Problem 12.13 Sophie Zabar, clairvoyante, cried out in pain at precisely the instant her twin brother, 500 km away, hit his thumb with a hammer. A skeptical scientist observed both events (brother's accident, Sophie's cry) from an airplane traveling at c to the right (Fig. 12.19). Which event occurred first, according to the scientist? How much earlier was it, in seconds?

Problem 12.13 Sophie Zabar, clairvoyante, cried out in pain at precisely the instant her twin brother, 500 km away, hit his thumb with a hammer. A skeptical scientist observed both events (brother's accident, Sophie's cry) from an airplane traveling at c to the right (Fig. 12.19). Which event occurred first, according to the scientist? How much earlier was it, in seconds?