The Magnetic Field of the Earth

[The Magnetic Field of the Earth by Dr. Jason Lisle] "Most people have some familiarity with magnets, like the kind that stick to a refrigerator door. Magnets have an almost “magical” ability to attract other magnets or certain metals separated by a distance—they seem to reach out over space and pull with invisible fingers. The region of space surrounding a magnet which exerts a force on other magnets is called a “magnetic field.” Magnetic fields are caused by electric current—motion of charged particles.

The earth’s magnetic field is approximated by a “dipole”—meaning the magnet has one north pole and one south pole. This dipole is roughly aligned with the earth’s rotation axis (being off by about 11.5 degrees). That is, the north magnetic pole is close to the north rotation pole. This is why a compass points approximately north; it aligns with the geomagnetic field. This magnetic field surrounds the earth and is an important design feature. The universe contains radiation which is harmful to living tissue. Earth’s magnetic field protects life by deflecting dangerous cosmic radiation. The atmosphere also offers some protection.

The earth’s magnetic field is caused by electric currents within its interior. Such currents encounter electrical resistance, and so they naturally decay with time. We would therefore expect that earth’s magnetic field would become weaker as time progresses. We have been able to measure the strength of the magnetic field for over a century, and not surprisingly, the earth’s magnetic field is indeed decaying. Every century, the magnetic field decays by about 5 percent. Since the earth’s magnetic field gets weaker as time moves forward, it must have been considerably stronger in the past. Approximately 6,000 years ago, the magnetic field would have been quite a lot stronger, but still perfectly suitable for life.

However, if the earth were many millions of years old, then the geomagnetic field would have been so strong in that alleged distant past, that life would not have been possible."  The Magnetic Field of the Earth, Lisle. http://www.answersingenesis.org/articles/tba/age-of-the-universe-2

The Magnetic Field of the Earth