contracting Earth hypothesis (17th century) Geology - …

But the Contracting Earth theory couldn't explain the irregular distribution of mountain ranges on earth and why there are regions with strong tectonic movements and earthquakes and "quiet" areas. According to this theory, such features and events should to be distributed randomly on the surface of a homogenous cooling and shrinking planet.

05/01/2012 · From the Contracting Earth to ..

The topic that we deleted concerned the short-lived hypothesis that the Earth might be expanding.

EARTH520 Contracting Earth Hypothesis - YouTube

Artists have been depicting Carboniferous swamps for more than a century, and the . That represents a key Carboniferous issue and perhaps why the period ended. That , and others like it, appeared in the fossil record about 300 mya, when oxygen levels were Earth’s highest ever, at somewhere between 25% and 35%. The almost universally accepted reason for that high oxygen level is that for the entire Carboniferous Period removed carbon dioxide from the atmosphere in vast amounts. Today, the estimate is that carbon dioxide fell from about 1,500 PPM at the beginning of the Carboniferous to 350 PPM by the end, which is lower than today’s value. That tandem effect of sequestering carbon and freeing oxygen not only may have led to huge arthropods and amphibians, but also intensified . The idea that high oxygen levels led to those giants was first proposed more than a century ago and dismissed, but has recently come back into favor. Flying insects have the highest metabolisms of all animals, but they do not have diaphragmatic lungs as mammals have, or air sac lungs as birds have, and although they may have some way of actively breathing by contracting their tracheas, it is not the bellows action of vertebrate lungs. The for early insect gigantism is that high oxygen, as well as a denser atmosphere (the nitrogen mass would not have fallen, so increased oxygen would have added to the atmosphere’s mass), would have enabled such leviathans to fly, and the other is that flying insects got a head start in the arms race and could grow large until predators that could catch them evolved. The late Permian had an even larger dragonfly, when oxygen levels had crashed back down. The evolution of flight is another area of great controversy, and insects accomplished it long before vertebrates did. The general idea is that flight structures evolved from those used for other purposes. For insects, wings appear to have evolved from aquatic “oars,” and gills became lungs. Reptiles did not develop flight until the Triassic, and .

contracting Earth hypothesis - oi - Oxford Index Home

When the beginning about 307 mya, Earth’s oxygen levels were at their highest ever. About 75% of Earth’s coal deposits were formed in the Carboniferous, with most of it laid down in the 25-million-year Pennsylvanian Epoch. There will never be a coal-forming period like that again on Earth, as organisms about 290 mya. Even if humans burned all fossil fuel deposits, carbon dioxide levels will never again reach the levels that preceded the Carboniferous, at many times today’s concentrations.

Imagine running a film ofcosmic expansion backwards to the Big Bang--inother words, a contracting universe instead of an expanding universe.
The contracting Earth hypothesis was further refined by introducing isostasy

contracting Earth hypothesis; contracting Earth ..

Polar forests reappeared in the Eocene after the , and the Eocene’s was the Cenozoic’s warmest time and . Not only did alligators live near the North Pole, but the continents and oceans hosted an abundance and diversity of life that Earth may have not seen before or since. That ten million year period ended as Earth began cooling off and headed toward the current ice age, and it has been called the original Paradise Lost. One way that methane has been implicated in those hot times is that leaves have , which regulate the air they take in to obtain carbon dioxide and oxygen, needed for photosynthesis and respiration. Plants also lose water vapor through their stomata, so balancing gas input needs against water losses are key stomata functions, and it is thought that in periods of high carbon dioxide concentration, . Scientists can count stomata density in fossil leaves, which led some scientists to conclude that carbon dioxide levels were not high enough to produce the PETM, so that produced the PETM and , and the controversy and research continues.

The topic that we deleted concerned the short-lived hypothesis that the Earth ..

Elliott's inclusion of the Contracting Diagonal

In the early 19th century another hypothesis was proposed to explain the shape of Earth: the Contracting Earth theory formulated by the American geologist James Dwigth Dana explained mountains and continents as products of a cooling and subsequently shrinking earth. Like an old and dry apple the shrinking surface of earth would develop fissures (basins) and wrinkles (mountains).

he was dismayed to find that it predicted either an expanding or contracting universe ..

The Science Behind Discworld's Flat Earth on the Back …

Peter Ward led an effort to catalog the fossil record before and after Romer’s Gap, which found a dramatic that did not resume until about 340-330 mya. Romer’s Gap seems to have coincided with low-oxygen levels of the late Devonian and early Carboniferous. If coincided with a halt in colonization, just as the adaptation to breathing air was beginning, the obvious implication is that low oxygen levels hampered early land animals. Not just the lung had to evolve for the up-and-coming amphibians, but the entire chest cavity had to evolve to expand and contract while also allowing for a new mode of locomotion. When amphibians and splay-footed reptiles run, they cannot breathe, as their mechanics of locomotion prevent running and breathing at the same time. Even walking and breathing is generally difficult. This means that they cannot perform any endurance locomotion but have to move in short spurts. This is why today’s predatory amphibians and reptiles are ambush predators. They can only move in short bursts, and then have to stop, breathe, and recover their oxygen deficit. In short, they have no stamina. This limitation is called . The below image shows the evolutionary adaptations that led to overcoming Carrier's Constraint. Dinosaurs overcame it first, and it probably was related to their dominance and the extinction or marginalization of their competitors. (Source: Wikimedia Commons)