Explore how cold gas and dust in molecular clouds collapse under gravity, form protostars and disks, ignite nuclear fusion, and become main-sequence stars. Learn how stellar mass shapes each star’s life.

An undergraduate introduction to lasers, covering photon interactions, stimulated emission, population inversion, resonators, laser types, beam properties, applications, limitations, and safety.

Explore how volcanoes form, the parts of a volcano, eruption styles, and major hazards. Learn how scientists monitor volcanic activity and how volcanoes can also create fertile land and resources.

Explore how black holes form, why their gravity is so powerful, and how scientists detect them. Learn about event horizons, accretion disks, stellar and supermassive black holes.

Explore the legendary Trojan War: Paris and Helen, Greek and Trojan heroes, Achilles and Hector, the Trojan Horse, and what archaeology reveals about the ancient city of Troy.