Unique ‘inside out’ planetary system reveals rocky outer world

A global team of astronomers, led by the University of Warwick, have used a European Space Agency (ESA) telescope to discover a planetary system that turns our understanding of planet formation upside down, with a distant rocky world. In our solar system, the inner planets (Mercury to Mars) are rocky, and the outer planets (Jupiter to Neptune) are gaseous. This planetary pattern—rock then gas—is consistently observed across the Milky Way. That was, until an international team of scientists, led by Dr. Thomas Wilson from the University of Warwick, took a closer look at a star called LHS 1903. Their observations, published in Science, reveal a system of four planets that breaks this convention.