Impressive Hadean Eon Facts For Kids About Earth's History

The Hadean is a geologic eon that preceded the Archean in Earth's history.

As per the International Commission on Stratigraphy, it began with the birth of the Earth around 4.6 billion years ago and concluded 4 billion years ago (ICS). Scientists have long assumed that the Solar System bodies formed from a spinning cloud of dust and gases known as an accretion disk during the Hadean epoch.

Heavier and lighter elements pulled together at the cloud's core due to gravitational attraction until nuclear fusion lit it ablaze with light and heat. This, of course, was the moment the Sun was born from the solar nebula.

Gravity shaped our Solar System from a cloud of dust. The terrestrial planets were closer to the Sun than the other planets.

The four eons were known as the Hadean Eon, the Archean Eon, the Proterozoic Eon, and finally the Phanerozoic Eon. An eon as a unit of time has 0.5 billion years or more in it.

If you want to read some fun facts about the Hadean Eon, you should read further about it in detail. There is a lot of such information available on this topic, and geologic eon found here.

Hadean Eon Life Period History

It was believed to be an unofficial geological epoch that occurred immediately before the Archean period.

• The Hadean period started with the creation of the Earth approximately 4.5 billion years ago (Ga) and concluded around 3.8 Ga.
• However, the latter date varies depending on the source. Hadean is derived from 'Hades', the Greek word for 'underworld', and refers to the planet's horrific circumstances at the time.
• Preston Cloud, a geologist, created the word in 1972. W. Brian Harland subsequently classed the time as the Priscoan period.
• Oceans would have developed as soon as the temperatures were conducive. Frequent collisions are considered to have maintained the Earth in a molten condition until the end of the eon.
• The extraordinary resemblance between the Earth's crust and the Moon's structure, the low iron content in the Moon's center, and the Earth-Moon system's high angular momentum support this giant impact hypothesis.
• The vast quantity of rocky and frozen debris existing in the early Solar System might explain the overall absence of Hadean rocks (older than 3800 mya). This eon has no known life forms.

Hadean Eon Age Description

There is no formal subdivision since this eon has scant geological traces on the Earth's surface. However, since the lunar geologic time scale includes multiple major Hadean divisions, these terms are also used interchangeably to indicate the same periods on Earth.

• From the development of the Moon's early crust (4,533 million years ago) until around 3,920 million years ago, it was Pre-Nectarian.
• According to the theory, during the Late Massive Bombardment's fall, Nectarian eras spanned from 3,920 million years ago to around 3,850 million years ago.
• In 2010, an alternate scale was developed that included the Chaotian and Prenephelean Eons before the Hadean and divided the Hadean into three eras, each with two periods.
• The Paleohadean Era consists of the Jacobian (4.4–4.3 Ga) and Hephaestean (4.5–4.4 Ga) phases.
• The Procrustean (4.2–4.1 Ga) and the Canadian (4.3–4.2 Ga) eras make up the Mesohadean.
• Finally, the Promethean (4.0–3.9 Ga) and the Acastan (4.1–4.0 Ga) eras make up the Neohadean.

Hadean Eon Known For

Due to the atmospheric pressure of the thick carbon dioxide atmosphere, seas that existed during this epoch had uncomfortable surface temperatures of about 446 °F (230 °C). A lot of major events happened, as listed below.

• Subduction and dissolving in ocean water eliminated the majority of CO2 from the atmosphere when the Earth finished its cooling.
• On the other hand, strong levels changed widely when new surface and mantle cycles emerged from the molten surface of Early Earth.
• The heavier molten iron sunk into the core as the Earth cooled and attained cooler surface temperature, while lighter rock rose to the top, cooled, and created the crust.
• The oldest known Earth rocks are approximately 3.8 billion years old.
• However, according to a study of zircons published in September 2008, Australian Hadean rock contains minerals that suggest plate tectonics existed as prematurely as 4,000 million years ago.

Atmosphere And Climate Of Earth During Hadean Eon

Geologists believe liquid water oceans existed for at least 4.4 Ga during the Hadean Eon based on zircon research. Water would have been present in significant quantities in the material that created the Earth.

• When the young planet Earth was less massive during its origin, water molecules might have escaped Earth's gravity more readily.
• There was no oxygen at this time, it mostly had poisonous gases like methane or ammonia, which could have killed you if you lived in it!
• The collision that produced the Moon has disturbed part of the ancient planet, leading to the molten state of one or two huge sections of the earliest Earth.
• Because it is impossible to liquefy and mix huge rock masses thoroughly, the Earth's current composition shows that nothing could have caused solid rock melting when Earth formed.
• However, this collision should have evaporated a significant amount of material, forming a rock vapor atmosphere surrounding the infant planet.
• Within two thousand years, the rock vapor would have condensed, leaving behind hot volatiles and a partially molten surface that would have resulted in a strong CO 2 atmosphere with water vapor and hydrogen.
• Even after a surface temperature of 446 °F (230 °C), liquid water seas persisted because water is still liquid at atmospheric pressure of over 27 atmospheres, produced by the high CO2 atmosphere.
• Dissolving and subduction in ocean water eliminated the majority of CO2 from the atmosphere as the planet cooled.

Did You Know...

• During the Precambrian, life had just barely begun. Nonanimal protists and bacteria made up the majority of Precambrian life. At the end of this era, oceans were formed as water in the atmosphere condensed.
• Eon is a unit of time that has a billion years in geology.
• The Paleozoic era, which lasted from 540 million to 248 million years ago, is the oldest era.
• The Precambrian is the Earth's longest eon since it is split into numerous eons.