Short answers, pulled from the story.
The Polish Golden Age began in the late 15th century as part of the broader European Renaissance. Historians place its end in the mid-17th century, when the Commonwealth was devastated by the Khmelnytsky Uprising of 1648-57 and simultaneous Swedish and Russian invasions.
By the 16th century the Commonwealth covered 1 million square kilometers with a population of 11 million. At its greatest extent it stretched from modern-day Estonia in the north to Moldavia in the south, and from near Moscow in the east to Brandenburg in the west.
The liberum veto was a rule in the Commonwealth parliament allowing any single Sejm deputy to nullify all legislation passed during that session by voicing opposition. It was used for the first time in 1669. During the political crisis of the late 17th century, nobles could also deploy it in provincial sejmiks.
Copernicus published De revolutionibus orbium coelestium in Nuremberg in 1543, displacing the Ptolemaic model and opening scientific inquiry. He drew his early inspiration at the University of Kraków, later studied in Italy, and spent his astronomical career working at Frauenburg, where he died.
Jan Kochanowski was born in 1530 into a prosperous noble family and became one of the greatest Polish poets of all time. He studied at Kraków, Königsberg, and Padua, served as a royal secretary, and later settled in his family village of Czarnolas. His most celebrated works are the Threnodies, laments written after the death of his young daughter.
Golden Liberty, in Polish Zlota Wolnosc, was the political system of the Commonwealth in which all nobility were considered legally equal regardless of wealth. It included free royal elections open to all nobles, a parliament the king was required to convene every two years, religious freedom guaranteed by the Warsaw Confederation Act of 1573, and the right of szlachta to rebel legally against a king who violated their freedoms.