Intercalation
101Fullerene — Buckminsterfullerene C60 (left) and carbon nanotubes (right) are two examples of structures in the fullerene family …
102Gregorian calendar — For the calendar of religious holidays and periods, see Liturgical year. For this year s Gregorian calendar, see Common year starting on Saturday. 2011 in other calendars Gregorian calendar 2011 MMXI …
103Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… …
104Julian calendar — The Julian calendar began in 45 BC (709 AUC) as a reform of the Roman calendar by Julius Caesar. It was chosen after consultation with the astronomer Sosigenes of Alexandria and was probably designed to approximate the tropical year (known at… …
105Longitude — For Dava Sobel s book about John Harrison, see Longitude (book). For the adaptation of Sobel s book, see Longitude (TV series). Map of Earth Longitude (λ) Lines of longitude appear vertical with varying curvature in this projection, but are… …
106Minute — This article is about the unit of time, angle and right ascension. For other uses of the word, see Minute (disambiguation). See also: Minute of arc A minute is a unit of measurement of time or of angle. The minute is a unit of time equal to… …
107Month — For the Egyptian hawk god, see Monthu. A month is a unit of time, used with calendars, which was first used and invented in Mesopotamia, as a natural period related to the motion of the Moon; month and Moon are cognates. The traditional concept… …
108Metonic cycle — Heliocentric Solar System In astronomy and calendar studies, the Metonic cycle or Enneadecaeteris (from Greek words for nineteen years) is a period of very close to 19 years which is remarkable for being very nearly a common multiple of the solar …
109Roman calendar — The Roman calendar changed its form several times in the time between the founding of Rome and the fall of the Roman Empire. This article generally discusses the early Roman or pre Julian calendars. The calendar used after 46 BC is discussed …
110Second — This article is about the unit of time. For other uses, see Second (disambiguation). A light flashing approximately once per second. The second (SI unit symbol: s; informal abbreviation: sec) is a unit of measurement of time, and is the… …
