Today, the last Christmas Eve of the Second Millennium. 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.

In a lifetime of Christmases, I've never seen one quite like the Christmas of 1999. It doesn't take a rocket scientist to figure out that the tension and buildup this time around is in our heads. But that doesn't make the tension go away. The tension is not about Y2K bugs, terrorism, or the end of the world. It is, instead, about a kind of responsibility. For Christmas and the New Year impose a pair of nearly subliminal demands upon us.

For the Eastern Church, Christmas is the first major feast of the year. For the Western Church, it's a season that begins on December 25th and straddles the New Year. Either way, Christmas and the New Year bring with them their linked demands for reconciliation and renewal. And this is only the second time these demands have marked, not just a new year, but a new millenium as well.

It was one thing to blow it in 1846 or 1983. Somehow it seems to be a thousand times worse to blow it in 2000. So tonight we begin a singular Christmas season -- a seeming chance to get it all right, not for one year, but for a thousand. (It'd be a scary thing if that kind of responsibility were really thrust upon us.)

Well, we're not apt to transform the world in the next few days. The New Year will arrive, just as all the others have. But this time, we'll walk away from it knowing that we're in a new time zone, whether we want to be or not. Try this exercise: I'll say two phrases for you and ask what you see when I do:

First, I'll say: Nineteenth Century. Second, I'll say: Twentieth Century. When I do that, I first see horses and buggies, bicycles with big front wheels, hoop skirts, and cowboys and Indians. Second, I see airplanes, hospital operating rooms, chemistry laboratories, and automobiles. Each century has a radically different personality. That's why, this Christmas, you can become a totally different creature in the eyes of your yet-unborn great-grandchild.

When that child thinks about you, will she think about your birth date or your death date? Will she see you as a creature of the second millenium or the third? When I think of Max Planck, I think of the 20th century, even though he was born in 1858. That's because Plank was a formative agent of the century in which he died. On Christmas Eve, 1899, Planck was about to initiate the quantum revolution -- the great revolution of the twentieth century.

Frederic Remington was born three years after Planck. But he represents the nineteenth century. Remington's art defined the Wild West we all know.

So this Christmas Eve will separate two human epochs. We'll wake up in January, not much changed. Yet history will make a watershed of it nevertheless. The very tension we invest in this season will demand that it be a watershed. This is the New Year none of us will forget. This is the one in which the world will change simply because we won't have it otherwise.

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

(Theme music)

Nativity Scene by Petrus Christus