More to Explore 115
It was while riding on a Berne, Switzerland, trolley car in the spring of 1904 that the
image first flashed across Albert Einstein’s mind. It was an image of a man in an elevator
that was falling from a great height. Einstein realized immediately that the image of this
“thought experiment” could bring focus to a problem that had been plaguing him (and all of
science) for years.
Einstein realized that the man in the elevator would not know he was falling because,
relative to his surroundings (the elevator), he wasn’t falling. The man—like us—would not
be able to detect that he (and his elevator) were caught in, and being pulled by, a gravitational field. If a horizontal light beam entered the side of the elevator, it would strike the far
wall higher up because the elevator would have dropped while the light beam crossed. To
the man, it would appear that the light beam bent upwards. From our perspective (relative to
us), gravitational fields bend light. Light not only could be, but routinely was, bent by the
gravitational fields of stars and planets.
It was a revolutionary concept, worthy of one of the world’s greatest scientific minds.
Einstein regularly used these imaginative “thought experiments” to shed light on complex
questions of general principles. It was a new and unique way to approach the study of physics and led Einstein to write a series of four papers, which he submitted to a science journal
in 1905. One of those four papers presented the special theory of relativity (relativity princi ?W2?VBF?&?F?W2V?F?W"??f??rB7FVG?fV??6?G??"B&W7B????&W76VB?F?R??W&???V&?6?VB??f?W"W'2??6??v?R?77VR???F?W"&W6V?FVBV??7FV??( ?2&V?F???&WGvVV???GFW"?BV?W&w???F?RW'2g&??F??2( ??FWW.( ??F?V?F?6???BFVW???7F?B??B&?f?V?BVffV7B??F?R66?V?F?f?26???V??G????Rv266WFVB2F?7F?&?F?W6?2'??W&?6?V??fW'6?G??v??6?w&?FVBV??7FV????B??f?'GV??????6?6?7G26??gFVBF?V?"7GVF?W2F?f?7W2??V??7FV??( ?2F?V?&?W2???b?v?F?v"&v??r7&?72WW&?R?V??7FV??V&?6?VB??2vV?W&?F?V?'??b&V?F?f?G??v??6?FW67&?&VB&V?F?f?G?F?V?'??VBF??&?V7G2??f??r????&R6???W?v?0?v?F??????V"66V?W&F????F?Rv?&?B?VFVB??gV?f7G3?vR???rF?BF?R?????B6?V?B?b??f??r?&?V7G2V ??B6?V?BF?ffW&V?BFWV?F??r??v?WF?W"F?R&V6V?fW"?27FF???'?? ???f??r?7V6??&V?F?f?G??2&6VB??F?R??B?&?vv??r6??6WBF?B?????GFW"??rf7B??RG&fV??F?R7VVB?b?v?BV'2F?&V???F?R6?R????&RF?W???&P?&'GW6????&6??V??7FV??( ?2V?f???6?VB7??????7FV???rF?F?R6?V?G2?`?76R?F??R?v6???wF???D3???6W??V?'?&W72?#??&W&?7FV????W&V??V??7FV????Wr??&?åV?wV?????R??'&???FV??2?V??7FV????fR??Wr??&??????v??W?b6??2???b??6?&?6R??6R?F?RV?F&?RV??7FV???&??6WF????&??6WF??V??fW'6?G?&W72????b??f??6??r??'&V6?B??&W'BV??7FV???&??w&????Wr??&??f????r???r??v??G6?F??F???B?F?RV?F??FRV??7FV????Wr??&??'?&??&W72???r??