"New" 1931 Einstein mss: one math boo-boo away from expanding universe?

[Leo_Bloom]

Here’s an article on an obscure Einstein manuscript recently re-discovered. It makes it sound like Einstein made his decisions pretty damn quick, which I can’t believe, or that’s one mean mother of an equation (or two) upon which A Lot rested.

That’s a question I quickly had, but of course am interested in Einstein’s approach to the subject in general. I know there’s an active bunch of friendly physicists aboard. Or abroad. Or about. :: neat how each word is acceptable… ::

[Chronos]

One can get such a model out of general relativity, and it used to be a somewhat popular model. Checking Wikipedia, though, it looks like it was first proposed in the 1920s, so Einstein probably didn’t have anything new in 1931.

[Leo_Bloom]

So what was he on about, as the Brits say?

[lisiate]

Here’s a link to the full paper.

Some key quotes.

We note first that there is no mention of steady-state solutions in Einstein’s later
discussions of cosmic models (Einstein 1931b, Einstein and de Sitter 1932, Einstein 1945),
nor have we been able to find a reference to the manuscript under discussion in Einstein’s
letters, diaries or other personal papers. This silence indicates that he decided against the
model, rather than simply mislaid the manuscript during his travels or neglected to publish it.

We suggest that the model was discarded because it contains a fundamental flaw.
…
In the manuscript, Einstein explores a steady-state universe of expanding radius, non-zero cosmological constant and constant matter density, where the latter is maintained by the continuous formation of matter from empty space; this model anticipates the well-known ‘steady-state’ cosmologies of the late 1940s and 1950s.
…
The manuscript was almost certainly written after 1929 and very likely before
Einstein’s published cosmic models of 1931 and 1932. The manuscript was probably discarded due to a fundamental flaw in the specific model proposed, and we suggest that Einstein declined to try again because he came to the view that steady-state models of the cosmos were rather contrived and not realistic. The manuscript is nevertheless of great interest in the study of 20th century cosmology because it suggests that Einstein debated
between steady-state and evolving models of the universe decades before a similar debate
took place in the wider cosmological community.

[Asympotically_fat]

@Leo_Bloom

Here’s an article on an obscure Einstein manuscript recently re-discovered. It makes it sound like Einstein made his decisions pretty damn quick, which I can’t believe, or that’s one mean mother of an equation (or two) upon which A Lot rested.

That’s a question I quickly had, but of course am interested in Einstein’s approach to the subject in general. I know there’s an active bunch of friendly physicists aboard. Or abroad. Or about. :: neat how each word is acceptable… ::

Einstein would’ve been well aware of expanding cosmology when he wrote that. The equations he wrote are based on the Friedman equations describing an expanding Universe from 1922.

It’s difficult to know without context, but he probably wrote an equation for the dynamics of the Universe which achieved the steady state he was looking for, but quickly saw that it violated general relativity and moved on. In some ways not that interesting.