magnetic

What are neutron stars and pulsars?

by

A neutron star is what remains when a massive star’s core collapses in a supernova. It packs more mass than the Sun into a sphere only about 20 kilometers (12 miles) across, roughly the size of a city. How extreme are they? The core is thought to be made mostly of neutrons, though what happens … Read more

How do astronomers study the magnetic fields of planets?

by

A planet’s magnetic field is invisible, but it reveals what is happening deep inside and protects the planet from the solar wind. Astronomers study these fields mostly with spacecraft, and also through auroras and radio waves. Where do planetary magnetic fields come from? Most come from a dynamo: a flowing, electrically conducting fluid inside a … Read more