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Voices of the Clarion: Everything's relative

Einstein's theories changed the way we see our world

Posted: Sunday, May 15, 2005

First, synchronize your watches and then head off on a walk to the store with your daughter, but tell her to run and you'll catch up later.

Now unless you've somehow adopted an adult older than yourself, she's clearly younger than you. But if she beats you to the store even by a little bit, the physics of our universe will have produced an effect you might find surprising.

She'll be even younger, compared to you, than she was when you both started out, albeit by an infinitesimal fraction of a second. The fact is, she'll have aged a tiny bit slower than you, and by virtue of being in motion, you'll both have aged slower than mom who stayed at home.

Now unless you're wearing a pretty exotic wristwatch, one that marks time in fractions of nanoseconds, you're not going to notice. The time change will have been far, far too small. But it will be there nevertheless.

One hundred years ago this June, the notion that motion makes one mature slower than a person at rest was just one of the weird and wonderful consequences to emerge from a radical new way of looking at the physical world published in a paper by a little-known German patent clerk, a "technical expert, third class," named Albert Einstein.

Fact is, Einstein's paper, "On the Electrodynamics of Moving Bodies," published June 30, 1905, required acceptance of some other not-very-obvious realities — such as the faster you go the more foreshortened (in the direction of travel) you become as measured by someone standing still.

Simply put, moving clocks (all kinds of time-measuring devices, including the grandfather clock in the corner, biological organisms like the cells in your body, the decay rates of subatomic particles) run slower than stationary clocks, and the faster they move the slower they go compared either to slower-moving clocks or stationary clocks. In addition, rulers like Miss Crabtree's classroom yardstick or the length of your nose, shorten the faster they move compared to their motionless counterparts.

OK, admittedly this all seems rather odd, but that's because it isn't something we see in everyday life. At very slow speeds, even when our fastest rockets are involved, these effects of time dilation and space foreshortening simply are too small to notice. But start moving at half the speed of light or more, say, and the effects will become stunningly apparent.

Without delving too deeply into the physics, the "gedanken," or "thought experiments" that led Einstein to write his 1905 paper were an attempt to explain some disturbingly annoying results coming out of ever more sophisticated efforts during the late 19th century to measure the speed of light, and also to test a presumption that light waves needed some kind of medium through which to propagate (similar to air for sound waves).

Scientists once assumed the existence of something they called "the ether" — an apparently mass-less presence that pervaded all nature that gave electromagnetic waves like light a medium through which to move.

It turned out no medium was necessary, AND no matter whether you were standing still or rocketing along at a significant percentage of the speed of light (roughly 186,000 miles per second), you would measure light waves (or photons) traveling by you at exactly that speed and no other. In other words, whether you were heading straight toward a source of light, or exactly away from it, the light speed you measured from that source would be 186,000 miles per second.

It is not the same thing as standing on the nose of a rapidly moving train and firing a bullet from a high-powered rifle. In that case, the two speeds would add together, and the bullet would be traveling, at least initially, at its muzzle velocity plus the speed of the train. Exactly the opposite effect would occur if you stood at the back of the caboose and shot to the rear.

Again, this is not what happens to light leaving a flashlight from the engine of caboose of a train. No matter how fast the train, the photons of light leaving it travel at precisely the speed of light no matter who measures them.

The concepts outlined in the 1905 paper launched the 20th century into an era of unprecedented advance. But "On the Electrodynamics of Moving Bodies," which later became know as his Special Theory of Relativity (distinguishing it from the General Theory of Relativity published in 1915), was just one of five brilliant papers produced during a period that has come to be called Einstein's Annus Mirabilis, or year of miracles.

In the course of some six months, Einstein also published a paper proving that light not only exhibits the property of waves, but sometimes the properties of particles, or quanta; two papers on Brownian motion — the hitherto unexplained dance exhibited by pollen particles suspended in fluid as seen in a microscope first noted by Scottish botanist Robert Brown in 1827 — that essentially proved the existence of molecules and atoms and predicted their typical sizes; and a paper demonstrating the equivalence of matter and energy — two manifestations of the same phenomenon — that included his now famous equation E=MC2.

It was Einstein's ability to define a question and then doggedly pursue an answer that may have been his true genius. For instance, it is said he spent a decade pondering the effects one might see traveling near the speed of light, before publishing "On the Electrodynamics of Moving Bodies." Often it was not a matter of covering pages with esoteric calculations, but rather his willingness to abandon the conventions of the day, that led him to make such breakthroughs.

He would go on 10 years later to publish the even more world-altering General Theory of Relativity, a true work of genius — perhaps the greatest in history — that among other things showed gravity was not some kind of mysterious attraction between masses, but a property of matter that warped space and time like a cannon ball on a trampoline.

Born in Ulm, Germany, in 1879, Einstein was, if anything else, an intensely curious being, right up to the day he died of heart failure in Princeton, N.J., in 1955. He once wrote that he was not so much interested in one phenomenon or another, but in how God created the world.

"I want to know His thoughts; the rest are details," he said.

He also had a free spirit's sense of humor and irony, as exhibited by the following quotes.

"The hardest thing in the world to understand is the Income Tax," he said.

Or, "We can't solve problems by using the same kind of thinking we used when we created them."

And finally, he had a gift for the controversial, yet profound, utterance, such as:

"Science without religion is lame. Religion without science is blind."

In December 1999, Time Magazine named him "Person of the Century."

He was that — at the very least.

Hal Spence is a reporter for the Peninsula Clarion.


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