In this 2004 map of magnetic declination, the agonic line (in black) passes through the Midwest and the Gulf of Mexico.

Image courtesy National Geophysical Data Center

Compass Malfunctions

In almost every account of the mystery surrounding the Bermuda Triangle, you'll see reference to the fact that it is one of only two places on Earth (the other being the Devil's Sea off the coast of Japan) where a compass points to true north rather than magnetic north. Theorists say that this causes compasses to malfunction and ships and planes to get off-course.

A compass works because its magnetic needle is attracted by the magnetism of the Earth, which draws it to point to the constantly shifting Magnetic North Pole. The Geographic North Pole, on the other hand, is static and is located about 1200 miles north of the Magnetic Pole. The variation between the two readings is known as magnetic declination (or compass variation), which can change by as much as 20 degrees as you move across the globe.

The agonic line is an imaginary line where true north and magnetic north are in perfect alignment - there is no magnetic declination. At points west of the agonic line, a magnetic needle will point east of true north (positive declination). At points east of the agonic line, a magnetic needle will point west of true north (negative declination). Extended lines that mark the constant magnetic declination away from the agonic line are called isogonic lines.

In the early 18th century, Edmund Halley noticed that the agonic line was slowly moving westward. Since then, scientists have noted a westward drift of the agonic line with an average velocity of about 0.2 degrees per year. The drift is not equal in all places, however. It is stronger in the Atlantic Hemisphere than in the Pacific Hemisphere. Navigators must always compensate for magnetic declination when charting their courses.

While the agonic line once passed through the Bermuda Triangle, it now falls within the Gulf of Mexico, rendering claims that it can contribute to disappearances in the Triangle inaccurate. Calculation errors anywhere could cause a plane or ship to go off-course. This theory also assumes that experienced pilots and captains passing through the area were unaware of magnetic declination, which is unlikely.

One of many blue holes around the Bahamas

Image courtesy Aqua Cat Cruises/ Rick Frehsee

Blue Holes

Blue holes are water-filled caves and cavities with blue coloration. These caves may be simply a hole in the ground in the interior of islands (inland blue holes) or holes in shallow waters on the banks (marine or ocean blue holes). British scuba diver Rob Palmer directed a blue holes research center in the Bahamas for a number of years. In July 1997, he failed to surface after a dive in the Red Sea and was presumed dead. Some think that the blue holes may be related to (or even formed by) micro-wormholes believed to exist in the area and might even be transit points for UFOs arriving here from other dimensions.

Next, we'll look at a few plausible theories for disappearances within the Bermuda Triangle.