How Old Is the Solar System?

How Scientists Determine Its Age

by Troy Lacey on December 3, 2019
Featured in Answers in Depth


In a recent ARJ, Dr. Danny Faulkner examined the 25 most popular solar system astronomical models that Young Earth Creationists (YECs) use to argue for a recent creation and young universe. When considering the question “how old is the solar system,” he concluded that some of the arguments need to be discarded, while others need to be updated or expanded. A few are robust, but YECs must continue to research, refine, propose, and/or develop new arguments.

The Good

Lunar Ghost Craters

The moon has thousands of impact craters, most of which are in the highlands. Very late, large impacts produced impact basins and prompted lava flows that partially filled these impact basins. Because the lower impact basins were smoother and darker than the highlands and looked like an ocean, these regions were called maria.

Ghost craters appear as faint circular outlines in the otherwise smooth-looking lunar maria, almost like a road pothole that has been tarred over, but the outline of the “crater” remains barely visible. Since the ghost craters were modified by the volcanic overflow that formed the maria, those craters predated the volcanic overflow. But the ghost craters had to have formed after the impacts which caused the lava flows. This cause-and-effect suggests a very short time between the creation of impact basins and the subsequent volcanic overflow. And because of the large number of still-visible ghost craters, this argues for a recent origin and is still a viable young solar system evidence.

Lunar Recession

In short, this is a calculation by YECs of the moon’s rate of recession from the earth, showing the moon’s association with the earth cannot be more than 1.5 billion years old, which is much less than the 4.5 BY secular calculation. This is still a good argument to use in support of a young solar system. Click on this article for more information.

Heat Loss from Jovian Planets

Three of the four Jovian planets (Jupiter, Saturn, and Neptune) emit far more radiation than they receive from the sun (Uranus does not). There really are only two possible explanations: (a) the planets are radiating primordial heat or (b) these planets are undergoing settling, with denser material falling to greater depth and generating energy in the process. But both processes would have maximum time constraints much less than their proposed 4.5 BY existence. So either one or both of the above processes are good arguments for a recent origin of those three planets (and a young solar system).


It is well known that individual comets have lifetimes far less than the supposed 4.5 billion-year age of the solar system.

It is well known that individual comets have lifetimes far less than the supposed 4.5 billion-year age of the solar system. This “lifespan” is limited by evaporation, collision, or ejection from the solar system, and even best estimates yield only a few million years at most for any given comet. There are two types of comets: short-period (orbital periods of < 200 years) and long-period (>200). Short-period comets tend to have relatively circular orbits around the sun and orbit in the same direction (prograde) planets orbit the sun, counter-clockwise as viewed from above the earth’s North Pole. Long-period comets tend to have highly elliptical and inclined orbits and can orbit prograde or retrograde.

Since comets have a short lifespan (as compared to the supposed evolutionary age of the solar system), and they still exist in great numbers, in a long-age cosmology, there must be continual replenishment. The Oort cloud has been proposed for long-term comets and the Kuiper Belt for short-term comets. There is no evidence for the Oort cloud, and evidence for the Kuiper Belt amounts to the detection of trans-Neptunian objects, which does not necessitate a Kuiper Belt. In any case, comets remain a good argument for recent origin.

Earth-Crossing Asteroids

Asteroids whose orbits cross earth’s orbit introduce the potential for collisions. Such impacts would produce significant craters that should leave tell-tale traces. There have been several such fossil impact craters identified on earth, however much fewer than would be expected in a 4.5 BY old solar system.

The Bad

Dr. Faulkner discourages the use of those young-age indicators that do not survive scrutiny. He also urged biblical creationists to be vigilant in keeping up with new developments that may affect even the good arguments.

Dodwell Hypothesis

The earth’s axis is an imaginary line that runs from the north to the south pole, but the earth is tilted from the perpendicular regarding its orbital axis, currently at about 23.4°. This axial tilt is the reason that the earth experiences seasons, and astronomers usually call the earth’s axial tilt the obliquity of the ecliptic. It has been well known to astronomers that this tilt changes slowly over time (due to gravitational forces of the sun, moon, and planets). So, over the past 2,000 years, astronomers have taken and recorded measurements of this change.

Australian astronomer (and YEC) George Dodwell (1879–1963) collected measurements from various ancient and medieval sources and also computed the earth’s obliquity from stone structures that act as “sundials” like Stonehenge and Karnak. Dodwell assumed that the earth originally had a nearly 0° tilt before the flood. Using the data he gathered, he then computed that the earth had been hit by a large meteoroid at 2345 BC +/- 5 years, which then caused the axial tilt to shift to the ~23° tilt we have today. Many creationists readily accepted Dodwell’s hypothesis because of the timing of his impact estimate. But Dodwell uncritically relied upon secondary sources and was neglectful or extremely careless with his data and margins of error in others’ and his own calculations. For these reasons, the Dodwell Hypothesis is not viewed as a good Young Earth or Solar System argument.

Lack of Meteorites in Geologic Strata

The second argument examined was the preponderance of meteorites on the earth’s surface, with relatively few being found in sedimentary layers. Surface meteors must have obviously fallen in relatively recent years (even in geologic terms this would be from the Holocene (< 10,000 years). However, in a flood geology paradigm, we would expect to find very few meteorites in sedimentary strata, because most strata were laid down rapidly, within a few months to a year at the latest. But creation geologist Andrew Snelling has reported on a meteorite shower field in Ordovician limestone, and several creation geologists and astronomers have postulated meteors as a primary catalyst for the onset, or other early stages of Noah’s flood. This and the fact that little research has been done in this area render this method unhelpful unless new data clearly revives it.

Lunar Dust

This argument goes back to the late 1950s when the US Government was looking at the feasibility (and dangers) of landing a manned craft on the moon. Estimates of meteorite dust falling on the earth were extrapolated to the moon, and there was a concern that the moon may have several feet of dust on the surface. When unmanned US spacecraft (Surveyor 1¬–7 from May 1966 – January 1968) began to land on the moon, it became clear that lunar dust was only inches thick, which gave NASA confidence for later manned missions.

But with only inches of dust on the surface, this began to be used as an evidence of a young solar system. The problem with the argument then and now is that the dust measurement usually quoted in support of the argument by young-earth proponents from a 1960 Pettersson paper and is generally regarded as high (possibly 100 times too high!) by even secular scientists. Since the exact measurement of meteorite dust falling (and collecting) on the moon’s surface is unknown, to us, this argument is not a good one.

Rock Flow on the Moon

This is actually an old-age counterargument, stating that lunar rock viscosity was so low that it would cause crater edges to flow downhill and therefore dissipate over thousands or millions of years. But the secular measurements from this 1983 paper were way off, not just on lunar rocks, but on earth rocks as well. This old-universe counterargument does not hold up.

Mercury’s Atmosphere

Mercury does appear to have a thin atmosphere, but the majority of the elements making up this atmosphere are much heavier than the primarily nitrogen and oxygen atmosphere of the earth. Original estimates of Mercury’s atmosphere were that it was 98% helium and 2% hydrogen. Creationist Theodore Rybka then argued that these lighter elements making up Mercury’s atmosphere, proved that Mercury was young. But a few years later, more precise measurements of Mercury’s atmosphere emerged from the Mercury Messenger mission (2011-2015). While there is a small amount of oxygen and hydrogen in Mercury’s atmosphere, there is even less nitrogen and Helium. The most abundant two elements are sodium and magnesium. Lighter elements which occur in trace amounts may be brought in by the solar wind. Therefore, using Mercury’s atmosphere as evidence of a young age is unwarranted.

Tall Mountains on Venus

It has been argued that there should be no tall mountains on Venus if the planet were billions of years old. Since Venus, like earth, has a plastic (viscous liquid/solid) upper mantle, dense landforms should eventually sink back into the mantle. However, as in the case of Maat Mons, a 5.5-mile-high (9 km) mountain, it shows clear evidence of recent volcanism, which means that the mountains on Venus (if volcanic) may be young, but using them as evidence for a young planet is not a valid argument.

High Winds on Venus

Another recent argument for a young solar system was that the high winds in the upper atmosphere of Venus are opposite to the direction of Venus’ rotation. If this were the case, then friction with the surface should have effectively negated the wind speed over a short time period. But in this case, the reasoning was incorrect because the calculations were done based on Venus having a prograde rotation. Since Venus (along with Uranus) have retrograde motion, the winds actually run in the same direction of Venus’ rotation.

Dust Storms on Mars

Another postulation put forth was that dust storms raging across Mars frequently are evidence of a young, dynamic planet. But differential heating, a result of the extremely thin Martian atmosphere, can cause temperatures to swing anywhere from 70ºF (20ºC) near the equator in summer, down to -195ºF (-125ºC) near the poles in winter. That could easily account for Martian dust storms, and therefore it is not a valid argument to use for a young age.

Lifetimes of Certain Asteroid Orbits

The asteroids 2060 Chiron and 944 Hidalgo have paths that take them by Jovian planets, so they are exposed to severe gravitational tugs. Therefore, their existence in their current orbits suggests that they have been in those orbits far less than billions of years. But a secular astronomer would counter that in the past they were perturbed from previous orbits into their current ones.

High Winds on Jupiter and Saturn

It was also suggested that high winds on Jupiter and Saturn were evidence of a recent creation. But both planets receive significant heat from their interiors, as well as solar heat. In addition, because of their size (compared to earth) combined with their rotational speeds, which are much faster than earth’s, the Coriolis effect in their atmospheres is much stronger than on earth. Between all these factors, there is too much uncertainty about their planetary dynamics. It is not a good argument to suggest that high winds on Jupiter and Saturn are pieces of evidence of a young solar system.

It is not a good argument to suggest that high winds on Jupiter and Saturn are pieces of evidence of a young solar system.

Hydrogen in Titan’s Atmosphere

Titan has an appreciable atmosphere. Even with far less mass and less surface gravity than the earth, Titan’s atmosphere is more substantial: mostly nitrogen and methane, with only <0.2% hydrogen. One creation argument was that because of no satisfactory mechanism for manufacturing hydrogen, there should be none in Titan’s atmosphere if it were old. But solar ultraviolet light and energetic charged particles in Saturn’s magnetosphere and cosmic rays are possible mechanisms for producing hydrogen by breaking down organic molecules. So, this particular young age argument is not valid.

The Orbit of Triton

Neptune’s satellite has a retrograde orbit (opposite of its planet’s rotation). Triton also has an irregular inclination, but an almost perfect circular (near zero eccentricity) orbit. All of these characteristics together are not found in any other planetary satellite. One creation argument for a young age was based on Triton’s orbital decay, which was considered to be high (meaning it would collide with Neptune within 100 million years maximum). Still, recent measurements have changed, and the orbital decay is now listed as 3.6 billion years.

More Research Needed

Dr. Faulkner encouraged further discussion of some of these existing young-age arguments.

Transient Lunar Phenomena

Considered to be near 4.5 billion years old and having a much lower density than the earth, the moon is deemed geologically dead, meaning no active volcanism. Yet there are constant sightings over the past 50+ years of transient lunar phenomena (TLP’s). These can be flashes of light, cloud-like patches, or changes in the color of the lunar surface as viewed through telescopes. To date, there has been no satisfactory answer to TLPs. But since a geologically active moon would drastically lower its age estimate, scientists have basically ignored TLPs and written them off as some type of anomaly. However, if the TLPs are legitimate and are caused by lunar volcanism, then this could still be a good young solar system argument. More research is needed, though.

Mars’ Moons

Phobos is the innermost of two small satellites (moons) that orbit Mars. Its orbit is decaying, and it is being pulled closer to Mars. But Deimos, the outermost moon, is actually receding from Mars. Both satellites have nearly circular orbits, which is not expected for captured satellites. Since Phobos and Deimos are considered to be captured asteroids, in the cosmic evolutionary paradigm, why are their orbits not wildly elliptic? This orbital issue of Phobos and Deimos may provide a good argument for a recent origin after all but needs further study.

Volcanism on Jupiter’s Io

Io is considered to be one of the most volcanically active bodies in the solar system. Because it is much smaller than Jupiter, its heat-loss rate would be much greater. Secular scientists have proposed tidal flexing (rather than primordial heat) as a possible heat-generating mechanism, but this ad-hoc proposal also fails to measure up.

Cryovolcanism on Enceladus and Triton

Saturn’s satellite Enceladus and Neptune’s satellite Triton both have cryovolcanoes, which emit water, methane, or ammonia rather than magma or sulfur. In both cases, the problem of primordial heat to drive these eruptions places a young age cap on these satellites. Tidal flexing was again proposed for Enceladus, but even secular literature has criticized this idea. Both Enceladus and Triton’s cryovolcanism are good young-age pieces of evidence, but more research needs to be done on these two satellites.

Methane in Titan’s Atmosphere

Solar radiation converts methane into other hydrocarbons. The time required to do this is about 50 million years, so there should not still be methane in Titan’s atmosphere. Secular cosmologists have proposed that methane produced on Titan replaces that which is lost continually. However, creation cosmologists have argued that Titan’s geological processes are inadequate to replace methane at the level it needs to maintain any in the atmosphere.


Pluto and its satellite Charon have revealed several surprises since the New Horizons mission flew past in July 2015. Some of those surprises are lack of craters on both bodies, a light-colored region on Pluto that demonstrates recent icing, high mountain ranges on both, and Pluto still having a thin atmosphere. All of these were unexpected in an old-age cosmology. More study is needed on these features of Pluto and Charon, and while not conclusive yet, they might be good evidence of young age.

More study is needed on these features of Pluto and Charon, and while not conclusive yet, they might be good evidence of young age.

Planetary Rings

All of the Jovian planets have rings, although Saturn’s are the largest in number and the most visible (even with low-power telescopes) and well known. The 1970s-late 1980s Voyager flyby missions and the orbital Cassini missions (1997¬–2017) documented substantial changes in the Jovian planets’ rings in a relatively short time. Secular cosmologists propose that the rings of these planets are constantly forming, eroding, and then being formed again by the capture of an asteroid or perturbed satellite. Once the asteroid gets within the Roche limit, it is destroyed by the planet’s tidal forces. (The Roche limit is the closest distance that a satellite held together only by its own gravity can come to a planet without being pulled apart by the planet's tidal (gravitational) force).1 The shattered asteroid then orbits the planet. But this scenario would have to play out thousands of times for the planets to maintain a ring system. Secular cosmologists must concoct a system where suitably sized asteroids are constantly being recycled into rings and eroded away. The only alternative is that we just happen to be living at a time when all four Jovian planets have ring systems. The study of how planetary rings form, erode, and even how they become dirty (icy parts become dust-covered) needs to continue to be monitored. But this appears to be a good argument for a recent origin of the ring systems at least.

Poynting-Robertson Effect

Briefly, this known effect states that dust particles smaller than 10 micrometers are blown away from the sun by solar winds, and those larger are pulled towards the sun and eventually burned up. A pair of creation astronomers running the numbers found that within two billion years, all dust particles less than 188 µm diameter within the earth’s orbit should have been removed. They also calculated particle sizes needed for removal from Jupiter and Neptune’s orbit within two billion years. Needless to say, dust particles of that size still remain in a supposedly 4.5 BY solar system. However, the secular response was that as dust is removed from the solar system, it is replaced by dust produced by collisions of planetesimals and the disintegration of comets. Since recent years have produced a much greater number of known comets and planetesimals, the secular argument is potentially plausible. Still, the Poynting-Robertson Effect is not widely discussed in secular models. Consequently, more research needs to be done in this area, and this still may be a good young-age argument.

Dispersion of Meteor Showers

Comets are delicate objects, losing many small, solid particles with each passage around the sun, often leaving a trail of debris behind them. The earth experiences meteor showers (actually comet debris) as it crosses the orbits of various comets and their debris trails enter the earth’s atmosphere. The Poynting-Robertson effect (discussed above) ought to segregate meteoroids (pebble to one-meter-wide rocky or metallic debris) within a meteor shower trail according to size on a relatively short timescale, yet this is not commonly observed. Consequently lack of segregation may indicate recent origin—however, the addition of new particles as comets continue to shed them complicates the calculations. A detailed analysis of the processes involved is desirable, but in the meantime, this may be a good indication of recent origin.


Creation scientists (and those in training!) are urged to seek out the development of new arguments for a recent origin of the solar system. This type of admonition and exhortation to search out the workings of God’s creation is one which is modelled in Scripture and one which we should listen to.

An intelligent heart acquires knowledge, and the ear of the wise seeks knowledge (Proverbs 18:15).

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  1. Roche limit ." The Columbia Encyclopedia, 6th ed. Accessed November 22, 2019.


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