Search results
Results from the WOW.Com Content Network
Earth formed in this manner about 4.54 billion years ago (with an uncertainty of 1%) [25] [26] [4] and was largely completed within 10–20 million years. [27] In June 2023, scientists reported evidence that the planet Earth may have formed in just three million years, much faster than the 10−100 million years thought earlier.
Earth is the only place in the universe known to harbor life, where it exists in myriad environments. [8] [9] The origin of life on Earth was at least 3.5 billion years ago, possibly as early as 3.8-4.1 billion years ago. [2] [3] [4] Since its emergence, life has persisted in several geological environments.
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]
The Earth's magnetic field was established 3.5 billion years ago. The solar wind flux was about 100 times the value of the modern Sun , so the presence of the magnetic field helped prevent the planet's atmosphere from being stripped away, which is what probably happened to the atmosphere of Mars .
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
The rise in oxygen is attributed to photosynthesis by cyanobacteria, which are thought to have evolved as early as 3.5 billion years ago. [ 17 ] The current scientific understanding of when and how the Earth's atmosphere changed from a weakly reducing to a strongly oxidizing atmosphere largely began with the work of the American geologist ...
At first glance, the galaxy appeared in the same direction as a cluster of galaxies known as Abell 2744, which is located about 3.5 billion light-years from Earth.
The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis, ... It is estimated to have occurred between 3.5 and 2.4 billion years ago during the Archean eon, ...