The Hadean is the earliest eon in Earth’s geologic history, spanning from the planet’s formation about 4.56 billion years ago to roughly 4.0 billion years ago. It is characterized by accretion from planetesimals, intense impact bombardment, large-scale core–mantle differentiation, and the establishment of a magma ocean followed by progressive cooling. Direct rock record from this interval is essentially absent, with evidence derived primarily from detrital Hadean zircons and isotopic signatures indicating early crustal recycling and the possible presence of liquid water. The Hadean sets the initial thermal, chemical, and structural conditions for subsequent Archean crustal evolution.
There are many open questions about how our planet formed 4.55 billion years ago: When did plate tectonics start? When did the Earth's mantle begin to vigorously circulate in a process called convection? What was Earth like ...
Earth Sciences
Mar 3, 2026
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Scientists have long known that Earth's core is mostly made of iron, but the density is not high enough for it to be pure iron, meaning lighter elements exist in the core, as well. In particular, it's suspected to be a major ...
Parts of ancient Earth may have formed continents and recycled crust through subduction far earlier than previously thought. New research led by scientists at the University of Wisconsin–Madison has uncovered chemical signatures ...
Earth Sciences
Feb 4, 2026
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Scientists at MIT and elsewhere have discovered extremely rare remnants of "proto Earth," which formed about 4.5 billion years ago, before a colossal collision irreversibly altered the primitive planet's composition and produced ...
Planetary Sciences
Oct 14, 2025
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Earth formed about 4.6 billion years ago, during the geological eon known as the Hadean. The name "Hadean" comes from the Greek god of the underworld, reflecting the extreme heat that likely characterized the planet at the ...
Earth Sciences
Jul 7, 2025
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A team of researchers at the University of Oxford have uncovered crucial evidence for the origin of water on Earth. Using a rare type of meteorite, known as an enstatite chondrite, which has a composition analogous to that ...
Astrobiology
Apr 15, 2025
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When Earth first formed, it was too hot to retain ice. This means all the water on our planet must have originated from extraterrestrial sources. Studies of ancient terrestrial rocks suggest liquid water existed on Earth ...
Astrobiology
Feb 17, 2025
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