Geophysical global cooling
Encyclopedia
Before the concept of plate tectonics
, global cooling was a reference to a geophysical
theory by James Dwight Dana
, also referred to as the contracting earth theory. It suggested that the Earth
had been in a molten state, and features such as mountains formed as it cooled and shrank. As the interior of the Earth cooled and shrank, the rigid crust would have to shrink and crumple. The crumpling could produce features such as mountain ranges.
In the early 1900s, Professor Eduard Suess
used the theory to explain the 1908 Messina earthquake
, being of the opinion that the Earth's crust was gradually shrinking everywhere. He also predicted that eruptions would follow the earthquake and tsunami in Southern Italy. He attributed the earthquake to the sinking of the Earth's crust, in the zone of which the Aeolian Islands are the center. He declared that as the process of sinking went on, the Calabrian and Sicilian highlands on either side of the Straits of Messina would be submerged, only the highest peaks remaining above the sea. The strait, he said, would thereby be greatly widened.
Similarly, Professor Robert T. Hill
explained at that time that "the rocks are being folded, fractured and otherwise broken or deformed by the great shrinking and settling of the earth's crust as a whole. The contraction of the earth's sphere is the physical shrinkage of age that is measured in aeons instead of years. The prehistoric convulsions of the earth before man inhabited this planet were terrific, almost inconceivable." There "was no doubt that earthquakes are diminishing." The displacement of the 1906 San Francisco earthquake
was only a few feet, while prehistoric earthquakes made fissures and slides of 20,000 feet.
The Pacific Ring of Fire
had been noticed, as well as a second earthquake belt which went through:
. After resumption of Lunar exploration in the 1990s, it was discovered there are scarps across the globe which are caused by the contraction due to cooling of the Moon.
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
, global cooling was a reference to a geophysical
Geophysics
Geophysics is the physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. The term geophysics sometimes refers only to the geological applications: Earth's shape; its gravitational and magnetic fields; its internal structure and...
theory by James Dwight Dana
James Dwight Dana
James Dwight Dana was an American geologist, mineralogist and zoologist. He made pioneering studies of mountain-building, volcanic activity, and the origin and structure of continents and oceans around the world.-Early life and career:...
, also referred to as the contracting earth theory. It suggested that 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...
had been in a molten state, and features such as mountains formed as it cooled and shrank. As the interior of the Earth cooled and shrank, the rigid crust would have to shrink and crumple. The crumpling could produce features such as mountain ranges.
Application
The Earth was compared to a cooling ball of iron, or a steam boiler with shifting boiler plates. By the early 1900s, it was known that temperature increased with increasing depth. With the thickness of the crust, the "boiler plates", being estimated at ten to fifty miles, the downward pressure would be hundreds of thousands of pounds per square inch. Although groundwater was expected to turn to steam at a great depth, usually the downward pressure would contain any steam. Steam's effect upon molten rock was suspected of being a cause of volcanoes and earthquakes, as it had been noticed that most volcanoes are near water. It was not clear whether the molten rock from volcanoes had its origin in the molten rock under the crust, or if increased heat due to pressure under mountains caused the rock to melt. One of the reasons for volcanoes was as a way in which "the contracting earth disposes of the matter it can no longer contain." A relationship between earthquakes and volcanoes had been noted, although the causes were not known. Fault lines and earthquakes tended to happen along the boundaries of the shifting "boiler plates", but the folding of mountains indicated that sometimes the plates buckled.In the early 1900s, Professor Eduard Suess
Eduard Suess
Eduard Suess was a geologist who was an expert on the geography of the Alps. He is responsible for hypothesising two major former geographical features, the supercontinent Gondwana and the Tethys Ocean.Born in London to a Jewish Saxon merchant, when he was three his family relocated toPrague,...
used the theory to explain the 1908 Messina earthquake
1908 Messina earthquake
The 1908 Messina earthquake and tsunami took some 100,000–200,000 lives on December 28, 1908 in Sicily and Calabria, southern Italy.-Quake:On December 28, 1908 from about 05:20 to 05:21 an earthquake of 7.2 on the moment magnitude scale occurred centered on the of city Messina, in Sicily. Reggio...
, being of the opinion that the Earth's crust was gradually shrinking everywhere. He also predicted that eruptions would follow the earthquake and tsunami in Southern Italy. He attributed the earthquake to the sinking of the Earth's crust, in the zone of which the Aeolian Islands are the center. He declared that as the process of sinking went on, the Calabrian and Sicilian highlands on either side of the Straits of Messina would be submerged, only the highest peaks remaining above the sea. The strait, he said, would thereby be greatly widened.
Similarly, Professor Robert T. Hill
Robert T. Hill
Robert Thomas Hill was a significant figure in the development of American geology during the late nineteenth century and in the early part of the twentieth century...
explained at that time that "the rocks are being folded, fractured and otherwise broken or deformed by the great shrinking and settling of the earth's crust as a whole. The contraction of the earth's sphere is the physical shrinkage of age that is measured in aeons instead of years. The prehistoric convulsions of the earth before man inhabited this planet were terrific, almost inconceivable." There "was no doubt that earthquakes are diminishing." The displacement of the 1906 San Francisco earthquake
1906 San Francisco earthquake
The San Francisco earthquake of 1906 was a major earthquake that struck San Francisco, California, and the coast of Northern California at 5:12 a.m. on Wednesday, April 18, 1906. The most widely accepted estimate for the magnitude of the earthquake is a moment magnitude of 7.9; however, other...
was only a few feet, while prehistoric earthquakes made fissures and slides of 20,000 feet.
The Pacific Ring of Fire
Pacific Ring of Fire
The Pacific Ring of Fire is an area where large numbers of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. In a horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements...
had been noticed, as well as a second earthquake belt which went through:
- the PhilippinesPhilippinesThe Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
- PanamaPanamaPanama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
- the CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
- SpainSpainSpain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
- the AlpsAlpsThe Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
- the HimalayasHimalayasThe Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
- Asia to JapanJapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
Objections
Some of the objections include:- Some large-scale features of the Earth are the result of extension rather than shortening.
- After radioactive decayRadioactive decayRadioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles . The emission is spontaneous, in that the atom decays without any physical interaction with another particle from outside the atom...
was discovered, it was realized it would release heat inside the planet. This undermines the cooling effect upon which the shrinking planet theory is based. - Identical fossils have been found thousands of kilometres apart, showing the planet was once a single continent which broke apart because of plate tectonicsPlate tectonicsPlate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
.
Current status
This theory is now disproven and considered obsolete. In contrast to Earth, however, global cooling remains the dominant explanation for scarp (cliff) features on the planet MercuryMercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
. After resumption of Lunar exploration in the 1990s, it was discovered there are scarps across the globe which are caused by the contraction due to cooling of the Moon.