Viking Mythology

The eclipses of the moon enabled the ancient Babylonians to predict lunar eclipses fairly accurately.

Eclipses of the sun were more difficult to predict because they are visible only in a corridor on the earth about 30 miles wide.

Thales first predicted a solar eclipse in 585 BC. The great precision of his prediction was probably a lucky guess. He was a shadowy figure who left behind no writings of his own.

His home was one of the intellectual centers in a region called Ionia, which was colonized by the Greeks and exerted an influence that eventually reached from Turkey as far west as Italy.

But over the centuries much of Ionian science would be forgotten—only to be rediscovered or reinvented, sometimes more than once.

According to legend, the first mathematical formulation of a law of nature dates back to an Ionian named Pythagoras (ca. 580 BC–ca. 490 BC).

He discovered the numerical relationship between the length of the strings used in musical instruments and the harmonic combinations of the sounds.

In today’s language, we would describe that relationship by saying that the frequency—the number of vibrations per second—of a string vibrating under fixed tension is inversely proportional to the length of the string.

This explains why bass guitars must have longer strings than ordinary guitars.

Apart from the Pythagorean law of strings, the only physical laws known correctly to the ancients were 3 laws detailed by Archimedes (ca. 287 BC–ca. 212 BC), by far the most eminent physicist of antiquity.*

1. The law of the lever explains that small forces can lift large weights because the lever amplifies a force according to the ratio of the distances from the lever’s fulcrum.

2. The law of buoyancy states that any object immersed in a fluid will experience an upward force equal to the weight of the displaced fluid.

3. The law of reflection asserts that the angle between a beam of light and a mirror is equal to the angle between the mirror and the reflected beam.

But Archimedes did not call them laws. Nor did he explain them with reference to observation and measurement.

Instead, he treated them as if they were purely mathematical theorems, in an axiomatic system much like the one Euclid created for geometry.

As the Ionian influence spread, there appeared others who saw that the universe possesses an internal order, one that could be understood through observation and reason.

Anaximander (ca. 610 BC–ca. 546 BC) was a friend and possibly a student of Thales. He argued that since human infants are helpless at birth, if the first human had somehow appeared on earth as an infant, it would not have survived.

In what may have been humanity’s first inkling of evolution, people, Anaximander reasoned, must therefore have evolved from other animals whose young are hardier.

In Sicily, Empedocles (ca. 490 BC–ca. 430 BC) observed the use of an instrument called a clepsydra.

Sometimes used as a ladle, it consisted of a sphere with an open neck and small holes in its bottom. When immersed in water it would fill, and if the open neck was then covered, the clepsydra could be lifted out without the water in it falling through the holes.

Empedocles noticed that if you cover the neck before you immerse it, a clepsydra does not fill. He reasoned that something invisible must be preventing the water from entering the sphere through the holes—he had discovered the material substance we call air.

Around the same time, Democritus (ca 460 BC–ca. 370 BC), from an Ionian colony in northern Greece, pondered what happened when you break or cut an object into pieces.

He argued that you should not be able to continue the process indefinitely.

Instead, he postulated that everything, including all living beings, is made of fundamental particles that cannot be cut or broken into parts. He named these ultimate particles atoms, from the Greek adjective meaning “uncuttable.”

Democritus believed that every material phenomenon is a product of the collision of atoms.

• His view is called “atomism”
• It says that all atoms move around in space and move forward indefinitely unless disturbed.

Today, that idea is called the law of inertia.