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The Great Oxidation Event ( GOE) or Great Oxygenation Event, also called the Oxygen Catastrophe, Oxygen Revolution, Oxygen Crisis or Oxygen Holocaust, [2] was a time interval during the Early Earth 's Paleoproterozoic era when the Earth's atmosphere and the shallow ocean first experienced a rise in the concentration of oxygen. [3]
A safety data sheet ( SDS ), [1] material safety data sheet ( MSDS ), or product safety data sheet ( PSDS) is a document that lists information relating to occupational safety and health for the use of various substances and products. SDSs are a widely used type of fact sheet used to catalogue information on chemical species including chemical ...
Key events of the 20th century. The 20th century changed the world in unprecedented ways. The World Wars sparked tension between countries and led to the creation of atomic bombs, the Cold War led to the Space Race and the creation of space-based rockets, and the World Wide Web was created. These advancements have played a significant role in ...
August. August 8 – 24 – The United States compete at the Summer Olympics in Beijing, China and win 36 gold, 39 silver, and 37 bronze medals. Michael Phelps wins his eighth gold medal, breaking the record set by Mark Spitz, and sets the record for the most golds in a single Olympics.
The Cambrian–Ordovician extinction event, also known as the Cambrian-Ordovician boundary event, [1] was an extinction event that occurred approximately 485 million years ago ( mya) in the Paleozoic era of the early Phanerozoic eon. [2] It was preceded by the less-documented (but probably more extensive) End-Botomian mass extinction around 517 ...
30th Street Station in Philadelphia, Amtrak's third-busiest train station in the nation, July 2016. This is a list of the train stations with the highest Amtrak ridership the United States in the fiscal year 2023 (October 2022 to September 2023).
1934 ( MCMXXXIV) was a common year starting on Monday of the Gregorian calendar, the 1934th year of the Common Era (CE) and Anno Domini (AD) designations, the 934th year of the 2nd millennium, the 34th year of the 20th century, and the 5th year of the 1930s decade.
This ice sheet was the primary feature of the Pleistocene epoch in North America, commonly referred to as the ice age. During the Pre-Illinoian Stage, the Laurentide Ice Sheet extended as far south as the Missouri and Ohio River valleys. It was up to 2 mi (3.2 km) thick in Nunavik, Quebec, Canada, but much thinner at its edges, where nunataks ...