Alteration of the magnetosphere of the Vela pulsar during a glitch.

As pulsars lose energy, primarily in the form of magnetic dipole radiation, their rotation slows down accordingly. For some pulsars, this spin-down is interrupted by occasional abrupt spin-up events known as glitches . A glitch is hypothesized to be a catastrophic release of pinned vorticity that provides an exchange of angular momentum between the superfluid outer core and the crust.

Practical limitations on astrophysical observations of methanol to investigate variations in the proton-to-electron mass ratio.

The possibility of using astrophysical observations of rotational transitions in the methanol molecule to measure, or constrain temporal and spatial variations in the proton-to-electron mass ratio (μ) has recently been investigated by several groups. Here we outline some of the practical considerations of making such observations, including both the instrumental and astrophysical limitations which exist at present. This leads us to conclude that such observations are unlikely to be able to improve evidence either for, or against the presence of variations in the proton-to-electron mass ratio by more than an order of magnitude beyond current limits.