An international team of astronomers has discovered a distant planetary system that challenges long-standing theories of how planets form. Across our galaxy, astronomers routinely observe a characteristic pattern in planetary systems: rocky planets orbiting close to their host star with gas giants farther away. Our own solar system follows this rule, with the inner planets: Mercury, Venus, Earth and Mars, composed of rock and iron, and the outer planets: Jupiter, Saturn, Uranus and Neptune being predominantly gaseous.
This pattern stems from a well-established theory of planet formation: intense radiation from the host star strips away gas accumulated by close-in planets, leaving behind bare rocky bodies. While further from the star, cooler conditions allow thick atmospheres to build, forming gaseous planets.
But a newly discovered planetary system orbiting the star LHS 1903 breaks this rule. The findings are published in Science.