It's not yet clear whether whoever is chosen to succeed Benedict, who cited the frailty of age as the reason for his departure, will also use Twitter to reach out to some of the 1.5 billion Roman Catholics around the world.

CNN: STORY HIGHLIGHTS

On December 5, Russian cosmonaut Roman Romaneko, Canadian astronaut Chris Hadfield and NASA astronaut Tom Marshburn will launch from Kazakhstan to the International Space Station, which will give the station a 6-person crew until March, when Ford, Novitskiy and Tarelkin will leave.

FORBES: Soyuz Launches With New Crew For Space Station

"Toxic deaths cannot be more than 5%, " says Roman Perez-Soler , an oncologist at Mt.

FORBES: Assessing Avastin's Risk

Authorities were still taking no chances and more than 5, 000 police have been patrolling Athens with demonstrators blocked from coming near the city's Roman Catholic cathedral before the Pope's scheduled appearance.

CNN: Pope moves to heal ancient rift