By the Light of the Moon

John Upchurch

Does Genesis 1:15 say that the moon emits its own light?

In Genesis we read:

Let them [sun and moon] be for lights in the expanse of the heavens to give [emit] light on the earth (Genesis 1:15; NASB).

Over the years, a number of skeptics have pointed to this verse to claim that if the Bible were really the inerrant Word of God, it wouldn't make such a basic mistake as saying the moon emits light. The moon has not and does not — as far as we know — emit any sort of light. Instead, our rocky satellite simply reflects light from the sun.

While there have been a few claims that the moon does generate its own light through thermoluminescence, there really is no need to search for such exotic explanations as far as this verse is involved. In fact, a look at our own modern lexicon gives us the answer to this supposed contradiction.

Consider for a moment how earth-centric our discussions are. We say that the sun rises and sets, even though we know that the earth actually revolves around the sun and rotates on its axis. We say that the stars "come out" at night, even though we know they're always there — just hidden by the brighter sunlight. Our point of reference determines how we discuss what we see.

To us, the moon does emit light onto the earth. The sun's light strikes the surface of the moon and reflects back at the earth. Notice that the Genesis text does not say or suggest that the moon generates its own light. In fact, the point is not the source of the light; the point is the impact that the lights have on earth. One "governs" the day, and the lesser one "governs" the night (Genesis 1:16). If the moon were a light source — instead of simply a light — there would likely be no night at all for it to govern.

We can easily demonstrate this concept when we imagine someone reflecting light into our eyes from a mirror. The mirror is not the source of the light, but it does emit a powerful beam that can momentarily blind — something even biblio-skeptics would have to admit. And when such a beam is blinding someone, it is doubtful that how the light reaches the person's eyes would matter so much as the fact that it is.

Taking this verse out of context also makes it seem much more damaging, but when we step back (cf. Genesis 1:14–18), we understand more about the purpose of this passage. Other than providing light, God created the sun and moon to mark the seasons, days, and years, which they do quite well. Notice that the Bible does not provide detailed schematics and charts on how this works, since God gave humans the ability to discover these through observational science. The purpose here is not to explain all the details (though it is factually accurate and not a simplified metaphor for "primitive humans"); the purpose is to give an overview and the reasons why God did what He did. Thus, the description of the moon as giving light is not detailed, but it is quite accurate.

The real message to take from this passage is that God created two spectacular heavenly bodies that are constant reminders of His amazing power. This verse lets us (earth-centric humans) know exactly what God intended: how the sun and moon came to be and why He created them.