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,
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
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.
(Photo by author)
The Engines of Our Ingenuity is
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