  Recent developments in gravitation theory indicate that the classic general
relativity is an effective macroscopic theory which will be eventually replaced
with a more fundamental theory based on thermodynamics of yet unknown
microscopic degrees of freedom. Here we consider thermodynamics of an effective
Minkowski spacetime which may be formed under the influence of external
magnetic field in a cobalt ferrofluid. It appears that the extraordinary
photons propagating inside the ferrofluid perceive thermal gradients in the
ferrofluid as an effective gravitational field, which obeys the Newton law.
Moreover, the effective Minkowski spacetime behaviour near the metric signature
transition may mimic various cosmological Big Bang scenarios, which may be
visualized directly using an optical microscope. Thus, some important features
of the hypothetic microscopic theory of gravity are reproduced in the
ferrofluid-based analogue model.
