A neutron star is one of the densest collections of matter in the Universe, but there is an upper limit to their mass. Exceed it, and the neutron star will further collapse to form a black hole. Image credit: ESO / Luis Calcada.

Ask Ethan: How Does Spinning Affect The Shape Of Pulsars?

They’re the fastest rotators of all. So how distorted are they?

There are very few objects in the Universe that stand still; almost everything we know of rotates in some way. Every moon, planet, and star we know of spins on its own axis, meaning that there’s no such thing as a truly perfect sphere in our physical reality. As an object in hydrostatic equilibrium spins, it bulges at the equator while compressing at the poles. Our own Earth is an additional 26 miles (42 km) longer along its equatorial axis than its polar axis due to its once-a-day spin, and there are many things that spin more quickly. What about the objects that spin the fastest? That’s what our Patreon supporter Jason McCampbell wants to know:

[S]ome pulsars have incredible spin rates. How much does this distort the object, and does it shed material this way or is gravity still able to bind all of the material to the object?

There’s a limit to how quickly anything can spin, and while pulsars are no exception, some of them are truly exceptional.

The Vela pulsar, like all pulsars, is an example of a neutron star corpse. The gas and matter surrounding it is quite common, and is capable of providing fuel for the pulsing behavior of these neutron stars. Image credit: NASA/CXC/PSU/G.Pavlov et al.