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The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [ 5] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
University of Arizona Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. [ 1] It is a 3.14-acre (1.27-hectare) [ 2] structure originally built to ...
Carvings on a 12,000-year-old monument in Turkey appear to mark solar days and years, making it possibly the oldest solar calendar in ancient civilization. Marking a massive comet strike as the ...
The Geologic Calendar is a scale in which the geological timespan of the Earth is mapped onto a calendrical year; that is to say, the day one of the Earth took place on a geologic January 1 at precisely midnight, and today's date and time is December 31 at midnight. [1] On this calendar, the inferred appearance of the first living single-celled ...
Since each lunation is approximately 29 + 1 ⁄ 2 days, [1] it is common for the months of a lunar calendar to alternate between 29 and 30 days. Since the period of 12 such lunations, a lunar year , is 354 days, 8 hours, 48 minutes, 34 seconds (354.36707 days), [ 1 ] purely lunar calendars are 11 to 12 days shorter than the solar year .
Map of ongoing armed conflicts (number of combat-related deaths in current or previous year): Major wars (10,000 or more) Wars (1,000–9,999) Minor conflicts (100–999) Skirmishes and clashes (1–99) The following is a list of ongoing armed conflicts that are taking place around the world.
Stars are known to get brighter as they age, and the Sun has become 30% brighter since its formation 4.5 billion years ago. [70] Many models indicate that the early Earth should have been covered in ice. [71] [66] A likely solution is that there was enough carbon dioxide and methane to produce a greenhouse effect. The carbon dioxide would have ...
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites