The expanding Earth or growing Earth

hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...

argues that the position and relative movement of

continents A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered from largest in area to smallest, these seven ...

is at least partially due to the volume of

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

increasing. Conversely, geophysical global cooling was the hypothesis that various features could be explained by Earth contracting. Although it was suggested historically, since the recognition of

plate tectonics Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...

in the 1970s, scientific consensus has rejected any significant expansion or contraction of Earth.

Different forms of the hypothesis

Expansion with constant mass

In 1834, during the second voyage of HMS ''Beagle'',

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended ...

investigated stepped plains featuring

raised beach A raised beach, coastal terrace,Pinter, N (2010): 'Coastal Terraces, Sealevel, and Active Tectonics' (educational exercise), from 2/04/2011/ref> or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin,P ...

es in

Patagonia Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and g ...

which indicated to him that a huge area of South America had been "uplifted to its present height by a succession of elevations which acted over the whole of this space with nearly an equal force." While his mentor Charles Lyell had suggested forces acting near the crust on smaller areas, Darwin hypothesized that uplift at this continental scale required "the gradual expansion of some central mass" f the earth"acting by intervals on the outer crust" with the "elevations being concentric with form of globe (or certainly nearly so)". In 1835 he extended this concept to include the

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

as part of a curved enlargement of the earth's crust due to "the action of one connected force". Not long afterwards, he moved on from this idea and proposed that as the mountains rose, the ocean floor subsided, explaining the formation of coral reefs. In 1889 and 1909 Roberto Mantovani published a hypothesis of Earth expansion and continental drift. He assumed that a closed continent covered the entire surface of a smaller Earth.

Thermal expansion Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic ...

led to

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

activity, which broke the land mass into smaller continents. These continents drifted away from each other because of further expansion at the rip-zones, where oceans currently lie. Although

Alfred Wegener Alfred Lothar Wegener (; ; 1 November 1880 – November 1930) was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher. During his lifetime he was primarily known for his achievements in meteorology and ...

noticed some similarities to his own hypothesis of

continental drift Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of pl ...

, he did not mention Earth expansion as the cause of drift in Mantovani's hypothesis. A compromise between Earth-expansion and Earth-contraction is the "theory of thermal cycles" by Irish physicist

John Joly John Joly FRS (1 November 1857 – 8 December 1933) was an Irish physicist and professor of geology at the University of Dublin, known for his development of radiotherapy in the treatment of cancer. He is also known for developing techniques to ...

. He assumed that heat flow from radioactive decay inside Earth surpasses the cooling of Earth's exterior. Together with British geologist Arthur Holmes, Joly proposed a hypothesis in which Earth loses its heat by cyclic periods of expansion. In their hypothesis, expansion led to cracks and

joints A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...

in Earth's interior, that could fill with

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

. This was followed by a cooling phase, where the magma would freeze and become solid rock again, causing Earth to shrink.

Mass addition

In 1888 Ivan Osipovich Yarkovsky suggested that some sort of aether is absorbed within Earth and transformed into new chemical elements, forcing the celestial bodies to expand. This was connected with his mechanical explanation of gravitation. Also the theses of Ott Christoph Hilgenberg (1933, 1974) and

Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''

After initially supporting continental drift, the late Australian geologist S. Warren Carey advocated expansion from the 1950s (before the development of plate tectonics provided the generally accepted explanation of the movement of continents) to his death, demonstrating that subduction and other events could not balance the sea-floor spreading at

oceanic ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diverg ...

s, and piling yet unresolved paradoxes that continue to plague plate tectonics. Starting in 1956, he proposed some sort of mass increase in the planets and said that a final solution to the problem is only possible in a

cosmological Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...

perspective in connection with the expansion of the universe.

Bruce Heezen Bruce Charles Heezen (; April 11, 1924 – June 21, 1977) was an American geologist. He worked with oceanographic cartographer Marie Tharp at Columbia University to map the Mid-Atlantic Ridge in the 1950s. Biography Heezen was born in Vinton, Io ...

initially interpreted his work on the mid-Atlantic ridge as supporting S. Warren Carey's Expanding Earth Theory, but later withdrew his support, finally convinced by the data and analysis of his assistant,

Marie Tharp Marie Tharp (July 30, 1920 – August 23, 2006) was an American geologist and oceanographic cartographer. In the 1950s, she collaborated with geologist Bruce Heezen to produce the first scientific map of the Atlantic Ocean floor. Her cartograp ...

. The remaining proponents after the 1970s, like the Australian geologist James Maxlow, are mainly inspired by Carey's ideas. To date no scientific mechanism of action has been proposed for this addition of new mass. This is a big obstacle for acceptance of the theory by other geologists. It is a well known fact that the earth is constantly acquiring mass through accumulation of rocks and dust from space, as are all other planetary bodies in our system. According to NASA, "Every day about 100 tons of meteoroids -- fragments of dust and gravel and sometimes even big rocks – enter the Earth's atmosphere." The majority of this debris burns up in the atmosphere and lands as dust. Such accretion, however, is only a minuscule fraction of the mass increase required by the growing earth hypothesis.

Decrease of the gravitational constant

Paul Dirac Paul Adrien Maurice Dirac (; 8 August 1902 – 20 October 1984) was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century. He was the Lucasian Professor of Mathematics at the Univer ...

suggested in 1938 that the universal gravitational constant had ''decreased'' in the billions of years of its existence. This led German physicist

Pascual Jordan Ernst Pascual Jordan (; 18 October 1902 – 31 July 1980) was a German theoretical and mathematical physicist who made significant contributions to quantum mechanics and quantum field theory. He contributed much to the mathematical form of matri ...

to a modification of

general relativity General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...

and to propose in 1964 that all planets slowly expand. This explanation is within the framework of physics considered as a viable hypothesis. Measurements of a possible variation of the gravitational constant showed an upper limit for a relative change of per year, excluding Jordan's idea.

Formation from a gas giant

According to the hypothesis of J. Marvin Herndon (2005, 2013) the Earth originated in its protoplanetary stage from a

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...

-like

gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...

. During development phases of the young

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

, which resembled to those of a

T Tauri star T Tauri stars (TTS) are a class of variable stars that are less than about ten million years old. This class is named after the prototype, T Tauri, a young star in the Taurus star-forming region. They are found near molecular clouds and ide ...

, the dense atmosphere of the gas giant was stripped off by infrared eruptions from the sun. The remnant was a rocky planet. Due to the loss of pressure from its atmosphere would have begun a progressive decompression. Herndon regards the energy released due to the lack of compression as a primary energy source for geotectonic activity, to which some energy from radioactive decomposition processes was added. He calls the resulting changes in the course of Earth's history by the name of his theory ''Whole-Earth Decompression Dynamics''. He considered the

seafloor spreading Seafloor spreading or Seafloor spread is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener a ...

at divergent plate boundaries as an effect of it. In his opinion mantle convection used as concept in the theory of

is physically impossible. His theory includes the effect of

solar wind The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...

(

geomagnetic storms A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that d ...

) as cause for the reversals of the Earth magnetic field. The question of mass increase is not addressed.

Main arguments against Earth expansion

The hypothesis had never developed a plausible and verifiable mechanism of action. During the 1960s, the theory of

—initially based on the assumption that Earth's size remains constant, and relating the subduction zones to burying of lithosphere at a scale comparable to seafloor spreading—became the accepted explanation in the Earth Sciences. The scientific community finds that significant evidence contradicts the Expanding Earth theory, and that evidence used in support of it is better explained by plate tectonics: *Measurements with modern high-precision

geodetic Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...

techniques and modeling of the measurements by the horizontal motions of independent rigid plates at the surface of a globe of free radius, were proposed as evidence that Earth is not currently increasing in size to within a measurement accuracy of 0.2 mm per year. The lead author of the study stated "Our study provides an independent confirmation that the solid Earth is not getting larger at present, within current measurement uncertainties". * The motions of

tectonic plates Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...

and subduction zones measured by a large range of geological, geodetic and geophysical techniques supports plate tectonics.Fowler (1990), pp 281 & 320–327; Duff (1993), pp 609–613; Stanley (1999), pp 223–226 * Imaging of lithosphere fragments within the mantle supports lithosphere consumption by subduction. *

Paleomagnetic Paleomagnetism (or palaeomagnetismsee ), is the study of magnetic fields recorded in rocks, sediment, or archeological materials. Geophysicists who specialize in paleomagnetism are called ''paleomagnetists.'' Certain magnetic minerals in roc ...

data has been used to calculate that the radius of Earth 400 million years ago was 102 ± 2.8 percent of today's radius. *Examinations of data from the Paleozoic and Earth's moment of inertia suggest that there has been no significant change of Earth's radius in the last 620 million years.

Notes

Bibliography

* ; 1976: "The Expanding Earth", Developments in Geotectonics (10), Elsevier, ; digital edition 2013: ASIN B01E3II6VY. * ;1988: "Theories of the Earth and Universe: A History of Dogma in the Earth Sciences", Stanford University Press, . * ; 1993: '' Holmes' principles of physical geology'', Chapman & Hall (4th ed.), . * ; 1990: ''The Solid Earth, an introduction to Global Geophysics'', Cambridge University Press, . * ; 1999: ''Earth System History'', W.H. Freeman & Co, .

External links

* {{Commons-inline, Expanding Earth, Expanding Earth

Historical

* Ott Christoph Hilgenberg: * G. Scalera
Roberto Mantovani an Italian defender of the continental drift and planetary expansion
* Giancarlo Scalera
Variable Radius CartographyBirth and Perspectives of a New Experimental Discipline
* G. Scalera, Braun
Ott Christoph Hilgenberg in twentieth-century geophysics
* G. Scalera
Samuel Warren Carey – Commemorative memoir
* Andrew Alden

Contemporary

Database of Expansion Tectonic Scientists, living and deceased
Structure of the Earth Geophysics Geodynamics Obsolete geology theories