What Lights the Universe’s Standard Candles?

Every year, around 1,000 Type Ia supernovas erupt in the sky. These stellar explosions brighten and then fade away in a pattern so repeatable that they’re used as “standard candles” — objects so uniformly bright that astronomers can deduce the distance to one of them by its appearance. Our understanding of the cosmos is based on these standard candles. Consider two of the biggest mysteries in…

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