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Dresbachian extinction event: 502 Ma: End-Botomian extinction event: 517 Ma: Precambrian: End-Ediacaran extinction: 542 Ma: Anoxic event [45] Great Oxygenation Event: 2400 Ma: Rising oxygen levels in the atmosphere due to the development of photosynthesis as well as possible Snowball Earth event. (see: Huronian glaciation.)
Strong extinction in Earth's atmosphere of some wavelength regions (such as X-ray, ultraviolet, and infrared) is overcome by the use of space-based observatories. Since blue light is much more strongly attenuated than red light, extinction causes objects to appear redder than expected; this phenomenon is called interstellar reddening. [5]
The most famous of these mass extinction events — when an asteroid slammed into Earth 66 million years ago, dooming the dinosaurs and many other species — is also the most recent. But ...
The Solar System is traveling at an average speed of 230 km/s (828,000 km/h) or 143 mi/s (514,000 mph) within its trajectory around the Galactic Center, [3] a speed at which an object could circumnavigate the Earth's equator in 2 minutes and 54 seconds; that speed corresponds to approximately 1/1300 of the speed of light.
An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth.Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms.
There is a 50% chance that such a lethal GRB took place within two kiloparsecs of Earth during the last 500 million years, causing one of the major mass extinction events. [ 155 ] [ 16 ] The major Ordovician–Silurian extinction event 450 million years ago may have been caused by a GRB.
There are billions of stars in the Milky Way similar to the Sun. [7] [8] With high probability, some of these stars have Earth-like planets in a circumstellar habitable zone. [9] Many of these stars, and hence their planets, are much older than the Sun. [10] [11] If Earth-like planets are typical, some may have developed intelligent life long ago.
From the total of 5,086 stars known to have exoplanets (as of January 26, 2024), there are a total of 1,033 known multiplanetary systems, [1] or stars with at least two confirmed planets, beyond the Solar System. This list includes systems with at least three confirmed planets or two confirmed planets where additional candidates have been proposed.