Astronaut youngest person to fly in space is Gherman Titov, who was 25 years old when he flew Vostok 2. (Titov was also the first person to suffer space sickness). The oldest person who has flown in space is John Glenn, who was 77 when he flew on STS-95. 438 days is the longest time spent in space, by Russian Valeri Polyakov. As of 2006, the most spaceflights by an individual astronaut is seven, a record held by both Jerry L. Ross and Franklin Chang-Diaz. The farthest distance from Earth an astronaut has traveled was , when Jim Lovell, Jack Swigert,
Chinese as a foreign language (one year and about 8 months), to learn Mandarin. A quote attributed to William Milne, Morrison's colleague, goes that learning Chinese is Several major difficulties stand out: While English uses an alphabet, Chinese uses "hanzi", or Chinese characters, as its writing system. The "Kangxi dictionary" contains 47,035 characters (). However, most of the characters contained there are archaic and obscure. The Chart of Common Characters of Modern Chinese (), promulgated in People's Republic of China, lists 2,500 common characters and 1,000 less-than-common characters, while the Chart of Generally Utilized Characters of Modern Chinese () lists 7,000 characters, including the 3,500