Space and time

 Would There Be Time Without Space Expanding?

The concept of time is intimately tied to space in modern physics. Since the early 20th century, scientists have come to understand that time is not an isolated entity ticking along on its own — it is part of a greater fabric known as spacetime, a four-dimensional continuum that merges the three spatial dimensions with time. In this context, an intriguing question arises: Would there be time if space weren’t expanding?

To explore this, we must journey through both physics and philosophy, beginning with our current understanding of the universe.

Spacetime and the Expanding Universe

According to Einstein’s General Theory of Relativity, space and time are interwoven, and massive objects bend this fabric, creating gravity. One of the most profound implications of Einstein’s equations, confirmed by astronomical observations, is that the universe is expanding. Galaxies are moving away from one another, and space itself is stretching over time.

This expansion isn’t just movement through space — it’s the expansion of space itself. Since the Big Bang, about 13.8 billion years ago, the universe has grown from an unimaginably hot, dense point to its current vast size. The passage of time, from our perspective, has always accompanied this expansion.

If Space Didn’t Expand, Would Time Still Exist?

This is where things become speculative. If we imagine a universe where space is static — neither expanding nor contracting — the key question becomes whether such a scenario could physically exist.

In theory, time could still exist in a non-expanding universe. Time is a dimension, just like space, and as long as events occur and change happens, there is a basis for time. In fact, Einstein’s equations allow for static solutions (such as the “Einstein static universe,” which he originally proposed before the discovery of cosmic expansion). However, such models are typically unstable — any small perturbation would either cause the universe to expand or collapse.

But there’s a deeper layer: Would time still “flow” without cosmic change? Many physicists argue that time as we perceive it — with a direction, a “before” and “after” — is closely linked to entropy, the tendency of systems to move from order to disorder. This progression gives rise to the so-called “arrow of time.” If the universe were completely static, with no change in entropy, the concept of time might lose its meaning. No change means no “before” or “after” — time could exist mathematically, but not experientially.

Quantum and Philosophical Considerations

In some approaches to quantum gravity, like loop quantum gravity or the Wheeler-DeWitt equation, time disappears altogether from the fundamental equations. In these views, time is not a fundamental ingredient of the universe but an emergent property — a byproduct of interactions within the universe, particularly those involving observers.

If this is the case, and the expansion of space is part of the dynamic processes that give rise to the flow of time, then perhaps in a non-expanding universe, there would be no time as we know it — not because it couldn’t exist, but because nothing would give it substance.

Conclusion: A Universe Frozen in Stillness?

So, would there be time without space expanding?

From a mathematical standpoint, yes, time could exist in a static universe. But from a physical and experiential standpoint, it becomes more ambiguous. If nothing changes — if entropy remains constant, and no events unfold — then the meaning of time becomes elusive. Time may be written into the equations, but in a truly changeless cosmos, it may be indistinguishable from timelessness.

In the end, time may not need space to expand to exist — but it may need change, motion, and evolution to matter. Without space expanding, we might still have a concept of time — but without the unfolding of the cosmos, it could be a concept without consequence.