To the editors:
I read with interest your column [The Straight Dope] which appeared in the Reader of June 17th attempting to answer a question about what would happen if one were to attempt to travel at or near the speed of light. You correctly explained that at that speed one's headlights would work normally and that they would also appear to work normally to a stationary observer. Unfortunately after that you lapsed into a bunch of nonsense about being "squished," measurements being "thrown off," and "nobody knows how fast you're 'really' going." Please get it straight.
Einstein's Special Theory of Relativity shows that time, length and mass are entirely dependent on the frame of reference in which they occur. Someone in the car in the problem in your column is "really" traveling at 0.99c, within their frame of reference. The stationary observer sees the car "really" traveling at a different speed. Each is correct within their own frame of reference. There is no ultimate reference frame, as your response leads the reader to believe, that is any more real than any other. Length, time and mass "really" are whatever they are within each frame of reference, although they change when measured from one reference frame to another. While it is true, as you so quaintly put it that "everything's relative," each observer can also determine the speed of any object within any other frame of reference, provided that they know the relative speeds of the different reference frames.
I realize, of course, that the majority of your readers who live along North Lake Shore Drive have not previously been exposed to relativistic physics. It is included, however, as a regular part of the physics course which is required of virtually all the students who attend the public high school where I teach in Englewood, just west of the Dan Ryan Expressway on the South side. If your readers want to give me a call I'll arrange for them to visit Paul Robeson High School and my students will explain it to them. Failing that, they can read Relativity: The Special and General Theory by Albert Einstein (no math beyond algebra and geometry is required) or Was Einstein Right? (he was, as far as he went) by Clifford M. Will.
Austin A. Winther
Science Department Chairman
Paul Robeson High School
Cecil Adams replies:
You may understand relativity, Austin, but irony is obviously beyond you. The quote marks around "really" and the reference to God being the only one who "really" knows how fast you're going were an attempt to convey (futilely, in your case) that there is no ultimate reference frame and thus no way of determining absolute speed. After you get done with the physics buffs down at Robeson, come on up to the office and we'll work on Humor 101.