Neutron stars are ancient remnants of stars that have reached the end of their evolutionary journey through space and time.
“Astronomy compels the soul to look upwards and leads us from this world to another.” – Plato
Artist’s illustration of an isolated neutron star
These interesting objects are born from once-large stars that grew to four to eight times the size of our own sun before exploding in catastrophic supernovae.
After such an explosion blows a star’s outer layers into space, the core remains—but it no longer produces nuclear fusion.
With no outward pressure from fusion to counterbalance gravity’s inward pull, the star condenses and collapses in upon itself.
Despite their small diameters—about 12.5 miles (20 kilometres)—neutron stars boast nearly 1.5 times the mass of our sun, and are thus incredibly dense. Just a sugar cube of neutron star matter would weigh about one hundred million tons on Earth.
A neutron star’s almost incomprehensible density causes protons and electrons to combine into neutrons—the process that gives such stars their name. The composition of their cores is unknown, but they may consist of a neutron superfluid or some unknown state of matter.
Neutron stars pack an extremely strong gravitational pull, much greater than Earth’s. This gravitational strength is particularly impressive because of the stars’ small size.
“Recognize that the very molecules that make up your body, the atoms that construct the molecules, are traceable to the crucibles that were once the centres of high mass stars that exploded their chemically rich guts into the galaxy, enriching pristine gas clouds with the chemistry of life. So that we are all connected to each other biologically, to the earth chemically and to the rest of the universe atomically. That’s kinda cool! That makes me smile and I actually feel quite large at the end of that. It’s not that we are better than the universe, we are part of the universe. We are in the universe and the universe is in us.” – Neil deGrasse Tyson
When they are formed, neutron stars rotate in space. As they compress and shrink, this spinning speeds up because of the conservation of angular momentum—the same principle that causes a spinning skater to speed up when she pulls in her arms.