Planck-scale structure of spacetime and some implications for astrophysics and cosmology

TL;DR

This paper reviews various theoretical models of Planck-scale spacetime structure, discussing their differences and potential implications for astrophysics and cosmology.

Contribution

It compares different quantum gravity schemes involving maximum acceleration and minimum wavelength, highlighting their possible astrophysical and cosmological impacts.

Findings

Different quantum gravity models predict distinct Planck-scale spacetime features.

Some models imply observable effects in astrophysics and cosmology.

The structure of spacetime at the Planck scale may involve discretization or noncommutativity.

Abstract

I briefly review some scenarios for the role of the Planck length in quantum gravity. In particular, I examine the differences between the schemes in which quantum gravity is expected to introduce a maximum acceleration and the schemes in which the Planck length sets the minimum value of wavelengths (maximum value of momentum). I also comment on some pictures for the structure of spacetime at the Planck scale, such as spacetime discretization and spacetime noncommutativity. I stress that some of these proposals can have significant implications in astrophysics and cosmology.