Is the Earth’s Magnetic Decay Proof of a Young Earth?

The decay of the earth’s magnetic field stands out as one of the strongest scientific arguments for a “young” earth.

Now, you might be wondering, what does this have to do with the biblical age of the earth? Well, if we take the current rate of decay and run the numbers backward, it becomes clear that earth’s magnetic field couldn’t have lasted millions of years. (Yes, you read that right!) This rapid decay—which is a well-documented, measurable phenomenon—has been and continues to be a major challenge to the secular belief that the earth is billions of years old. While this creates a serious paradox for secular thinking, it’s no surprise at all for biblical creationists. In fact, the evidence aligns beautifully with the biblical timeline according to the true history of the Bible! And that’s why the decay of the earth’s magnetic field stands out as one of the strongest scientific arguments for a “young” earth.1

The Role of Worldviews (Yes, They Really Do Matter!)

Before we dive into this discussion, it’s very important to understand that we interpret scientific evidence based on our worldview—the “lens” we use to view the world around us. Essentially, our worldview is a network of our most basic beliefs/assumptions, called presuppositions, that shape how we understand and interpret everything. In other words, the evidence doesn’t “speak for itself” (and if it does, you should probably run . . . because evidence shouldn’t be having conversations with you!). Despite what many people think, there’s no such thing as an unbiased or “neutral” approach to the evidence—no matter what someone tries to claim. (In fact, if a person insists they’re being neutral, that just means they’re not even aware of their own worldview!)2

As biblical creationists, we start with the presupposition that the Bible—God’s holy Word—is the true eyewitness account of history given to us by God, and thus, the earth was created around 6,000 years ago. How do we know that? Simply put, the answer comes from starting our thinking with the Bible, beginning in Genesis.3 Because we build our Christian worldview on the solid rock of God’s Word—which never changes—we interpret all evidence in light of Scripture. So when we see things like the rapid decay of earth’s magnetic field, it’s exactly the kind of evidence we’d expect to find when we build our thinking on Scripture—which confirms (not proves) the biblical age of the earth.4

On the other hand, secular scientists start with naturalistic presuppositions—assuming that the earth and the universe are billions of years old and that everything we see today is the result of time, chance, and the laws of nature acting on matter. So yes, that means their worldview deliberately excludes God and any supernatural cause from the very beginning—building their thinking on the shifting sands of man’s ideas about the past rather than the solid foundation of God’s unchanging Word. Instead of “following the evidence wherever it leads” (as many try to claim), they end up forcing the data to fit into their man-made framework. That’s why, when confronted with things like the rapid decay of earth’s magnetic field, they’re compelled to come up with elaborate explanations to keep their “billions-of-years” timeline intact—no matter how much evidence contradicts it.5

Obviously, these interpretations of the past are radically different. So the data itself cannot “prove” the age of the earth—the interpretation always depends on our starting beliefs about the past. But let’s ask this: Which worldview better matches the observable data and makes the most sense of the evidence? When we start with the authoritative Word of God and use a biblical worldview, the evidence overwhelmingly confirms the Bible.

Let’s Look at the Evidence

Since the nineteenth century, scientists have been measuring the strength of our planet’s magnetic field, and in short, they’ve observed that the field’s intensity is declining at a rate of about 5% per century .6 What does that mean? Well, if we extrapolate backward in time using this rate of decay, the magnetic field would have been exponentially stronger just a few thousand years ago. If we go back tens of thousands of years, the field’s intensity would’ve been so extreme (generating an absurd amount of heat and energy) that life on earth would’ve been impossible. Of course, it only gets worse if we try to stretch that timeline back millions of years. So yes, this deals a devastating blow to the naturalistic belief that the earth is “billions of years” old, but it’s consistent with the biblical timeline.

Back in the early 1970s, a physicist named Dr. Thomas Barnes was one of the first to analyze the decay rate, and he concluded based on the data that the magnetic field must be less than 10,000 years old—which means that the earth itself must likewise be that young.7 In a nutshell, his research showed that the magnetic field is not self-sustaining over long periods of time but instead is “running down” (like a battery losing its charge). His work has since been supported by other creation scientists, who’ve developed biblical models that explain both the origin and rapid decline of the earth’s magnetic field.8

For instance, creationists have proposed that our magnetic field is caused by a freely decaying electric current in the earth’s metallic core, meaning that the current naturally loses energy over time as it flows through the core (like electricity encountering resistance in a circuit), and this decaying current would have started when God formed the earth’s outer core. In the figure below, you can see the rapid and continuous downward trend of the total magnetic energy over time since its origin (also notice the sharp decline during the time of the global flood, which would have accelerated the decay even further due to massive geological upheaval).9

Furthermore, studies of ancient artifacts and rock samples confirm that the earth’s magnetic field was much stronger in the past. For instance, archaeological measurements show that the field was about 40% stronger around AD 1000 .11 On top of that, accurate records from the International Geomagnetic Reference Field show a net energy loss of 1.4% in just three decades (1970–2000), meaning that the field’s energy has halved every 1,465 years or so .12 Simply put, the earth’s magnetic field was created strong right from the beginning and has been decaying ever since—which, again, is a complete enigma from a naturalistic worldview but makes perfect sense from a biblical worldview. The evidence for earth’s decaying magnetic field fits very well within a biblical timeframe.

While secular scientists attribute this motion to fluid changes in the outer core, this instability of the magnetic field serves as yet another reminder that it’s anything but constant, which fits very well with the biblical view.

As a sidenote, the magnetic field isn’t just weakening—it’s also shifting. Over the last few decades, earth’s magnetic pole has been moving at an unusually fast pace, galloping toward the geographic North Pole at a rate of over 50 km/year since the 1990s.13 While secular scientists attribute this motion to fluid changes in the outer core, this instability of the magnetic field serves as yet another reminder that it’s anything but constant, which fits very well with the biblical view.

But Not Just Earth!

The evidence is not just limited to earth: Observations of celestial bodies in the solar system also challenge naturalistic assumptions and line up with a biblical time frame. Scientists now have data from space probes (like Voyager, Galileo, Cassini, and others), which show that other planets and large moons have magnetic fields that are stronger than expected under a “billions-of-years” model. To be clear, these findings don’t pose a problem for the biblical model, but they’re a huge problem for the long-age assumptions of naturalistic thinking. Here’s a handful of brief examples:

• Mercury has a measurable magnetic field, discovered by the MESSENGER spacecraft, which surprised secular scientists.14 Why? Because if Mercury is really 4.5 billion years old, its magnetic field should have been long gone by now.
• Jupiter has the strongest magnetic field of any planet in our solar system.15 (Its total magnetic strength is estimated to be around 20,000 times more powerful than earth’s field!) This was first measured by the Pioneer 10 & 11 missions,16 later confirmed by Voyager 1 & 2, and more recently confirmed by Juno spacecraft (which is currently orbiting Jupiter).17 Secular scientists struggle to coherently explain why its field is still so strong after billions of years.18
• Ganymede (one of Jupiter’s moons) has a surprisingly strong magnetic field, discovered by the Galileo spacecraft.19 Given its relatively small size, scientists using naturalistic long-age models can’t really explain how it can still generate such a field after billions of years.
• Saturn also has a strong magnetic field, first detected by Voyager 1 & 2 and later studied by Cassini.20 But what really shocked secular scientists is the near-perfect alignment of its rotational and magnetic axes (with a tilt of less than 0.007 degrees!), which is something not seen in any other planets. According to naturalistic “dynamo” models,21 such near-perfect symmetry shouldn’t exist because a small amount of tilt is required to sustain the dynamo over long periods of time.
• Enceladus (one of Saturn’s moons) has a detectable magnetic field—and even has active geysers—as discovered by the Cassini spacecraft. Obviously, this destroys the naturalistic assumption that it’s an ancient, geologically “dead” moon.22
• Uranus and Neptune both have magnetic fields, discovered by the Voyager 2 spacecraft, that do not align with their rotation axis and are offset from their center, which causes major problems for naturalistic models. Also, their unexpected strength/structure strongly challenges the belief that these planets have maintained such magnetic fields for billions of years.23

However, creationists don’t just react to data—they anticipate it with specific, testable predictions! One well-known example comes from Dr. Russell Humphreys (a creation scientist who has studied planetary magnetic fields). Using a biblical creation model, he calculated how much the magnetic field of planets should have decayed after 6,000 years. He then predicted the field strengths of Uranus and Neptune before the Voyager 2 spacecraft reached them. When the data came back, it closely matched his predictions—while naturalistic models totally missed the mark!24 This again presents a serious challenge to naturalistic thinking and strongly supports a biblical interpretation of planetary magnetism.

As expected, these findings confirm that magnetic fields across the solar system do not align with a naturalistic timeline but are perfectly consistent with the biblical one. You see, in science, a good model should be able to make accurate and testable predictions. And yet, ironically, biblical creationists are often accused of not having scientific models that can do just that. But based on these discoveries, it seems the tables have turned! (Of course, we have the advantage of building our models on the infallible Word of God!)

Let’s Start Our Thinking on the Word of God

The rapid decay of the earth’s magnetic field is exactly what we should expect when we start our thinking with the Bible’s historical record, as described in Genesis. Genesis 1:1 declares, “In the beginning, God created the heavens and the earth.” And Genesis 1:2 reveals that the earth was covered by water from the beginning, meaning that the initial intensity of the magnetic field could not have been too strong (otherwise it would’ve made the earth too hot to be covered by water). Again, when we base our thinking on the Word of God, the evidence makes sense.

So when we consider the earth’s magnetic field along with the fields of other planets and moons, the only real explanation that fits the data is that these magnetic fields (and thus the heavenly bodies themselves) are not billions of years old but were created just thousands of years ago. This decay rate fits perfectly within a biblical timeframe and stands as another powerful confirmation of the truth and authority of God’s Word.

Open to Rescue?

Now, circling back to our discussion on worldviews, what happens when all this is presented to secular scientists who, based on their worldview, believe the earth and solar system is billions of years old? (Maybe you?) They invent what’s called a “rescuing device”—an attempt to save their worldview in spite of contradictory evidence.25 In this case, they try to explain away the evidence by invoking complex “dynamo models” that assume a self-sustaining field regeneration. In other words, their attempt to explain the field’s persistence over billions of years is through unverified dynamo effects.

However, not only do these “models” rely on unrealistic conditions that contradict basic laws of physics, but they lack any sort of observational support. Instead of accepting the simpler explanation—based on actual measured decay rates that point to a much younger age—they outright reject it. Why? Not because of the science, but because of a religious commitment to naturalism. Ultimately, this should serve as a reminder that the belief in “billions of years” is not really science at all (in fact, it’s anti-science!) but rather a fervent precommitment through which they interpret all evidence.

Secular scientists are very intelligent and knowledgeable. But the issue isn’t intellect—it’s worldview.

Now don’t get me wrong. Secular scientists are very intelligent and knowledgeable. But the issue isn’t intellect—it’s worldview. Or more specifically, here’s the reality: It’s not a head issue—it’s really a heart issue. The Bible makes it clear that because of the sinful heart of man, people would believe anything rather than accept the truth. They suppress what they know to be true and exchange the truth of God for a lie—because they love darkness rather than light (Jeremiah 17:9–10; Romans 1:18–25; John 3:19–21). That’s why the evidence won’t matter to those in rebellion against their Creator—no amount of data can overcome a heart that’s in rebellion against God. Period.

Let’s remember what every person (secularist or not) needs most—not more evidence, but a new heart that loves God, his Word, and his creation that brings glory to him. A change of heart can only happen through the proclamation of the good news. The power of the gospel can transform hearts through the regenerating work of the Holy Spirit. Most importantly, this should serve as a reminder to us Christians to keep faithfully sharing the gospel of Jesus Christ with the world, including those in every field of science today (Mark 16:15).