I’m a space enthusiast, and from what I’ve learned here’s the breakdown: solar systems take millions of years to form. It all starts in a nebula where gas collapses and coalesces into a star and surrounding material. The process is long and complex (and not fully understood), but we know it eventually produces rocky planets, gas giants, and smaller debris.

This new paper reports something exciting, they’ve spotted a moment that signals the beginning of rocky planet formation. In the system HOPS-315, gas has cooled enough for solids to condense, which is when planet formation kicks off. This happens about twice as far from its baby star as Earth is from the Sun.

And of course, ALMA, the telescope that made the discovery, is fantastic at catching solar systems in the act of forming. It was only a matter of time before this stage was observed.