All of the planets that we know and love in our solar system follow a pretty regular life. They spin about an axis, revolve around the central Sun, and go about their business in the small, but vast, family of the solar system.
We are most familiar with “planets” as being what is similar to our solar system. Bodies of rock or gas caught in the pull of a massive star, following an orbit dictated by the laws of gravity.
However, not all planets are like this. It is too easy to get caught in the bias that everything we see on Earth is representative of the universe; the truth is that the universe is a vast, mysterious, and strange place. In addition to the usual planets familiar to us, there exist billions of rogue planets, who live quite different lives to the celestial bodies near us. Instead of orbiting around a central star (or anything at all), they drift aimlessly in space, only the occasional one lucky enough to get caught by a star, becoming “adopted” in sense.
An artist’s perception of a rogue planet
Rogue planets weren’t always rogue, however. Most rogue planets are believed to have been ordinary members of a solar system, until a cataclysmic event resulted in one or several planets being completely knocked out of orbit. Possibilities include a massive collision with the planet, a massive collision with the central star, or even just another large body passing close enough to completely throw off the gravitational balance that makes up the serene solar system.
As if being an orphaned planet wasn’t sad enough, the surface of the planet is most likely equally desolate and miserable as its abandonment. Without a star to provide it light energy, liquid water would freeze into ice quickly, and any hope of civilization on the surface would be gone forever. Interestingly, if a “blanket” of ice forms properly and thickly enough, it could theoretically insulate the ocean of water underneath, similarly to how a bed of snow can actually insulate the grass underneath. There’s not much hope for advanced life on such a planet, but scientists do believe there is a slim chance extremophiles could find a way to adapt to such an environment.