Truly Trivial: What famous physics phenomenon did Einstein refuse to believe was possible?

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Ninety-four years ago this week, Albert Einstein published his general theory of relativity -- for which he would not win the Nobel Prize in Physics. This is not to say Einstein never won a Nobel -- he did, in 1921 -- but it wasn't his work in relativity that earned him the most respected accolade in science. Einstein won his Nobel for his work on the photoelectric effect, rather than relativity. Basically, what made Einstein famous isn't what earned him praise from his scientific peers -- at least not initially.

Indeed, Einstein's work on relativity put him at odds with some of the most imminent minds in the history of physics, including Neils Bohr (with whom Einstein waged a series of friendly if highly contest debates on quantum mechanics) and Karl Heisenberg. Often, Einstein proved his critics wrong, rewriting central theses of physics as he went. Still, Einstein was not infallible, and he not infrequently was proven wrong.

Ironically, one of Einstein's most famous missteps was a lifelong refusal to accept the possibility of a certain famous astrophysical phenomenon. Even more ironic, this theoretical basis of this phenomenon is based almost entirely on Einstein's own principles of relativity.

What famous astrophysical phenomenon -- proven possible by relativity -- did Einstein spent his career arguing against?