Einstein, ca. 1930. On the blackboard is Rik = 0, a tensor form of his ten field equations for pure gravitation
Update [30 DEC 1999]
Albert Einstein became Time magazine's Person of the Century, nosing out distinguished also-rans like Franklin D. Roosevelt and Mahatma Ghandi. Time described the theoretical physicist as "unfathomably profound -- the genius among geniuses who discovered, merely by thinking about it, that the universe was not as it seemed." The magazine gushed that the "bumbling professor" was "the embodiment of pure intellect. Even now scientists marvel at the daring of general relativity."
Worth waiting: Another proof of Einstein
Stand on the pitcher's mound and pitch a fastball. Now make the same throw from the front seat of a roller coaster.
Common sense and experiment both say that someone standing on the ground will see the faster throw coming from the roller coaster. Now repeat the experiment pointing a flashlight straight ahead and measuring the speed of its light. Oddly enough, it won't matter whether you're sitting on a roller coaster, a space ship, or your front porch. The speed of light is constant, immutable. And it doesn't matter where you observe it from either. Light speed is light speed. End of story.
Very counterintuitive, as physicists like to say when explaining stuff that obliterates common sense.
And important. After all, it was a similar test of the speed of light, the famous Michelson-Morley experiment of 1887, that set the stage for the scientific revolution called relativity. (Did we catch you reaching for the mouse? About to change the channel? Admit it. You were going to tune out just cuz we mentioned Albert Einstein's theory of relativity, the crowning achievement of physics. Mistake. Stick around. There's plenty here to entertain the curious.)
Einstein came up with the theory during the first 15 years of the century, based in part on the observation that light violated the accepted "Newtonian" physics of the day.
A kiss is just a kiss.
But is a theory just a theory?
A theory starts as a mere explanation for how nature works. To be accepted as a valid theory, it must be tested to see if it actually explains how nature works.
The easiest way to test is to try to disprove whatever the theory predicts. Does your theory say that gravity is an attraction between any two objects? Then try to find two objects that don't attract each other. If you do, it's back to revise or abandon your theory.
Relativity was a profound theory, and it offered oodles of predictions -- but most were difficult to test. Did objects gain mass as they accelerated close to the speed of light? Perhaps, but at a time when automobiles could barely outrun waddling penguins, nobody could figure how to test that prediction.
Did massive rotating objects distort space and time around them, as two physicists predicted in 1918 based on relativity? Perhaps, but the effect would only be noticeable near something considerably larger than a roulette wheel, and scientists couldn't get their hands on anything that massive.
Fortunately, some of the predictions were easier to measure. In 1919, scientists gathered the first proof that Einstein had it right -- when they measured a bending of light rays passing near the sun. So gravity could affect light -- as Einstein claimed.
Suddenly, instead of being viewed as an eccentric oddball, Einstein became a celebrity. A reluctant, slightly disheveled one, but a celebrity nonetheless.
And that was only the first of many proofs of Einstein's predictions.
