The earth is surrounded by a magnetic field that protects living things from solar radiation. Without it, life could not exist. That’s why scientists were surprised to discover that the field is quickly wearing down. At the current rate, the field and thus the earth could be no older than 20,000 years old.

The earth’s magnetic field is wearing down so quickly that it could be no more than 20,000 years old.

Several measurements confirm this decay. Since measuring began in 1845, the total energy stored in the earth’s magnetic field has been decaying at a rate of 5% per century.¹ Archaeological measurements show that the field was 40% stronger in AD 1000.² Recent records of the International Geomagnetic Reference Field, the most accurate ever taken, show a net energy loss of 1.4% in just three decades (1970–2000).³ This means that the field’s energy has halved every 1,465 years or so.

Creationists have proposed that the earth’s magnetic field is caused by a freely-decaying electric current in the earth’s core. This means that the electric current naturally loses energy, or “decays,” as it flows through the metallic core. Though it differs from the most commonly accepted conventional model, it is consistent with our knowledge of what makes up the earth’s core.⁴ Furthermore, based on what we know about the conductive properties of liquid iron, this freely decaying current would have started when the earth’s outer core was formed. However, if the core were more than 20,000 years old, then the starting energy would have made the earth too hot to be covered by water, as Genesis 1:2 reveals.

Figure 1: Creationists have proposed that the earth’s magnetic field is caused by a freely decaying electric current in the earth’s core. (Old-earth scientists are forced to adopt a theoretical, self-sustaining process known as the dynamo model, which contradicts some basic laws of physics.) Reliable, accurate, published geological field data have emphatically confirmed this young-earth model.

Reliable, accurate, published geological field data have emphatically confirmed the young-earth model: a freely-decaying electric current in the outer core is generating the magnetic field.⁵ Although this field reversed direction several times during the Flood cataclysm when the outer core was stirred (Figure 1), the field has rapidly and continuously lost total energy ever since creation (Figure 2). It all points to an earth and magnetic field only about 6,000 years old.⁶

Figure 2: The earth’s magnetic field has rapidly and continuously lost total energy since its origin, no matter which model has been adopted to explain its magnetism. According to creationists’ dynamic decay model, the earth’s magnetic field lost more energy during the Flood, when the outer core was stirred and the field reversed direction several times.

Rescuing Devices

Old-earth advocates maintain the earth is over 4.5 billion years old, so they believe the magnetic field must be self-sustaining. They propose a complex, theoretical process known as the dynamo model, but such a model contradicts some basic laws of physics. Furthermore, their model fails to explain the modern, measured electric current in the seafloor.⁷ Nor can it explain the past field reversals, computer simulations notwithstanding.⁸

To salvage their old earth and dynamo, some have suggested the magnetic field decay is linear rather than exponential, in spite of the historic measurements and decades of experiments confirming the exponential decay. Others have suggested that the strength of some components increases to make up for other components that are decaying. That claim results from confusion about the difference between magnetic field intensity and its energy, and has been refuted categorically by creation physicists.⁹