Neutron Star

When stars evolve off the main sequence, the physics of gravity overpowers whatever nuclear exhaust is left, and stars of all sizes ultimately collapse into exotic physical forms. The middle children of the stellar population, those to large to become white dwarfs and too small to rip the fabric of spacetime apart and become black holes, become neutron stars. You can read more about these end-stage stars here:
Neutron star

I don't mean to sound like a hipster, but this is more mainstream than most of the topics I write about in this space. Why talk about something we read about in a high school science textbook? While I assume that most people with a background in science have some passing understanding of what neutron stars are, the details are more esoteric, and were new to me until I wound up derping around on the Wikipedia page earlier today. It's interesting to see how strange life becomes when gravity's volume is turned up to 11.

Gravity is by far the weakest of the fundamental forces of physical law. The nuclear forces bind protons and neutrons together in a vice grip that can't be broken until temperatures in the millions of degrees, and a few ounces of steel can easily defeat all the Earth's gravity in a tug-of-war when a magnet sticks to the fridge. In all the places people go gravity's call is pound for pound nothing but a whisper. Inside a neutron star, though, where the mass of half a million Earths is compressed into the size of a thunderhead, the tug is enough to slow the passage of time and create a layer cake of wonderland flavors of matter.

Not convinced that the inside of a neutron star is an exotically exciting place? Consider for a moment that the best diagram we can draw of such a place, based on the combined observations and theoretical development of a century in astronomy, particle physics, and relativity, has a question mark right in the bull's-eye: