Readers ask about dust in space, playgrounds, and COVID-19

Not your bookshelf’s dust

Dust may explain why the star Betelgeuse suddenly dimmed in 2019, Lisa Grossman reported in “Betelgeuse is not about to explode” (SN: 4/11/20, p. 6).

Reader Steve Ostrom was intrigued by how gas clouds around red giant stars like Betelgeuse condense into dust.