The outer solar system continues to confirm the biblical timescale. When the New Horizons spacecraft flew past the Pluto system in July 2015, its findings challenged secular expectations. In the standard old-universe model, Pluto formed about 4.5 billion years ago. Yet, New Horizons found evidence of a geologically “youthful” surface for both Pluto and its largest moon Charon. A recent study examining the sparse cratering on these worlds provides even additional evidence of their biblical age of a few thousand years. To understand this, we need some information about comets.
Comets are evidence that the solar system is much less than a million years old. They are balls of various types of ice and dirt. Their main constituent is water-ice. But frozen carbon monoxide is also a significant component, with smaller amounts of ice of carbon dioxide, methane, and ammonia. Comets generally have highly elliptical orbits, spending most of their time far away from the sun in the outer solar system. But their orbit briefly brings them into the inner solar system where their icy material is heated by the sun.
The light and heat from the sun causes the outer layers of the comet’s surface to vaporize, forming a visible cloud of dust and gas called a coma which surrounds the comet’s icy nucleus. Solar wind and radiation pressure exert a force on the dust and gas, forming a tail that points away from the sun. So comets constantly lose mass that is carried away in their tail. Every time you see a comet, it is losing material. The visible tail can extend millions of miles into space. However, the source material is contained in the comet’s nucleus, which is typically only a few miles across.
Astronomers classify comets into two categories. Short-period comets have an orbital period of less than two hundred years. They are usually prograde (they orbit in the same direction as the planets), and are generally roughly in the same orbital plane as the planets. Conversely, long-period comets have a period of at least 200 years with some exceeding several thousand years. Long-period comets have a random orbital inclination (not generally in the same plane as the planets), and about half of them orbit retrograde (opposite the direction of the planets).
Comets pose a problem for the secular timescale. Since the nucleus of a comet is only a few miles across, and since we can measure the rate at which material is depleted, we can estimate the maximum age of a comet. This number comes out at around 100,000 years. After this time, the comet would be completely depleted of all its material, and would cease to exist. For comets with a short period, that number is even smaller. In fact, we have directly observed the complete destruction of comets by solar heating. For example, comet ISON, discovered in 2012, no longer exists.
The Kuiper Belt and Oort Cloud
Since comets cannot last anywhere close to the secularist-assumed age of the solar system of 4.5 billion years, secular astronomers believe that there must be a source of new comets – a “comet generator.” And since there are two distinct types of comets, secular astronomers have invented two distinct comet generators. Jan Oort proposed that a spherical mass of trillions of icy objects surrounds the sun at a distance of 2000 to 15000 times farther than Earth orbits. The idea is that occasionally one of these icy objects from this “Oort cloud” is injected into the inner solar system, becoming a brand-new long-period comet. So as comets are destroyed by the sun over time, the Oort cloud is thought to replenish them. Of course, at such a distance, we cannot detect any evidence of an Oort cloud with current technology. It remains a conjecture.
Astronomers proposed a similar solution to resupply short period comets. Named after Gerald Kuiper, the Kuiper belt was hypothesized to be a disk of hundreds of millions of comet-sized ice balls orbiting just beyond Neptune and extending to about thirty times that distance. Again, the concept is that the objects in this disk are occasionally injected into the inner solar system to become brand new short-period comets.
The Kuiper Belt Found! …or Was It?
In the 1990s astronomers began to discover objects at a distance beyond Neptune. These are sometimes referred to as “trans-Neptunian objects” (TNO) – a fitting name. We have now discovered over one thousand TNOs. These discoveries led to the reclassification of Pluto as the largest member of the TNOs. Some astronomers have taken to calling these Kuiper belt objects (KBO). Is the problem of short-period comets solved?
The difficulty is that these TNOs are not comet-sized. They are much larger – typically hundreds of miles in diameter. This is over ten times larger than the largest known comet nucleus, which means they are at least a thousand times more massive! Further, the color of TNOs does not generally match that of comets, which may suggest a compositional difference. In particular, TNOs with low orbital inclination are redder than comets, which challenges the idea that the former become the latter.
We may well refer to this region of the solar system as the Kuiper belt since this is just a matter of terminology. But my point is that the observed objects in the Kuiper belt do not solve the (secular) problem of short-period comets in an allegedly old solar system. Secular astronomers assume that hundreds of millions of comet-sized objects are indeed in this region, but have simply evaded our detection due to their small size. In other words, we can only detect the anomalously large ones. This is where Pluto comes in.
Cratering on Pluto and Charon
If hundreds of millions of comet-progenitors have been orbiting in the outer solar system for billions of years, then many of them would have impacted on Pluto and its largest moon Charon. The surface of these distant worlds should be nothing but craters on top of craters on top of craters. Geological activity might erase craters on worlds like the Earth, but Pluto is far too small to retain internal heat for billions of years to power any recent geology. So secular astronomers were expecting Pluto and Charon to be covered with craters.
But when the New Horizons spacecraft transmitted images of these worlds, we saw relatively few craters. One region of Pluto called Sputnik Planitia had no craters at all! It showed a pattern of polygonal tiling indicative of convection, which requires heat – recent geological activity. This is powerful confirmation of the youth of Pluto, which cannot retain heat for billions of years due to its small size. But even areas of Pluto and Charon that do not show recent geologic activity are nonetheless relatively sparsely cratered. How can this be if they have been impacted by Kuiper belt objects over billions of years?
Furthermore, a recent study has shown a deficit of small craters in particular. Craters less than 10 miles in diameter are particularly rare on Pluto and Charon. Why is that strange? Well, if there are hundreds of millions of comet-sized TNOs orbiting in the vicinity of Pluto, then these small-scale craters should be the most common. So where are they? At the least, this suggest that smaller TNOs are less common than required for them to resupply the inner solar system with comets. As creationists, we would expect some cratering since the Pluto system has been around for thousands of years, and since God may have used some process in creating these little worlds. In light of the biblical timescale, we might expect evidence of recent geological activity like that in regions like Sputnik Planitia. Once again, the evidence matches our biblical expectations.
 There are some exceptions. Halley’s comet is a short-period comet that orbits retrograde – opposite the direction that the planets orbit.
 Singer, K.N., et al., Impact craters on Pluto and Charon indicate a deficit of small Kuiper belt objects, Science Vol. 363, Issue 6430, March 1, 2019.