CAPE CANAVERAL, Fla. — Astronomers have discovered the earliest seeds of rocky planets forming in the gas around a baby sun-like star, providing a precious peek into the dawn of our own solar system. It’s an unprecedented snapshot of “time zero,” scientists reported Wednesday, when new worlds begin to gel.

Peering through a cosmic keyhole at distant baby star, astronomers may have opened a new window on the deep past of our own solar system. Weighing in at 0.6 solar mass, HOPS-315 should someday grow to become a star much like our own sun;