Picture a lovely river valley, with high alpine peaks on either side. Trees and broken meadows fill in a patchwork of the view. If a view of a landscape stays relatively the same over observable time, people can think of this vista as a “steady state” landscape.
It is the same principle behind the Quasi Steady State view of the Cosmos.
But, much like the steady, seemingly constant landscape, there are actually new trees, and new grasses in the meadows every day. There are trees and plants dying every day, as well. There are bits of dirt and rock eroding off the seemingly solid mountain peaks. And there are new rocks and soils being formed to take the place of those falling off. Even the river has new volumes of water flowing each day. The idea was postulated that like such a place on Earth, the entire cosmos had space, matter and energy, in a flux that is ongoing and only realized to be so dynamic, when examined up close.
The view, then, looks steady, but in fact instances of creation are on-going and only the appearance is one of constancy.
With the cosmos, in the 1940s, the same thinking was applied at a much larger scale. Not being able to account for the heat and composition of the universe as it appeared, scientists George Gamow and Fred Hoyle wondered if, instead of a Big Bang, the universe could be ever-changing, even as it appeared static. That is, it is observable as unchanging, from every perspective, although forever punctuated with the creation of new matter and ever-flowing in expansion.
Ylem is an early word for matter. Gamow and his graduate student, Ralph Alpher, gave this title to their steady state hypothesis, which assumed ongoing creation of matter rather than a singular event of extreme heat and density of elements which cooled and expanded over time. This view of the cosmos could be observable as dynamic, even while it could have existed forever.
The Big Bang theory says that all elements were created in one initial blast, which then began to cool and expand. Hoyle wondered if these elements, primarily, could be formed in past and presently occurring stellar events instead.
In fact, Fred Hoyle is said to have derisively referred to the singular blast, saying such a “Big Bang” could not be the origin of the universe. In their model, the universe has no beginning and no end. It has no primary creation event but is simply evolving, much like a landscape on Earth.
In 1947, Fred Hoyle is said to have attended a movie with fellow scientists Tommy Gold and Herman Bondi. The film was a ghost story that ended in the same way it began. This is said to have prompted conversation among the men regarding how the universe could appear unchanging in observation over time. This gave rise to the Cosmological Principle, which dictates a homogeneous universe, even while creation is on-going within new stellar furnaces. This would explain why the observable universe appears to be unchanging from any different perspective at any given time. It would have no beginning and no end.
The Perfect Cosmological Principle came later, adding another requirement: that such a universe may even have new galaxies formed while continuing the same rate of expansion. This would allow a universe that is emerging, expanding and still observable as steady.
However, by the 1970s new advances in radio astronomy were able to pinpoint sources of radio waves that were unevenly distributed, especially from what could only be “older” fragments in the very distant realms of the known universe.
Martin Ryle of Cambridge examined over 2,000 sources of radio static he surveyed in the early 1950’s. That the sources were found farther and farther away suggested that the steady state theory could not be correct. Ryle was awarded the Nobel prize for his overall contributions to astronomy. The Big Bang theory won out over the Quasi Steady State theory, at least for now.