What is implied malice murder in second degree murder?

California law recognizes three theories of second degree murder, one of which is implied malice murder. ( People v. Robertson (2004) 34 Cal.4th 156, 164, 17 Cal.Rptr.3d 604, 95 P.3d 872 [malice is implied when the killing results from an intentional act, the natural consequences of which are dangerous to life, which act was deliberately performed by a person who knows that his conduct endangers the life of another and who acts with conscious disregard for life].)