Search results
Results from the WOW.Com Content Network
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth itself.
The age of Earth is about 4.54 billion years; [7] [33] [34] the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago according to the stromatolite record. [35] Some computer models suggest life began as early as 4.5 billion years ago. [36] [37] The oldest evidence of life is indirect in the form of isotopic ...
This is a list of dates associated with the prehistoric peopling of the world (first known presence of Homo sapiens). The list is divided into four categories, Middle Paleolithic (before 50,000 years ago), Upper Paleolithic (50,000 to 12,500 years ago), Holocene (12,500 to 500 years ago) and Modern ( Age of Sail and modern exploration).
Overview map of the peopling of the world by early humans during the Upper Paleolithic, following the Southern Dispersal paradigm. The so-called "recent dispersal" of modern humans took place about 70–50,000 years ago. [60] [61] [62] It is this migration wave that led to the lasting spread of modern humans throughout the world.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
So to understand how we came to exist on planet Earth, we'll need to know how Earth managed to stay fit for life for billions of years. Earth has been habitable for billions of years ...
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [177] [178] [179] including in comets, [180] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA ...
Two teams of scientists have discovered a theoretically habitable planet called Gliese 12b that’s smaller than Earth but bigger than Venus, just 40 light-years away.