Geologic 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… … Wikipedia
Calendar — For other uses, see Calendar (disambiguation). For the Gregorian calendar for this year, see Common year starting on Saturday. A page from the Hindu calendar 1871–1872. A calendar is a system of organizing days for social, religious, commercial,… … Wikipedia
Geologic record — The layer cake like appearance of concordant strata laid down over hundreds of thousands of years … Wikipedia
geologic time — the succession of eras, periods, and epochs as considered in historical geology. [1860 65] * * * Interval of time occupied by the Earth s geologic history, extending from с 3. 9 billion years ago (corresponding to the age of the oldest known… … Universalium
Calendar of 1993 — ▪ 1994 January January 1 Czechoslovakia now two nations. What had been the single nation of Czechoslovakia officially became two independent states, the Czech Republic and Slovakia. Vaclav Havel, the former president of Czechoslovakia, and… … Universalium
Gregorian 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 … Wikipedia
Islamic calendar — Arabic calendar redirects here. For the Gregorian calendar in Arabic, see Arabic names of calendar months. This … Wikipedia
Julian 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… … Wikipedia
Lunar calendar — A lunar calendar is a calendar that is based on cycles of the lunar phase. A common purely lunar calendar is the Islamic calendar or Hijri calendar. A feature of the Islamic calendar is that a year is always 12 months, so the months are not… … Wikipedia
Revised Julian calendar — The Revised Julian calendar, also known as the Rectified Julian calendar, or, less formally, New calendar, is a calendar, originated in 1923, which effectively discontinued the 340 years of divergence between the naming of dates sanctioned by… … Wikipedia
