One of the questions that comes up at this time of year is "What was the star of Bethlehem?" That is, "How should we understand the phenomenon referred to in Matthew 2 as a 'star' that guided wise men out of the east to the place of the young Messiah?"
The modern scientific materialist has a couple of options. He may discount the account altogether, or he may seek some strictly natural explanation that explains the event and explains away the idea that it had anything to do with the appearance of God in human form.
We'll talk about strictly natural explanations in a moment (since it is an option available to the theist as well). But we can dismiss the materialist view itself, because it is an inaccurate understanding of the world in which we actually live. The term 'scientific materialist' frequently misleads folks; it is not a scientific view, one arrived at by consideration of the scientific evidence. Instead, it is a metaphysical view (a religious one), involving belief a priori (that is, 'before the evidence') that nature is the whole show and that there is no God.
But both the evidence and reason lead away from that view, confirming instead the Judeo-Christian understanding of the universe. To put it another way, scientific discoveries--and especially the biggest discoveries of the past century--powerfully confirm the metaphysical claims contained in the Bible, many of which anticipated those dicoveries by thousands of years.
This Bible--unique among the world's holy books in this scientific accuracy--tells us several important things. Besides the fact of the existence of a Creator/Sustainer that is transcendent to (outside of the time and space of) the creation, Scripture tells us to study the creation itself to learn about that God. And both that study of the creation and the Scriptures themselves tell us that God is not merely transcendent but also immanent. By immanence is meant that He actual enters in to, supernaturally intervenes in, that creation. Such supernatural intervention is usually given the term 'miracle,' and the star over Bethlehem is generally considered to fall into that category.
[By now, some of my readers are becoming exasperated by my taking the long way around to answer the question. "Just tell me what you think the star was!" they are saying. But I'm hopelessly big-picture, and feel the need to put that answer in its larger context, and, well, it's my blog, so they'll just have to hang in there while I do that, or move on in their impatience.]
Now, given all that--that we live in a world accurately described by the Judeo-Christian Scriptures, one created and sustained by a transcendent yet immanent God--we can rightly go on to distinguish between two categories of miracles.
First, there are those miracles in which God uses strictly material things (that He previously created) and purely physical laws (that He already put into place). In such instances, the only supernatural aspect of the event is the fine-tuning, the timing and/or location, of it. The evidence (from science and Scripture) indicates that many of God's miracles have been of this type.
Generally, the question "What was the star of Bethlehem?" has in view this category of miracle. The person posing the question usually means, "Is there some well-documented physical phenomenon, some understood physical laws, that can be invoked to explain the account in Matthew 2?"
And for the person looking for such an answer, many options exist. This is in part because the Greek word aster, which is translated 'star' in the gospel account, has a broad range of potential meanings. That is, objects and events that in English are distinguished among by the terms star, planet, conjunction of planets, meteor, comet, and supernova all would be covered by the single Greek word translated star. And each of these things has been proposed as the explanation for the star of Bethlehem. Most can be quickly dismissed for a variety of reasons, each presenting problems even for the scant textual evidence that is given us.
In my opinion, the most likely explanation (from within this category of miracle) is that the star may have been a recurring nova. Novae are the explosions of stars as they die. And a small percentage of such explosions occur in stages, such that the initial explosion (resulting in a period of great brightness that may last weeks or even months) may be followed (after a period of dimness) by a second explosion. Such an event could be reconciled with the star seen (according to Matthew 2) in the east, and later as the wise men neared Bethlehem.
But there's a second category of miracle that should be mentioned. This category encompasses those cases where God does not limit Himself to already-created material and established physical laws, instances where (as is His perogative) He actually suspends those laws for His good purposes.
Take, for example, the story of Jonah in the belly of the whale. There have been those Christian apologists who have sought to allay the incredibility of this miracle by finding similar, natural examples. They posit a baleen whale (the large species without teeth that filter krill and other tiny organisms from the water), and look for records of such a whale engulfing, say, a sea otter, which was subsequently released unharmed when the whale once again opened its jaws. I consider this approach misguided. It seems to miss the main point, which is that however much natural material was involved there was something very supernatural that went on.
Or take a more obvious example, the account of Yahweh speaking to the false prophet Balaam through the mouth of an ass. Is it clear that I would be wasting my time if I searched for a race of donkeys with a wider vocal repertoire than the ones with which we are familiar, in order to try to make this Old Testament account more palatable to folks in a modern scientific age? If we really take this account seriously, we acknowledge that in this one instance God suspended the natural laws that He put in place (those governing the vocal capacities of equines), and did something supernatural.
The same could easily be true of the star of Bethlehem. Perhaps the light guiding the shepherds cannot be understood as a natural phenomenon (even with supernatural timing) of this universe. It could be that God provided a supernatural, other-worldly light on this one occasion for His own purposes.
We may never be able to answer this question with any certainty, to avow that the star in question was a recurring nova (or some other natural event with miraculous timing and location) or, on the other hand, that it was almost certainly entirely supernatural. But while it is God Himself who gives us our native curiosity about such issues, the important thing is that we recognize and acknowledge that it is He who is sovereign over this world, and He who can intervene when and how He chooses, that it was He who, about 2000 years ago, made a way of reconciling the world to Himself through the Baby born at the other end of that star-guided journey.