section_path: History of exploration/Antarctic expeditions
section_name: Antarctic expeditions
paragraph_text: Antarctic expeditions
  
  In December 1839, as part of the United States Exploring Expedition of 1838–42 conducted by the United States Navy (sometimes called "the Wilkes Expedition"), an expedition sailed from Sydney, Australia, on the sloops-of-war USS Vincennes and USS Peacock, the brig USS Porpoise, the full-rigged ship Relief, and two schooners Sea Gull and USS Flying Fish. They sailed into the Antarctic Ocean, as it was then known, and reported the discovery "of an Antarctic continent west of the Balleny Islands " on 25 January 1840. That part of Antarctica was later named " Wilkes Land ", a name it maintains to this day.
  
  Explorer James Clark Ross passed through what is now known as the Ross Sea and discovered Ross Island (both of which were named for him) in 1841. He sailed along a huge wall of ice that was later named the Ross Ice Shelf. Mount Erebus and Mount Terror are named after two ships from his expedition: HMS Erebus and HMS Terror.
  
  The Imperial Trans-Antarctic Expedition of 1914, led by Ernest Shackleton, set out to cross the continent via the pole, but their ship, Endurance, was trapped and crushed by pack ice before they even landed. The expedition members survived after an epic journey on sledges over pack ice to Elephant Island. Then Shackleton and five others crossed the Southern Ocean, in an open boat called James Caird, and then trekked over South Georgia to raise the alarm at the whaling station Grytviken.
  
  In 1946, US Navy Rear Admiral Richard E. Byrd and more than 4,700 military personnel visited the Antarctic in an expedition called Operation Highjump. Reported to the public as a scientific mission, the details were kept secret and it may have actually been a training or testing mission for the military. The expedition was, in both military or scientific planning terms, put together very quickly. The group contained an unusually high amount of military equipment, including an aircraft carrier, submarines, military support ships, assault troops and military vehicles. The expedition was planned to last for eight months but was unexpectedly terminated after only two months. With the exception of some eccentric entries in Admiral Byrd's diaries, no real explanation for the early termination has ever been officially given.
  
  Captain Finn Ronne, Byrd's executive officer, returned to Antarctica with his own expedition in 1947–1948, with Navy support, three planes, and dogs. He disproved the notion that the continent was divided in two and established that East and West Antarctica was one single continent, i.e. that the Weddell Sea and the Ross Sea are not connected. The expedition explored and mapped large parts of Palmer Land and the Weddell Sea coastline, and identified the Ronne Ice Shelf, named by him for his wife Jackie Ronne. He covered 3,600 miles (5,790 km) by ski and dog sled – more than any other explorer in history. The Ronne Antarctic Research Expedition discovered and mapped the last unknown coastline in the world and was the first Antarctic expedition to ever include women.