Enceladus: How to Keep a Young Moon Looking Old

It looks young. But
assumptions can keep
it billions of years old

I read the following paper with great interest, because I was at JPL working in the Cassini Program when its active geysers were discovered in 2005. The ~100 supersonic jets of water ice blasting out its south pole ranks as one of the most surprising discoveries of the Cassini Mission, if not of all planetary science. How could a tiny moon be this active?

The discovery was so important and exciting, the Cassini Team planned 20 additional flybys of the little moon that ejects so much material, it creates its own ring around Saturn! (the E-ring). Cassini navigators even flew through the geyser plumes to collect samples of the ejecta. It was mostly water ice, with traces of sodium, minerals, and trace amounts of carbon.

The Enceladian crater production function (Wong, Werner, Kirchoff and Brasser, Icarus, 1 January 2027). E. W. Wong and M. R. Kirchoff did the bulk of the work on this detailed paper. For the last decade, they have been counting, measuring, and classifying 16,958 craters on a moon only 300 miles across, the width of Arizona. Their goal was to produce a Crater Production Function (CPF) that “makes no assumptions about the impactor source population or planet evolution models or the timing of impact,” letting the data drive the conclusions. Although they only suggested a possible sequence of events, they hope their CPF will be an aid for further research. “A corresponding improved model crater chronology for Enceladus will be presented in a forthcoming paper,” they promise.

Over the 13 years of the mission, the Cassini team gathered more information on Enceladus than any other Saturnian moon beside its giant sibling, Titan. Ever since those exciting days, CEH has been reporting follow-up news about Enceladus, showing that so much activity in a tiny moon challenges assumptions of deep time (see here, here, here, and here, or search on Enceladus in the search bar).

What Needs Explaining

From the photos selected for this paper and from my previous awareness of the mission photos, I knew about craters bisected by viscous flows, parallel troughs cross-cutting adjacent craters, other troughs and ridges making sudden turns, large craters that had relaxed to look like melted ice cream, pit chains apparently formed by low-inclination impactors, large areas nearly free of craters, other regions that were heavily cratered, and, of course, the complex “tiger stripe” terrain at the south pole where the geysers jet out at supersonic speed from a presumed subsurface ocean.

Note: We should ignore the frequent hype from bio-astrologers that life might have evolved in its comparatively warm but still frigid waters in the dark. That is silly.

Anyone reading this paper can admire the detailed effort and the information that Wong and Kirchoff add to the literature on Enceladus, building on dozens of previous papers and extending the database of knowledge. Their desire to pursue a data-driven, assumption-free CPF is also admirable. As we shall see, the assumption of deep time crept into the work anyway.

Identifying craters on Enceladus is not always easy. Big craters are obvious, but for many others, identification is limited by the following factors:

• The resolution of Cassini’s cameras
• The distance to a terrain being surveyed, which differed by region
• The sun angle; overhead light washes out shadows
• The camera angle: a shallow angle can make a circular crater look ellipsoidal
• Possible latitudinal differences between cratering at the equator vs at the poles
• Tectonic features that can mimic a crater: “distinguishing craters from tectonic features of similar scale can be challenging,” they admit.
• Craters partially erased by viscous relaxation
• Craters partially erased by geyser fallout or “snow” from the E-ring
• The missing history of saturated regions overprinted by newer craters
• Unknown relationships between heavily cratered regions and smooth regions

These and other complications were not ignored by the authors, but they inevitably introduce the bugaboo of scientific explanations: interpretation.

An Admirable Effort, but with Recognized Limitations

To minimize interpretations to some degree, they subdivided the four previously-chosen geological domains on Enceladus:

“we subdivided Enceladus’ surface into 62 analytical units (Fig. 3) based on three simultaneously considered criteria: (i) large-scale geomorphological structures — ridges, troughs, and surface texture transitions (Section 5.1.2); (ii) spatial variations in crater density, reflecting differences in resurfacing history and solidification age (Section 5.1.3); and (iii) imaging properties, particularly image resolution and solar incidence angle, to prevent instrumental artefacts from being misinterpreted as geological signals.”

Notice that criterion (ii) involves assumptions about age (see list of unknowns below).

Other restrictions were placed on the data used for analysis:

Units exhibiting significant surface modification, such as partial resurfacing or preferential loss of small craters, were excluded. Secondary craters were not considered, as their expected sizes fall below the effective resolution of available Enceladus imagery.

They further restricted their counts to craters 200 meters or larger across to stay within the resolution limit of the imaging subsystem (ISS). This arbitrary limit necessarily omits much of the data that might inform the history.

They also ignored the problem of secondary craters (fallback debris from an impact), assuming that secondaries would be much smaller and reside nearby large craters. This is not necessarily true (see 30 Oct 2018). Previous work also showed that secondary impactors can move between moons or even between planets, so their assumption that secondaries can be identified on Enceladus by their size and proximity to a primary crater cannot be justified. A swarm of secondary impactors from a neighboring moon, or from another planet, could potentially create numerous craters on Enceladus in a short time. A comet breaking up could do the same, as Comet Shoemaker-Levy 9 showed in 1994. How would anybody know without witnessing what actually happened?

They admit limitations of their analysis:

By leveraging global coverage and unit-to-unit comparisons, the resulting CPF provides a more robust and internally consistent framework for future age-dating applications on Enceladus and other icy satellites. We note, however, that crater relaxation driven by viscous ice flow and crater floor infill by E-ring material cannot be fully quantified, as Enceladus’ historical heat flux and long-term south polar plume deposition rates remain poorly constrained. These processes therefore represent recognised limitations of the present analysis.

No Model Is Assumption-Free

Nevertheless, the authors boast that “The CPF is derived directly from crater counts instead of model-based predictions.” Sticking to the crater observations alone, though, is it really possible to determine a credible Crater Production Function (CPF) in light of these points of interpretation? How well can readers trust the authors’ opinions?

1. Nobody witnessed the history of Enceladus: its formation, its orbital changes, or its subsequent activity.
2. Nobody has seen the subsurface ocean. It is inferred from mass spectrometry of particles captured by the Cosmic Dust Analyzer (CDA).
3. Nobody knows whether the current geothermal activity is anomalous, periodic, or in steady state.
4. Nobody knows how long the current heat flux from the geysers (-150 megawatts per square meter) has been operating.
5. Nobody knows the deposition rate of fallout from the south polar plumes.
6. Nobody saw the source of impactors, their nature, their population density, or their material density (e.g., fluffy or rigid)
7. Nobody witnessed changes to the impact rate over time.
8. Nobody can certify that methods used to interpret surface ages for the Moon or Mars are valid for Enceladus.

The authors apparently did not consider CPFs for the neighboring moons Mimas (on the inside orbit) or Tethys (on the outside), which should have experienced a similar impact history. That would seem a vital control for testing their interpretation of crater production on Enceladus.

See also our previous articles on the inherent limitations of crater count dating.

A Bit of Cognitive Dissonance

At a couple of points, the authors seem to admit that Enceladus cannot be as old as Saturn. Notice some special pleading in this quotation:

Under a constant heat flux of 150 mW m⁻² on a 150 K surface, craters 15–20 km in diameter with depth-to-diameter ratios of 0.2 could relax by over 80% . Specifically, at a current maximum equatorial deposition rate of 10⁻³ mm yr⁻¹, these craters could be buried within a few hundred million years. Although a constant heat flux is unlikely, this relaxation timescale could still be achieved with transient periods of extreme heat flux and higher deposition, e.g., due to a shift in the locus of plume activity. Ongoing work continues to refine models of historical and current heat flux and deposition.

Why, then, have they not relaxed completely in 4.5 billion years? A few hundred million years is just a fraction of the assumed age of Enceladus (4.5 billion years). The authors interpreted this difficulty in a way that rescues deep time.

Here is another example of admitting youth but explaining it away to maintain deep time:

Multiple lines of evidence, including active degassing and physical libration, point to the presence of a subsurface ocean (Thomas et al., 2016, Nimmo et al., 2023). However, the internal heat required to sustain this activity exceeds expectations from tidal dissipation and radiogenic heating alone (Meyer and Wisdom, 2007, Roberts and Nimmo, 2008). Together with the coexistence of heavily cratered and smooth sparsely cratered terrains, this indicates a complex and evolving geological history. Constraining the timing and duration of this activity through robust surface age estimates is therefore essential.

What could possibly turn the geysers on and off at different times? There’s one thing that works for any occasion: Imagination. Everything evolves, including the history of this little moon and the interpretations required to support the narrative. Enceladus must be kept old.

I want young earth creationists to face up to our own difficulties. Clearly Enceladus had a history. Thousands of craters testify to that history, along with troughs, ridges, and evidence of viscous flows on the surface. Can these be fit into a Biblical timeframe, which is shorter than the evolutionary timescale by six orders of magnitude?

I believe that they can, because the Bible is our ultimate authority. Here are some points to ponder:

• • Evidence does not interpret itself.
  • Historical science operates differently than observational science.
  • Upper limits are easier to justify than lower limits (see 8 Aug 2015 commentary).
  • Deep time is a bigger problem for scientific materialists than youth. A tiny moon like Enceladus could never maintain its activity for a few million years—let alone 4 billion. Everybody agrees the geyser activity makes this tiny moon look far younger than Saturn.
  • Enceladus is not the only age problem for evolutionists. Titan, Mimas, Saturn’s rings, and other features throughout the solar system cannot be as old as claimed. Search our category “Dating Methods” to see many examples on Earth and other planets and moons.
  • The Earth has a much more complex geological history than Enceladus, yet creation scientists have multiple lines of evidence to show it is young (example 1, example 2).
  • If all these things are as young as the evidence indicates, deep time is falsified, and other interpretations must be allowed into the debate.

Look at the list of points of interpretation above (“No Model Is Assumption-Free”). Nobody witnessed those things. We didn’t either. Mr. Nobody is the only one who knows, but he won’t tell. We have on good authority Somebody who does know, and he did tell: the Eyewitness of creation—the Creator himself, who cannot lie. The straightforward reading of Genesis indicates it was on the order of thousands of years ago, not millions or billions. If mainstream scientists can resort to special pleading to cling to their previously-assumed timeline, then we can do no worse. Interpretation is baked into the process of modeling unobserved histories. Don’t shy away from it. Embrace it with the best evidence and logic, and be up front about your assumptions. Then present a best case scenario consistent with the observations.

Geological processes do not require millions of years. We have seen that repeatedly on Earth, like at Grand Canyon and Yellowstone. Let creation planetary scientists, physicists and geologists take up the challenge to build a creation model of the history of Enceladus and its surface features.

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