"As constant as the heavens." That's a standard way of praising changelessness in God's firmament, and to our perceptions at least, changeless the heavens are. Most of the stars we see in the night sky have been shining for billions of years, their courses so predictable that they move precisely as the ancient astronomers predicted long before Christ was born.

Permanence in the physical universe - as opposed to the living biosphere, which knows endless turmoil - is sometimes used as an argument for the existence of God. Only a higher power, it is supposed, could have created a universe of such subtle design that it can exist in a stable condition for unfathomable lengths of time. Current estimates place the universe at between 12 billion and 15 billion years of age, and projected to continue in approximately its present form for hundreds or thousands of billions or years to come. And only a higher power could have created physical laws and constants so reliable that mathematicians find them beautiful, such as the value pi. The early 20th-century physicist Erwin Schrödinger, who helped postulate the "wave" model of the atom, numbers among the many modern scientific thinkers who have mused that it is hard to fathom that the beauty and permanence of physical law developed on a chance basis alone.

But suppose the heavens are not absolutely constant, and physical laws change over time. Would this be an argument against a creator God, or at least for a revolution in cosmology?

Slightly changing physical law is what a group of astronomers led by John Webb, of the University of New South Wales, in Australia, think they may have found. Writing in a recent issue of the technical journal Physical Review Letters, Webb described his team's search for evidence of "alpha" in the early universe. Alpha is, like pi, a "transcendental number"--a natural constant that holds under all circumstances. Pi, known to high-school students, represents the ratio of the circumference of a circle to its diameter, and is always and everywhere 3.14159.

Alpha is more complicated, a numerical relationship among the charge of electrons, the speed of light and a physics value called Planck's Constant. Wherever in the universe alpha has been observed, it is always 1/137th--often spoken by physicists, for the sake of simplicity, as 137. Point your telescope where you please and, in the enormity of the 40 billion known galaxies, you will observe alpha at 137.

We'll skip here the fact that 137 is also the number of the kabala, the system of mystic Jewish numerology. Though some have attempted to attach spiritual significance to this, it's probably just a coincidence. There are, after all, lots of important numbers in physics--3.14159, to cite one--that don't correspond to anything spiritual.

What Webb and his fellow astronomers did was point their telescopes not at a place but at a time: at the oldest known quasars, extraordinary and mysterious objects the size of our sun but as bright as entire galaxies. The oldest quasars came into existence in the dawn epoch, perhaps 12 billion years ago, and their extreme power is presumed to have something to do with the genesis of the universe itself. And when the astronomers checked the oldest known quasars for alpha, they did not get the number 137, but a value slightly lower. Alpha, their findings suggest, has been growing over time.

Perhaps one set of physical laws was necessary to cause the Big Bang and other physical laws will be employed in the future. What might these future sets of physical laws make possible?

If this finding withstands further scrutiny (currently, it has physics abuzz), it may overturn one of the most cherished premises of modern science, "uniformitarianism." That is not an obscure Protestant denomination but the contention that physical laws do not change: that the universe we observe today is the result of the forces we observe today, and therefore we can reason backward to prior conditions.

Uniformitarianism was proposed by the great 19th century geologist Charles Lyell to explain the finding that had the science world of the 1830s abuzz, namely the layered rocks and fossils that suggested the Earth was extraordinarily old. (About 4.5 billion years old, according to current theories of dating.) If Earth has existed for billions of years, thinkers of the time ruminated, how will we ever have even the slightest clue what the ancient past might have been like? Lyell answered, by assuming that physical forces have always been the same, and then reasoning backward from what we observe today to what must have existed before.