Universe's 'standard candles' are white dwarf mergers

Universe's 'standard candles' are white dwarf mergers: ...the new study by American, Israeli and Japanese astronomers using Subaru and Keck telescopes in Hawaii instead suggests that many, if not most, of the Type Ia supernovae result when two white dwarf stars merge and annihilate in a thermonuclear explosion.

Though the two-faced nature of Type Ia supernovae still allows them to be used as calibratable candles to measure cosmic distance, Filippenko said, it might affect attempts to “quantify in detail the history of the expansion rate of the universe. The subtle differences between single- and double-degenerate models could introduce a systematic error that we’ll need to account for.”