Sub-Neptune exoplanets tend to be much closer to their host star than Earth is to the Sun and are thought to have atmospheres made of steam over layers of an exotic phase of water that behaves like ...

In 2009, a pair of astronomers at the Paris Observatory announced a startling discovery. After building a detailed computational model of our solar system, they ran thousands of numerical simulations, ...

Animation of a steam world’s evolution from formation to very old age (100 million years to 20 billion years). The interior is initially hot, and cools over time. How fast the planet cools is ...