As though there wasn't already enough cool stuff in the cosmos, scientists say space may hold enormous, spinning space donuts made of blistering-hot vaporized rock. They published their report in the Journal of Geophysical Research: Planets.
Planetary scientists Simon Lock and Sarah Stewart were trying to understand what happens when two planets collide. As we know from our own Earth, planets are not simply dead rocks or balls of gas, but active, complex bodies, with constantly shifting temperatures, orbits, shape, rotation, and gravity.
Consequently, planet-on-planet wrecks are less like a smashing of rocks and more like a figure-skating accident, a sudden, midair arresting of whirling triple axels.
The impact of these crashes is so violent, astronomers believe, that the two bodies involved are reduced to hot rubble. Over time, that rubble cools and congeals, eventually spinning and condensing into a new celestial body. It was this kind of smash-up, some scientists say, that created the Earth.
Lock and Stewart aren’t so sure about that. They think our planet’s origins may have been bigger, and substantially more donut-shaped. They hypothesize that the heat and momentum of these collisions can fling hot debris into a big, fat rotating ring they call a synestia.
From there, the process is similar: The vaporized rock cools and begins to stick together, coalescing into a rocky baby planet—and possibly a moon or two.
After centuries of study, we’re still not totally sure how our own Moon was born. Much of its composition is similar to Earth’s, which suggests, Lock and Stewart say, that the cosmic donut could have birthed them both.
The term synestia is their invention, too, a blend of the prefix syn, meaning “together,” and Hestia, the Greek goddess of home, the hearth, and architecture.
A real synestia has yet to be spotted in space, but the scientists are confident that they’ll turn up once we dig deeper into other solar systems.