Born into exceptional privilege, Belle Burden had it all: love, money, family. Then her marriage fell apart. By Alex Kuczynski Sara Levine’s “The Hitch” is a winningly zany portrait of a know-it-all ...

The velocity of light in vacuum, c, is approximately 3 × 10 8 m s −1, fast enough to make 7.5 round-the-world trips in a single second, and to move a distance of 300 mm in 1 ns. This ultrahigh speed ...