A floating point literal is a character-string whose value is specified
  by 4 to 37 characters selected from the digits 0 to 9, the plus sign,
  the minus sign, the decimal point and the letter E (upper or lower
  case).

  The value of a floating point literal is the algebraic quantity
  represented by the characters in the literal that precede the "E"
  multiplied by ten raised to the power of the algebraic quantity
  represented by the characters in the literal following the "E".