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From NPR.

Jocelyn Bell-Bernille knows that, in space, just as in life, nothing lasts forever.

Bigger stars are at the end of their life, explode dramatically.

They hugely brighten up, they kick out a whole lot of gas and stuff into space.

And the core gets kicked against, gets compressed, gets shrunk right down.

Massive stars more than 20 times bigger than our sun eventually collapse into black holes.

Infinitely small points of immense mass that we can't directly see.

Then, there are smaller stars, still bigger than our sun, that don't fully collapse into black holes.

They're known as neutron stars, because they're largely composed of one of the fundamental

particles that we call neutrons.

Those neutrons, they were created when the pressure from the explosion compressed the protons

and electrons so tightly together they combined.

And so the core of the star becomes a ball that's about 10 miles across typically and

spinning very rapidly, a bit like the ice gauge of pulling our arms in, spins faster.

A chunk of a neutron star, the size of just a sugar cube, would weigh a billion tons

on Earth, or no big deal about the weight of a mountain.

And because of that compression, these stars have much stronger magnetic fields.

The strong magnetic fields keeps the charge particles constrained.

And having lots of energetic charge particles confined to a small volume and whizzing

around like fury will likely give you radio waves.

Which is a good thing, because…

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