Pulsars spin exceptionally rapidly, up to hundreds of times per second. How is this possible when most objects in space rotate at around the same rate as the Earth? This is largely due to a concept called conservation of angular momentum.

Pulsars have about the same mass as our sun, but are incredibly smaller, and thus rotate much quicker.

At the end of some stars' lives, they will collapse to their centre. While this is happening, they are still rotating. The result of the object's rotation and compression, the particles that make the star up gain speed as they are being pulled to the centre. The product of this is a small, dense sphere that rotates extremely fast.

This phenomenon can be described mathematically, by saying that angular momentum is a product of an objects mass, the magnitude of its velocity (the speed at which it is rotating), and its radius (the distance between the centre of the object and the particles that are moving towards the centre). This is shown in the formula L=vmr. See the diagram below for further explanation.

Figure skaters use conservation of angular momentum to their advantage as well. When they are rotating with their arms out, they pull their arms in, picking up rotational speed as they do this. This animation of a figure skater may help you further understand angular momentum.