- How bright did Nova Aquila 1918 become, and how did that compare to previous novae like Kepler's star?
- What did spectroscopic study of Nova Aquila's dimming reveal about the expanding shell of gas?
- What modern explanation for novae — involving a white dwarf and a companion star — replaced the 1918 understanding?
Supernovae
The explosive deaths of stars.
- What is the Chandrasekhar limit, and why can't a white dwarf above roughly 1.4 solar masses hold itself together?
- Why did Arthur Eddington publicly reject Chandrasekhar's calculation, and how was he ultimately shown to be wrong?
- Why did the 1983 Physics Prize pair a theory of stellar collapse with a theory of element formation?
- How did Ian Shelton first notice Supernova 1987A at Las Campanas Observatory?
- Why did neutrino detectors in Japan and Ohio register a burst of particles three hours before the supernova's light arrived?
- What made SN 1987A significant compared to supernovae observed since Kepler's in 1604?
- How did the neutrino burst confirm decades of theoretical predictions about core-collapse supernovae?
- How might the planets around PSR B1257+12 have survived or formed after the supernova?
- Why are Type Ia supernovae useful as 'standard candles' for measuring cosmic distances?
- What did both the Supernova Cosmology Project and the High-Z Supernova Search Team find when they measured distant supernovae?
- What was the first object Chandra imaged, and why did its resolution mark such an advance?
- Why is the observatory named after Subrahmanyan Chandrasekhar?
- What did Masatoshi Koshiba's detection of neutrinos from a 1987 supernova prove for the first time?
- How did astronomers use Type Ia supernovae to measure the expansion rate of the universe?
- What is a kilonova, and what did its spectrum reveal about heavy-element formation?