In 1929, Edwin Hubble used his famous telescope to determine that galaxies were not fixed, as scientists had thought. All of them – including ours – were moving away from one another.
He thought about this for a long time. Logic dictated that if galaxies were always moving away from one another, they must have been closer together in the past. At the beginning of the universe, he reasoned, they might have been one solid ball.
How far had the universe expanded since then? In 1967, two radio engineers working for Bell Laboratories noticed a hissing noise in their instruments. They theorized that it could be sound waves from photons at the outer edge of the universe – 90 billion trillion miles away. Subsequent studies confirmed their hypothesis.
Six decades later, scientists came to the conclusion that the universe originated 13.7 billion years ago as the result of some sort of cataclysmic event: a “big bang.” The idea was that all energy was once concentrated… and it suddenly exploded to form atoms, elements, and, ultimately, galaxies.
It is difficult to find any scientist today who disagrees with this theory. Virtually everyone with serious credentials agrees that the universe was (a) once a contracted core of energy and (b) is now steadily expanding outwards.
These are really two separate statements. The first one is a theory based on logic; the second one is an observation that has been confirmed by scientific experiment. Interestingly, both are fundamental to quantum physics and everything that we have learned from quantum physics.
And they give us our first clue about the relationship between expansion and contraction.