Iron catastrophe
Encyclopedia
The iron catastrophe was a major event early in the history of Earth
. After accumulation of the Earth
's material into a spherical mass, the material was mostly uniform in composition. While residual heat from the collision of the material that formed the Earth was significant, heating from radioactive materials in this mass further increased the temperature until a critical condition was reached, when the material was molten enough to allow movement. At this point, the denser iron
and nickel
evenly distributed throughout the mass, sank to the centre of the planet to form the core - an important process of planetary differentiation
. The gravitational potential energy released by the sinking of the dense NiFe
globules increased the temperature of the protoplanet above the melting point resulting in a global silicate magma
which accelerated the process. This event occurred at about 500 million years into the formation of the planet.
This large spinning mass of super-hot metal is responsible for the magnetosphere
, which protects the Earth from solar wind
and the most harmful components of solar radiation coming from our Sun
. The magnetosphere protects both Earth's atmosphere and life to the present day and distinguishes our planet from a close celestial neighbour, Mars
, which no longer has a significant magnetic field nor comparable atmosphere. Ironically, contrary to the implication of a "catastrophe", this event was necessary for life to emerge and evolve on Earth for, without it, the atmosphere would have also been stripped from the Earth long before the present epoch.
Another theory, however, suggests Mars did once experience its own iron catastrophe and was once shielded by a magnetosphere. By this theory Mars has simply cooled faster than the Earth and has solidified its spinning iron center into sync with its continental crust, gradually shutting down its magnetosphere. The finding of signs of liquid water once existing on Mars suggests that it once had its own magnetic shield to keep the water in the atmosphere of the planet from being blown into space by solar wind.
History of Earth
The history of the Earth describes the most important events and fundamental stages in the development of the planet Earth from its formation 4.578 billion years ago to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of the Earth's...
. After accumulation of the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's material into a spherical mass, the material was mostly uniform in composition. While residual heat from the collision of the material that formed the Earth was significant, heating from radioactive materials in this mass further increased the temperature until a critical condition was reached, when the material was molten enough to allow movement. At this point, the denser iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
evenly distributed throughout the mass, sank to the centre of the planet to form the core - an important process of planetary differentiation
Planetary differentiation
In planetary science, planetary differentiation is the process of separating out different constituents of a planetary body as a consequence of their physical or chemical behaviour, where the body develops into compositionally distinct layers; the denser materials of a planet sink to the center,...
. The gravitational potential energy released by the sinking of the dense NiFe
NiFe
NiFe or Nife is a general shorthand expression for a mixture of nickel and iron . NiFe is used to describe nickel-iron batteries, various chemical reactions that involve a nickel-iron catalyst or component, and in geology to describe the general composition of the Earth's core.The affinity of...
globules increased the temperature of the protoplanet above the melting point resulting in a global silicate magma
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...
which accelerated the process. This event occurred at about 500 million years into the formation of the planet.
This large spinning mass of super-hot metal is responsible for the magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
, which protects the Earth from solar wind
Solar wind
The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
and the most harmful components of solar radiation coming from our Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. The magnetosphere protects both Earth's atmosphere and life to the present day and distinguishes our planet from a close celestial neighbour, Mars
Mars
Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
, which no longer has a significant magnetic field nor comparable atmosphere. Ironically, contrary to the implication of a "catastrophe", this event was necessary for life to emerge and evolve on Earth for, without it, the atmosphere would have also been stripped from the Earth long before the present epoch.
Another theory, however, suggests Mars did once experience its own iron catastrophe and was once shielded by a magnetosphere. By this theory Mars has simply cooled faster than the Earth and has solidified its spinning iron center into sync with its continental crust, gradually shutting down its magnetosphere. The finding of signs of liquid water once existing on Mars suggests that it once had its own magnetic shield to keep the water in the atmosphere of the planet from being blown into space by solar wind.