Engines of Our Ingenuity

No. 2145:
EXTREME TIME

by John H. Lienhard

Today, extreme time. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Years ago, an army colonel asked me, "So, Corporal, how much longer will you be in the army?" Perhaps he understood how seriously I chafed to get out when I answered, "Oh, about 2-1/2 mega-seconds, Sir." (That was a month before I could muster out.)

My subjective view of time was not the same as his. Now I read physicist Robert Jaffe's article on time, and he goes a huge step further. He writes, "In the twentieth century we lost our bearings in time as utterly as our forebears in the Renaissance lost their special place in the universe."

To explain that, Jaffe offers a diagram showing durations of many events -- an eye-blink, the age of the Earth, the switching time of a transistor. The diagram passes through 86 orders of magnitude. That is, 86 factors of ten.

The shortest event is the so-called Planck time -- ten-to-the-minus-43 seconds. It turns out that the subtlety of quantum mechanics denies us any idea of time shorter than that.

The longest known time is the half-life of a proton -- around ten-to-the-plus-43 seconds. That's vastly longer than the age of the universe. You and I experience time near the middle of this scale. We can perceive times as small as a hundredth of a second. And, at just under 31.5 million seconds per year, our lives last around 2.3 billion seconds. Our hands-on experience with time runs through only eleven factors of ten, while modern science has to cope with 86 factors of ten.

No wonder science and religion live in such uneasy peace. The pre-scientific religious scriptures tell of our relationship with God. But they also warn that God's magnitude is beyond anything our own minds can contain, and that's where we stumble. The Church once balked when science showed that planets weren't perfect crystalline spheres -- then again, when the universe ceased to be centered on Earth.

In the nineteenth century we learned that much in the universe has to be explained with time-spans far greater than nine thousand years. Now, Jaffe says, twentieth century science again stressed our psyches by describing events vastly longer or shorter than any hope of human conception -- times that can only have abstract meaning to us -- numbers of seconds with oh-so-many zeros in them.

The problem gets worse in many ways. Events of very short duration and very small size -- far below human comprehension -- are dominated by completely different forces. At the same time, the weakest of those forces, gravity, dominates behavior of only large systems -- people, stars, galaxies.

Even within human perception meaning changes with scale; I've lived my 2.3 billion seconds, and yet I look back over life and see only thousand-second bursts -- a concert, a hurtful argument, the arrival of a good idea or a good friend, an accident, a fine meal. All those are very real. But 2.3 billion seconds? Well, a lifetime remains as far beyond me as the age of the universe.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


R. L. Jaffe, As Time Goes By. Natural History, (Magazine of the Houston Museum of Natural Science) October 2006, Vol. 115, No. 8, pp. 16-22.

Complex Clock
(Photo by author)


The Engines of Our Ingenuity is Copyright © 1988-2006 by John H. Lienhard.