"What if the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed blueberries?”

Abstract

This paper explores the physics of the what-if question “what if the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed blueberries?”. While the assumption may be absurd, the consequences can be explored rigorously using elementary physics. The result is not entirely dissimilar to a small ocean-world exoplanet.

1 Introduction

On the question-and-answer website Physics Stackexchange the user “Billybodega” asked the question1:

Supposing that the entire Earth was instantaneously replaced with an equal volume of closely packed, but uncompressed blueberries, what would happen from the perspective of a person on the surface?

Unfortunately the site tends to frown on fun what-if questions like this, so it was in my opinion prematurely closed while I was working out the answer. So here it is, with some extra extensions and corrections. The following modelling is more qualitative than quantitative, as befits as somewhatloose scenario. Still, it is possible to do a fairly rigorous analysis of what would occur and the properties of the resulting body.

Summary

So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries, the first effect would be a drastic reduction of gravity. Standing on the blueberries might be possible in theory, except that almost immediately they begin to compress rapidly and air starts erupting everywhere. The effect is basically the worst earthquake ever, and it keeps on going until everything has fallen 715 km. While this is going on everything heats up drastically until the entire environment is boiling jam and steam. The end result is a world that has a steam atmosphere covering an ocean of jam on top of warm blueberry granita.
...

There is more (Pdf)