Astronomers have captured the earliest known stage of planet formation, using combined observations from NASA’s James Webb Space Telescope and the Atacama Large Millimeter/submillimeter Array in Chile. Their target, the young Sun-like protostar HOPS-315, lies about 1,300 light-years away in the Orion B molecular cloud and is estimated to be only ≈100,000 years old. Infrared spectra from Webb and millimetre-wave data from ALMA revealed silicon monoxide gas condensing into crystalline silicate grains within the star’s innermost protoplanetary disk—materials analogous to those that seeded meteorites in the early Solar System. The minerals were detected in a region comparable to the asteroid belt’s orbit, indicating the ‘t = 0’ moment when solid building blocks of planets first emerge. “For the first time, we have identified the earliest moment when planet formation is initiated around a star other than our Sun,” said lead researcher Melissa McClure of Leiden University. The findings, reported in the journal Nature, give scientists a direct laboratory for testing models of how rocky worlds and gas-giant cores begin to assemble, offering a glimpse of processes that shaped the Solar System 4.6 billion years ago.