Search results
Results From The WOW.Com Content Network
Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. [ 4][ 5][ 6] Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.
Rajgad Fort 's Citadel, an eroded hill from the Deccan Traps, which are another hypothesized cause of the K–Pg extinction event. The Cretaceous–Paleogene ( K–Pg) extinction event, [ a] also known as the Cretaceous–Tertiary (K–T) extinction, [ b] was the mass extinction of three-quarters of the plant and animal species on Earth [ 2][ 3 ...
An historic switch in the presidential ticket. A polling shift. And a still-undefined nominee. That’s the backdrop to this week’s Democratic convention.
It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name Eocene comes from the Ancient Greek Ἠώς ( Ēṓs, "Dawn") and καινός ( kainós, "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. [ 7][ 8] The Eocene spans the time from the end of the Paleocene Epoch to the ...
The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level.
Juneteenth is a federal holiday in the United States. For decades, activists and congress members (led by many African Americans) proposed legislation, advocated for, and built support for state and national observances. During his campaign for president in June 2020, Joe Biden publicly celebrated the holiday. [ 125]
In 1862, the physicist William Thomson, 1st Baron Kelvin published calculations that fixed the age of Earth at between 20 million and 400 million years. [19] [20] He assumed that Earth had formed as a completely molten object, and determined the amount of time it would take for the near-surface temperature gradient to decrease to its present value.
The timeline of human evolution outlines the major events in the evolutionary lineage of the modern human species, Homo sapiens, throughout the history of life, beginning some 4 billion years ago down to recent evolution within H. sapiens during and since the Last Glacial Period . It includes brief explanations of the various taxonomic ranks in ...