Zhane was the Silver Power Ranger. His whereabouts are currently unknown.
Power Rangers in Space - 1998 Zhane's Destiny 1-24 was released on: USA: 16 October 1998
There is no Silver Ranger in Mighty Morphin Power Rangers the first Silver Ranger that appears in the Power Rangers is during the Power Rangers In Space season in which the Space Rangers come across an unconscious Silver Ranger who Andros reveals that the Silver Ranger is named Zhane and they were best friends but when Dark Specter had invaded their world of KO-35 Zhane had taken an attack that was meant for him and the attack nearly killed him and Andros provides that he set up the machine that he was in with the intention of attempting to save his life but he states that there was no guarantee of Zhane ever awakening from his frozen slumber.
The names of the Power Rangers in Power Rangers In Space are Carlos as the Black Space Power Ranger, Cassie Chan as the Pink Space Power Ranger, Theodore Jay "T.J." Jarvis Johnson the Blue Space Power Ranger, Ashley Hammond the Yellow Space Power Ranger, Andros the Red Space Power Ranger and Zhane the Silver Space Power Ranger.
Yes, the majority of Power Rangers are from Earth however ones such as the Alien Rangers along with Trey, Andros, Zhane, Maya, Karone, Trip and Tyzonn are not from Earth. The majority of the Power Rangers' powers are not from Earth as well since the Zeo Crystal comes from another alien race, the Turbo powers are created apparently by Zordon since their source is his home planet, the Quasar Sabers are an alien source and the Dino Gems are from an asteroid.
Andros - Power Rangers - was created in 1998.
Org - Power Rangers - was created in 2002.
Power Rangers Turbo was created on 1997-04-19.
Villains in Power Rangers Turbo was created in 1997.
Power Rangers S.P.D. was created on 2005-02-05.
Power Rangers RPM was created on 2009-03-07.
Villains in Power Rangers RPM was created in 2009.