Shifting Pictures of the Universe

A. Traditional

Below is an example of one kind of the many kinds of traditional representations of the universe and of time: the snake swallowing its tail. It is a symbol that one finds all over the world.

A. Traditional Uroboros (snake swalllowing its tail)

B. Biblical

This is a representation of the cosmos of the ancient Near East, the Genesis cosmos. It is a three part picture: the heavens, the flat earth, the underworld. As it is described in Genesis, God separated the waters, providing a space. The firmament held up the upper waters, making space for dry land where animals, plants, and people could find a home. But the firmament had the possibility of breaking, and in the Noah story, the “chimneys” in the firmament and the “fountains” of the deep open up. The Flood was understood as not just a rainstorm but a cosmic catastrophe, a threat to recreate the primordial chaos.

B. Biblical

C. Medieval

The Medieval picture is based on the Ptolemaic and even earlier Platonic and Aristotelian conceptions of the crystalline spheres, with the spherical earth at the center and the whole pattern of spheres revolving around the earth every day. The spheres also revolve slowly against each other. The innermost sphere carries the moon, and then Mercury and Venus and the sun (with Mercury and Venus closely linked to the sun). Beyond the sun were Mars, Jupiter, and Saturn (the Seventh Heaven), the fixed stars, and then angels. This basic picture was reflected in many ways in Medieval culture. For example in a mystical Jewish Kabbalistic representation, there are also the ten spheres, but the story is different. In Lurianic Kabbalah God creates the universe by withdrawing from the center, a process called Tzimtzum in Hebrew. The ten spheres - or spherot, the numbers - represent the emanations of God back into the universe. Ein Sof - the infinite God - surrounds all.

C. Medieval

D. Newtonian

Galileo’s observations with the telescope provided the first convincing evidence that the Ptolemaic picture was wrong. This pulled the rug out from the entire Medieval conception of a hierarchical structure of the universe - including the human universe. Galileo’s work, published in Italy in 1610, spread quickly throughout Europe. Already in 1611 in England John Donne writes: 

The new Philosophy calls all in doubt,
The Element of fire is quite put out;
[the sphere of fire, the highest of the spheres below the lunar sphere, does not exist]
The Sun is lost, and th’earth, and no man’s wit
Can well direct him where to look for it...
‘Tis all in pieces, all coherence gone;
All just supply, and all Relation;
Prince, Subject, Father, Son, are things forgot...

Such was the impact of this change in cosmology.

What was the new picture? The Newtonian cosmos replaced the Medieval picture. There is simply empty space, the void, stretching on indefinitely in all directions. In the Middle Ages, when one went out at night and looked up, one saw majestic height, not infinite vastness. The statement in Pascal’s Pensees, “the eternal silence of these infinite spaces alarms me,”is a sort of statement that one simply never encounters in Medieval writings. But it is a very common view once one is living in the Newtonian universe - here represented by a work by Escher.

D. Newtonian
M.C. Escher's "Cubic Space Division" © 2002 Cordon Art B.V. - Baarn - Holland. All rights reserved.

E. Modern?

Our modern conception bears some elements of all these pictures, but it is very different from all of them. Let me start by summarizing the differences between the Medieval, Newtonian, and modern pictures.

The Medieval cosmos is of finite size, it began a finite length of time ago - which could be calculated by adding up the begats in Genesis - and it was geocentric. The physical part had to be finite in size because the whole thing goes around once every day. There’s a distinction between the material contents of the sublunar world and of the perfect, unchanging heavens. The unifying ideas are constant circular motion and the Great Chain of Being:hierarchy, continuity, plenitude. God pervades the entire structure - or gods: pagan planetology coexisted with Christian cosmology.

Newton argued that if the cosmos were finite, then everything would fall to the center,so it was probably infinite. But there were paradoxes associated with this: Kepler had already pointed out that the night sky would be bright as day in an everlasting infinite universe (“Olber’s paradox”). It also was not clear whether the Newtonian universe was created a finite length of time ago. The unifying ideas were deterministic local mechanics and universal gravitation: the laws of motion were the same on Earth as throughout the universe. God’s role was the creator of this clockwork universe at the beginning. For Newton at least, God also kept setting the clock right again every so often.

In the modern cosmos, we know how big the visible universe is, about 10²⁸ centimeters (cm) - that distance is called the “cosmic horizon.” We know how long ago the universe started - about 14 billion years ago. We know that on large scales, It is homogeneous and isotropic (the same in all directions). It is made of atoms, dark matter, and radiation. Gravity is curvature of spacetime and can create horizons, and nondeterministic quantum mechanics and evolution are the key ideas. It is not clear whether there is a role for God.

Contributed by: Joel Primack and Nancy Abrams