many people seem to be under the impression that a life sentence means only 8 years.
Actually, a life sentence does mean life, in that their sentence hangs over them for life and is never expunged. In really severe cases, the judge can order a 'whole life sentence', which means the prisoner will never be released. The majority of life prisoners are given a minimum term of imprisonment, but are released on lifetime parole. That means they're monitored and any reoffending, or breaking the terms of their parole, will immediately send them back to prison for an indefinite period without any further trial.