Neutron star matter weighs about the same as an ordinary mountain per teaspoonful – so much that if you had a piece of neutron star and let it go (hum… you could hardly do otherwise), it might pass effortlessly through the Earth like a falling stone through air, carving a hole for itself completely through our planet and emerging out the other side – perhaps in China.
If a peace of neutron star matter were dropped from nearby space, with the Earth rotating beneath it as it fell, it would plunge repeatedly through, punching hundreds of thousands of holes before friction with the interior of our planet stopped the motion.
Let’s imagine: people there might be out for a stroll, minding their own business, when a tiny lump of neutron star plummets out of the ground, hovers for a moment, and then returns beneath the Earth, providing at least a diversion from the routine of the day.
Before it comes to rest at the center of the Earth, the inside of our planet might look briefly like a Swiss cheese until the subterranean flow of rock and metal healed the wounds.
Large lumps of neutron star matter are unknown on Earth. But small lumps are everywhere. The awesome power of the neutron star is lurking in the nucleus of every atom, hidden in every teacup and dormouse, every breath of air, every apple pie. The neutron star teaches us respect for the commonplace.
A star like the Sun will end its days, as we know, as a red giant and then a white dwarf. A collapsing star twice as massive as the Sun will become a supernova and then a neutron star. But a massive star, left, after its supernova phase, with, say, five times the Sun’s mass, has an even more remarkable fate reserved for it – its gravity will turn it into a black hole.
Thermonuclear reactions in the solar interior support the outer layers of the Sun and postpone for billions of years a catastrophic gravitational collapse.
For white dwarfs, the pressure of the electrons, stripped from their nuclei, holds the star up. For neutron stars, the pressure of the neutrons staves off gravity. But for an elderly star left after supernova explosions and other impetuosities with more than several times the Sun’s mass, there are no forces known that can prevent collapse.
The star shrinks incredibly, spins, reddens and disappears. A massive star will shrink until it is the size of a city, the crushing gravity acts irrevocably, and the star slips through a self-generated crack in the space-time continuum and vanishes from our universe.
What if every neutron star is an intelligent being? Image : © Megan Jorgensen