Here's why:

* 76-year Orbit: Halley's Comet is famous for its relatively short orbital period of approximately 76 years.

* Visibility: It's visible from Earth during its perihelion (closest approach to the Sun), which happens roughly every 76 years.

* 2008: Halley's Comet last visited our skies in 1986 and won't be back until sometime around 2061.

So, while Halley's Comet is indeed visible every 76 years, it wasn't visible in 2008.