Drop The Bomb Meaning

Example: Used other than as an idiom: see drop,‎ bomb.
To reveal dramatic and unexpected news that changes a situation completely.
2011, Chris Myers Asch, The Senator and the Sharecropper, ISBN 0807878057:
  A mere two months after the New Orleans hearings, the Supreme Court dropped the bomb that Eastland and other white southerners feared: Brown. Much as the Chinese Communists' victory and the Russian's building of the atomic bomb in 1949 had ignited the Cold War and anti-Communism, the Brown decision took the struggle for and against black freedom to a new level of intensity.
2011, Cege Smith, Edge of Shadows, ISBN 9781467940603:
  Melanie dropped the bomb. "His buddy was a Mr. Henry Decatur."
2014, Mary Kay Andrews, Save the Date, ISBN 1250019680:
  Sylvia finally returned my calls yesterday, and while I was in the middle of chewing her out about the airconditioning, she dropped the bomb. Said it didn't matter because she'd sold the building.
Gail Sattler, 2014, The Best Man's Holiday Romance, ISBN 1488718512:
  Natasha gulped and tried to look cheerful when she dropped the bomb on him. “Four down, forty-six to go.” Jeff froze. “Excuse me? Did I hear you right? That means you have to buy fifty Christmas presents?”
2014, Rexanne Becnel, The Christmas Train, ISBN 1476779848:
  Then she'd dropped the bomb: she was pregnant.