"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.

It turned out there was a substantial body of evidence for Lyell's assumption - we can skip the details here, except to say that the first big public debates concerned how river valleys were formed. (Was it the biblical flood or gradual erosion? This topic was as hot in the 1820s as the topic of God-versus-Darwin is today.) Uniformitarianism took over the study of geology, and then biology, and then cosmology. Throughout the 20th century, essentially all important theorists have worked from the assumption that the constants of physics, and the behavior of the heavens, have been uniform throughout all history.

When the Big Bang was concept was first proposed, by the Belgian priest Georges Lemaître, one of the objections to the idea was that it violated uniformitarianism, since compressing all the substance of the entire universe into a single point (a "primordial atom," as Lemaître said) could not happen under known physical law. As evidence of the Big Bang has accumulated - mainly, that the galaxies are racing outward from what appears to have been an ancient central location, as if once flung apart - theorists have adjusted the theory to say that the primordial condition, in the instant before the Bang, was governed by unknown physical laws. But the Big Bang brought current physics into being, and nothing as changed since.

Now the Australia astronomers suggest that laws of physics can change. If they're right, what might this mean?

Short answer: we have absolutely no idea.

Supposing that a creator God is behind the universe, who can say what the celestial master plan calls for? Perhaps one set of physical laws was necessary to cause the Big Bang, another to nurture the early universe, another is in force now - seeming unalterable on the time-scale that we can observe - while still other physical laws will be employed in the future. What might other, future sets of physical laws make possible? That's unknowable, but it is worth pointing out that many of the world's religions (including the monotheist faiths Judaism, Christianity and Islam) describe current temporal existence as a transitory phase that will be replaced someday with a better form of life. If there is a fundamentally different form of life to come - perhaps a spiritual form - different physical laws may be required.

And supposing that the universe is entirely natural, if the physical constant alpha is evolving - however slowly, by our standards - other principles of physics may be evolving too. Perhaps in an entirely natural universe, the far future may include forms of existence not possible under current physical law, such as a naturally arising spiritual plane.

In either case, the "alpha" finding reminds us that the human quest to understand the universe is only in its infancy. There is so much about the heavens we don't know - and so many reasons to feel filled with wonder.