[DIGEST: CNN, Space.com, Universe Today, NASA]

It has been one hundred years since Albert Einstein came up with his crowning intellectual achievement–the theory of relativity. That theory, published in 1915, posited that space and time are part of a single, interwoven continuum called spacetime. More importantly, spacetime itself is malleable and “warps” under the influence of matter. What we know as gravity is actually the bending of spacetime by objects with mass.

Einstein’s theory has survived over a hundred years, having been put to rigorous testing and come out unscathed. But recent conclusions on the accelerating expansion of the universe corroborate a further idea Einstein had posited–and rejected–nearly a century ago.

#### Defying Gravity

Einstein, like most in his time, held to a “static” view of the universe, believing that without a “cosmological constant” in his equations (a repulsive force that countered the effect of gravity), the matter in the universe ultimately would draw itself into a single point. So Einstein added that cosmological constant to his initial equations in 1917 as a kind of “fudge factor,” seeking to zero out the effect of gravity so that the universe stayed in a constant state.

Then, in 1929, the cosmologist Edwin Hubble proved through his observations of infrared light that the galaxies were actually moving away from us. The universe was not static at all, it was expanding. This startling observation suggested that at one point the entire universe arose from a single point, giving rise to what is now the “Big Bang.” The proof of the expanding universe caused Einstein to regret having added his cosmological constant, so he removed it from his equation, reportedly calling it his “biggest blunder.”

But was it? Scientists now believe that Einstein’s dismissal of the cosmological constant may actually have been premature, and that he would have been right, in a sense, to have included it all along.

**The Ever-Expanding Universe**

Prior to 1998, common scientific thought was that gravity would eventually pull space inward, creating what they called a very hot “Big Crunch.” Essentially, if the universe began with the Big Bang, which inflated the universe with a huge expanding force, then the

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