Swiss National Day

This nationwide celebration of the Swiss Confederation is observed with torchlight processions, fireworks, shooting contests, and folkloric events. The day commemorates the occasion in 1291 when representatives of the three original cantons of Schwyz, Uri, and Unterwalden met on the Rutli meadow and swore an oath of alliance and mutual defense to lay the foundations of the Confederation. Discuss

Nemesis

In 1984, paleontologists David Raup and Jack Sepkoski posited that mass extinction events are cyclical, happening about every 26 million years, and are often caused by large impact events—such as the asteroid that may have led to the end of the dinosaurs 65 million years ago. Some astronomers sought to explain the theory with Nemesis, a hypothetical companion star to the Sun about 1.5 light-years away. According to the hypothesis, how was Nemesis responsible for these extinction events? Discuss