A bright ring of dust circling a young star can look calm from far away. In reality, it may mark one of the messiest moments in planetary birth, where gas, pebbles, and gravity are still fighting over what kind of solar system will emerge. These disks, the swirling bands of gas and dust around young stars, are where planets form. Modern observatories such as the Atacama Large Millimeter/submillimeter Array, or ALMA, have revealed that many of them contain sharply defined rings and gaps. Astronomers have long suspected that some of those structures are the work of hidden planets, but turning those patterns into reliable planet measurements has remained difficult. “These bright rings are not just beautiful structures – they are essentially planetary fingerprints,” said lead author Amena Faruqi, a PhD student in the Astronomy and Astrophysics Group at the University of Warwick. Simulation of a planet embedded in a protoplanetary disc, causing disc material to pile up in a ring exterior to its orbit. (CREDIT: Amena Faruqi / University of Warwick) “We’ve long understood that …