Water Worlds May Hide Water Underground

Combining two measurements taken for each of 43 exoplanets, scientists found the densities lower than expected, suggesting the presence of subsurface liquid.

IMAGE: A new study suggests that many more planets in distant solar systems have large amounts of water than previously thought — as much as half water and half rock. The catch? It’s probably imbedded underground, as in Jupiter’s moon Europa, above. CREDIT: NASA/JPL-Caltech/SETI Institute

While Mars is just one other world in our solar system that once had water — and still may have water underground — it’s not the only…