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The thermosphere (or the upper atmosphere) is the height region above 85 kilometres (53 mi), while the region between the tropopause and the mesopause is the middle atmosphere (stratosphere and mesosphere) where absorption of solar UV radiation generates the temperature maximum near an altitude of 45 kilometres (28 mi) and causes the ozone layer.
First known remains of biotic life (discovered in 4.1 billion-year-old rocks in Western Australia). [5] [6] ... Timeline of the evolutionary history of life;
As for life on land, in 2019 scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants are thought to have been living on land. [99] [100] [101] The earliest life on land may have been bacteria 3.22 billion years ago. [102]
Visual representation of the Logarithmic timeline in the scale of the universe. This timeline shows the whole history of the universe, the Earth, and mankind in one table. Each row is defined in years ago, that is, years before the present date, with the earliest times at the top of the chart. In each table cell on the right, references to ...
In physical cosmology, the age of the universe is the time elapsed since the Big Bang.Astronomers have derived two different measurements of the age of the universe: [1] a measurement based on direct observations of an early state of the universe, which indicate an age of 13.787 ± 0.020 billion years as interpreted with the Lambda-CDM concordance model as of 2021; [2] and a measurement based ...
The biosphere is postulated to have developed, from the origin of life onwards, at least some 3.5 billion years ago. [74] The earliest evidence for life on Earth includes biogenic graphite found in 3.7 billion-year-old metasedimentary rocks from Western Greenland [ 69 ] and microbial mat fossils found in 3.48 billion-year-old sandstone from ...
The span of recorded history is roughly five thousand years, beginning with the earliest linguistic records in the third millennium BC in Mesopotamia and Egypt. Classical antiquity – Broad term for a long period of cultural history centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome ...
The earliest life on Earth arose at least 3.5 billion years ago. [16] [17] [18] Earlier possible evidence of life includes graphite, which may have a biogenic origin, in 3.7-billion-year-old metasedimentary rocks discovered in southwestern Greenland [19] and 4.1-billion-year-old zircon grains in Western Australia. [20] [21]