It was long thought that "q" was positive, indicating that the expansion is slowing down due to gravitational attraction. This would imply an age of the universe less than 1/"H" (which is about 14 billion years). For instance, a value for "q" of 1/2 (once favoured by most theorists) would give the age of the universe as 2/(3"H"). The discovery in 1998 that "q" is apparently negative means that the universe could actually be older than 1/"H". However, estimates of the age of the universe are very close to 1/"H".