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This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago. Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods , respectively.
500 million years of climate change [7] The Phanerozoic eon, encompassing the last 542 million years and almost the entire time since the origination of complex multi-cellular life, has more generally been a period of fluctuating temperature between ice ages, such as the current age, and "climate optima", similar to what occurred in the ...
The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
6 × 10 43 Qs (2 × 10 66 years): The approximate lifespan of a black hole with the mass of the Sun [21] 4 × 10 63 Qs (1.3 × 10 86 years): The approximate lifespan of Sagittarius A*, if uncharged and non-rotating [21] 5.4 × 10 83 Qs (1.7 × 10 106 years): The approximate lifespan of a supermassive black hole with a mass of 20 trillion solar ...
The numeric values on the International Chronostratigrahpic Chart are represented by the unit Ma (megaannum, for 'million years'). For example, 201.4 ± 0.2 Ma, the lower boundary of the Jurassic Period, is defined as 201,400,000 years old with an uncertainty of 200,000 years.
The Pleistocene (/ ˈ p l aɪ s t ə ˌ s iː n,-s t oʊ-/ PLY-stə-seen, -stoh-; [4] [5] referred to colloquially as the Ice Age) is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations.
Download as PDF; Printable version; ... There are 60 minutes in an hour, and 24 hours in a day. ... a few localities continued to use decimal time for six years for ...