A neutron star is a collapsed remnant that remains after a supernova has destroyed a large star. They form if a star is large enough to explode in a supernova, yet small enough not to implode into a black hole. They are just a few kilometres across despite having masses as much as several times our sun. As such, they are extremely dense and have enormously high gravity that would instantly crush anything on the surface. At these densities, matter is crushed into a degenerate form made largely from a sea of neutrons. There are multiple types of neutron star with different properties.
Magnetars are neutron stars with an extremely powerful magnetic field, millions of times stronger than any magnetic field that has been made by artificial means, and thousands of times stronger than other neutron stars. The magnetism can distort the shapes of atoms into cylinders within a thousand kilometres and would be fatal to humans at great distances. Any electronics would suffer even further out.
Pulsars are neutron stars that spray beams of radiation and rotate quickly, seeming to emit regular pulses in any direction as the beam sweeps around. The first planet to be discovered outside our solar system orbited a pulsar, though the high levels of radiation should make them quite hostile places, damaging atmospheres and scouring the surfaces, the ionized matter streaming into a glowing aurora. A glowing, haloed point in the sky would mark the neutron star itself. It is thought that these planets formed from heavy supernova wreckage, but they may have formed earlier and somehow survived before the explosion.
Game and Story Use
- Any life around a neutron star would need to be hidden away within underground oceans, feeding on volcanic emissions and magnetic flux rather than light.
- Think tubular coral reefs on the roof of a watery cavern, harvesting magnetic energy over their lengths.
- Without light, more unusual senses such as echolocation or even microwave vision might be common.
- A few bioluminescent creatures could light up the reefs and hydrothermal vents eerily.
- The magnetic fields might cause hallucinations by messing with the brain.