Jupiter is a gigantic ball of churning gas clouds, and that makes it hard to see what’s in the middle. It’s believed to be a relatively small, rocky core, but data from the Juno probe found that it’s less dense and more spread out than expected. Now, astronomers believe they have an answer – a huge ancient planet, with 10 times the mass of Earth, crashed into the gas giant in the early days of the solar system.
Juno has been circling Jupiter for more than three years, conducting a number of flybys and studying the gas giant with various instruments. Along with snapping photos of the clouds with unprecedented clarity, the craft also managed to probe below them, taking gravitational readings to get an idea of the core. And surprisingly, it was found to be less dense and more extended than scientists thought.
But researchers on the new study, involving astronomers from Rice University in the US and Sun Yat-sen University in China, have a new theory to explain it. The team says that a colossal collision in the distant past could have churned up the core, mixing the dense materials in the middle with the gaseous or liquid layers above it. That could have the effect of making it both larger and less dense, as Juno suggested.