Year zero
ISO 8601:2004 (and previously ISO 8601:2000, but not ISO 8601:1988) explicitly uses astronomical year numbering in its date reference systems. Because it also specifies the use of the proleptic Gregorian calendar for all years before 1582, some readers incorrectly assume that a year zero is also included in that proleptic calendar, but it is not used with the BC/AD era. The "basic" format for year 0 is the four-digit form 0000, which equals the historical year 1 BC. Several "expanded" formats are possible: −0000 and +0000, as well as five- and six-digit versions. Earlier years are also negative four-, five- or six-digit years, which have an absolute value one less than the equivalent BC year, hence -0001 = 2 BC. Because only ISO 646 (7-bit ASCII) characters are allowed by ISO 8601, the minus sign is represented by a hyphen-minus.
Zero: The Biography of a Dangerous Idea
Zero: The Biography of a Dangerous Idea is a book by American author and journalist Charles Seife. The book offers a comprehensive look at number 0 and its controversing role as one of the great paradoxes of human thought and history since its invention by the ancient Babylonians. Even though zero is a fundamental idea for the modern science, initially the notion of a complete absence got a largely negative, sometimes hostile, treatment by the Western world and Greco-Roman philosophy. "Zero" won 2001 PEN/Martha Albrand Award for First Nonfiction Book.