The last time three carriers were together in the Pacific was in June, and Navy Cmdr. Ron Flanders said it was rather unusual to have three carriers in the Pacific theatre.
The Pentagon also recently said that the three carriers are "not directed toward any particular threat," and Flanders said the Nimitz's visit had been planned for months, as it has to cross the Pacific to reach its home port at Naval Station Bremerton in Washington state.
When asked if the Nimitz would head straight home or stay in the Pacific for any given period of time, Flanders said only that when the Nimitz travels through the Pacific, it falls under the command of the 7th Fleet.
Carriers often travel in formations called Carrier Strike Groups, as seen below.
A Carrier Strike Group consists of at least one cruiser, six to 10 destroyers and/or frigates, and a Carrier Air Wing. The carriers are used for offensive operations, while the other ships defend the carrier.
The Nimitz, Roosevelt, and Reagan are all currently accompanied by a Carrier Strike Group in the Pacific.
The other is a 20 mm Phalanx Close-In Weapon System, which is the last line of defense against an incoming missile.
Read more about what the CIWS can do here.
Source: US Navy
One is the NATO Sea Sparrow missile system, which is a short-range antiaircraft and anti-missile weapon system that fires RIM-7M missiles.
The only real offensive weapons aboard carriers are the aircraft, but they do have two main defensive weapons.
Source: US Navy spokesman Cmdr. Ron Flanders.
And two squadrons of Seahawk helicopters.
Carrier Air Wing 11 is currently assigned to the Nimitz, Carrier Air Wing 17 is on the Roosevelt, and Carrier Air Wing 5 is on the Reagan.
Source:US Navy and US Navy spokesman Cmdr. Ron Flanders.
They are each assigned a Carrier Air Wing, which generally consists of about nine squadrons and five different kinds of the following aircraft.
Source: US Navy
Each carrier has two nuclear reactors that power four steam turbines and shafts that bring the carriers to speeds of more than 34 mph.
Each carrier is about 1,092 feet long, 252 feet wide, and 134 feet from waterline to flight deck.
Source: US Navy
The USS Nimitz, USS Roosevelt, and USS Reagan are all Nimitz-class aircraft carriers.
The Nimitz, which is the US's oldest aircraft carrier, was commissioned in 1975, while the Roosevelt was commissioned in 1986 and the Reagan in 2003.
Source: Business Insider India