Where would the observation of a static Universe have lead us?

[Tokage]

Had our observations shown shown that the Universe was not expanding, and was instead static, where would that have lead us as far as Cosmology is concerned?

[chrisbaird]

As there is ample evidence of the universe's expansion and evolution in ancient times, an observation that the universe is currently not expanding, but is static would mean that it's expansion has slowed down to a stop recently. This would imply that there is enough matter in the universe to halt expansion under its own gravitational attraction, and there was no other significant factor (like dark energy) causing the expansion beyond the initial big band and inertia.

[Tokage]

As there is ample evidence of the universe's expansion and evolution in ancient times, an observation that the universe is currently not expanding, but is static would mean that it's expansion has slowed down to a stop recently. This would imply that there is enough matter in the universe to halt expansion under its own gravitational attraction, and there was no other significant factor (like dark energy) causing the expansion beyond the initial big band and inertia.

Thanks for the answer chris! What if there had never been any evidence, even in ancient times, that the Universe was expanding?

[Ken G]

Before there was a Big Bang model, there were static universe models. Newton had one after his discovery of the force of gravity, and even Einstein made one after finding general relativity. So the expansion was a recent surprise. Ironically, both Newton's and Einstein's models were wrong-- they would not have been dynamically stable (any perturbation would have made the universe go dynamical, and expand someplaces and contract in others). Also, static universe models always have the problem of needing to figure out what to do with all the detritus that stars make, and no known process could reverse that.

[Hlafordlaes]

Mr. Ken G himself! Here I was bemoaning leaving, um, the other place, and missing out on your threads. I've been mulling over a future post I'd like to make relating to an early paper by Bernard d'Espagnat (meebe Sunday.) Here's hoping you'll be around for that!

Anything similar to your recent classic-quantum perspective-tweaker on this board? I loved that!

(Don't worry, I'll mostly popcorn through your threads from the sidelines as always, even if I won't be able to resist a dumb comment or question on the odd occasion.)