A 'new star' appeared overnight in 1572 and broke 1,800 years of astronomy

Aristotle had taught that the heavens beyond the Moon were fixed and unchanging, a view astronomy still accepted in the 16th century. Tycho Brahe then observed a brilliant new star in Cassiopeia, visible even in daylight, and carefully measured it had no detectable parallax — meaning it sat far among the fixed stars, not nearby. His 1573 book De Nova Stella proved the heavens could change after all.

— Tycho Brahe, De Nova Stella — Observed November 1572; published 1573