Reality Need Not Diminish Our Concept of Our Place In the Cosmos

BY STEPHEN B. GRAY

IN THE INTELLECTUAL CHILDHOOD of Homo sapiens, before the appearance of science a few centuries ago, most of the Western world held the egocentric view that we are the center and purpose of the universe, created and cared for by God. As scientific knowledge grew, this notion became obsolete, but many monotheists still think we are uniquely favored.

The initial (and biggest) shocks to this anthropocentric view were heliocentrism and Darwinian evolution. Both had influences far beyond their initial scientific implications, and both were strenuously opposed by religious believers. But those humbling developments were only two of many that upset the traditional picture. Here are a few of the ways that scientific discoveries have put our place in the cosmos into perspective.

Earth’s size: The ancient Greeks proved that the Earth is a sphere of immense size. They also estimated even greater distances, such as the distance to the Moon.1 The realization of our insignificance had begun.

Earth’s Shape: Aristotle (384-322 BCE) found that the Earth is not flat by noting that as one travels north, different parts of the heavens are visible. He also observed that during an eclipse of the Moon, the Earth’s shadow on it is a circular arc.2 The literal biblical view was flatly contradicted.

Larger Distances: Ptolemy (c. 87-150 CE) computed the first truly great size of the cosmos. Using assumptions that we now know to be false, he made a calculation that the universe, which he thought was limited to Earth, Sun, Moon, and five planets, has a radius of about 75 million miles. His measurement was much too small, but it was the first sign that the universe is incomparably larger than the Earth.3

The Universe Does Not Revolve Around Us: During the Scientific Revolution, Copernicus, Kepler, and Galileo demonstrated that the Earth is not the stationary center of the Solar System. Galileo’s 1610 observations of Jupiter’s moons proved that they orbited that planet, hence not all astronomical bodies revolve around the Earth. The new concept that the Earth was not fixed, but orbited around the stationary Sun and stars was a revolutionary step in deflating anthropocentrism. 4