Webb’s mid-infrared spectra cover 21 young stars surrounded by “extreme debris discs”: hot dust from collisions between growing rocky worlds, seen around only about 1% of young stars. The discs share small grains, plenty of warm dust close to the star and erratic brightness changes; a third are silica-rich and appear only around stars younger than 300 million years. Our take: this is how rocky planets like Earth get built, one violent impact at a time.
21young star systems
~1%of young stars show it
1/3silica-rich discs