Rocky, the Space Snowman
By Science Insider. Excerpt: Out past Neptune, connected spheres of rock orbit through the solar system like faceless galactic snowmen. Called contact binaries, these objects represent roughly 10% of all planetary building blocks. But how these cosmic curiosities form has remained unclear. Typically, simulations of two colliding space objects model the masses as fluid blobs that squish into a single sphere on impact. But using high-performance computers, ...new models were able to predict the snowman-shaped contact binaries for the first time , scientists reported this week. As for the origins of the binaries, scientists think they began as single objects formed when gravity pulled together dust, gas, and pebbles in the disc of the early Milky Way. As the disc rotated, it ripped apart such objects into two separate chunks that orbited each other. Over time, gravity gently tugged these chunks back together until they fused into their characteristic two-lobed shape.... F...