static” then there was no need for an extra constant to keep the universe from collapsing. So, following Murphy’s Law, Einstein does the worst thing he could with the cosmological constant by simply eliminating it.

Fast forward to the 1990’s and astrometry changed the world of physics again with the discovery of dark energy.  To compensate for dark energy, the cosmological constant was reintroduced into General Relativity. Nearly four decades after Einstein threw it away, and all other theoretical physicists, the science community came to the conclusion that what Einstein’s called his “biggest mistake” was actually the dominating force of the universe. Oops!

Image via Wikipedia This picture is for you mom.

Special thanks to moms who hate to be called mother, you know who you are.

By: Richard Nelson