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.

The Solar System is far stranger than most people imagine, from Olympus Mons and Uranus rolling on its side to Jupiter’s ...

A new study suggests Earth formed almost entirely from material in the inner Solar System, challenging the idea that water-rich material from beyond Jupiter played a major role. If correct, Earth’s ...