The history of great scrolls of big scientists deployed over the theme "How old is the earth?"

ByBeth Scupham

Even a learned person who can answer "4.6 billion years" when asked "What is the age of the earth?" May not know what kind of history it had before arriving at the answer. In the age controversy of the Earth, there was a history of massive hot debate when numerous scientists who entered the era entered.

Science News
http://www.scientificamerican.com/

Ancient Greek philosopherAristotleI thought that "the earth is permanent." I thought that Earth exists at the center of the worldCosmologyThen, it was thought that the earth was in the center of the universe forever, even if it dates back the time, without the moment when the earth was born.

Aristotle (384 BC - 322 BC).


About 2000 years since Aristotle's era, in 1654, Irish bishop James Asher calculated the time to creation of the earth based on the biblical account and led the conclusion that the earth was born in 4004 BC (Usher's chronicle).


From the time Asher's chronology was announced, scientists will participate in the age controversy of the earth. It was an anatomist / geologist in Denmark in the 1660sNicolaus StenoDiscovered that the shapes of shark teeth and fossils are similar, it is presumed that the rock formations including fossils were deposited at the bottom of the ocean, and the older the sedimentary layer goes down the "Law of stratum accumulationWe advocate this theory and have formulated the formula to estimate the history of the earth from sediments of the strata. "Hook's lawFamous forRobert HookI also suggested that fossil records like the stenos would form the basis of the chronicle.

Nicolaus Steno is also famous for discovering the parotid duct (stenotube).


In the 18th centuryJames HuttonHe advocated the sense of earth that the process of geology is believed to be occurring by the same force both in the past and now, "the key to solve the past now" is the key to solving the earth's feelings, "Since no trace of the beginning can be found, I can not foresee it. " Following this,Charles RyelArgues that the process of forming a geological structure and being eroded and reformed occurs at a constant pace and concludes that the age of the earth is over a few hundred million years. Hatton and Lyer's position, then "A quarterly ideaIt will be widely known as

Various theories were spoken for the birth of the earth, various ages were asserted and the discussion was in disarray, finally armed with stone stones to make the age of the earth someday between 40 million years ago and 20 million years ago The treasure of the physics society Britain is proud ofWilliam Thomson(Later Sir Kelvin). Thomson denies that Lyel's argument is not theoretical and intensely attacks the theory of uniformity. Many of those physicists represented by Thomson at that time thought that "Although the Earth had melted for the first time, it solidified from the surface by cooling, but the core (center) is still melting". However"Second law of thermodynamicsA phenomenal genius physicist who invented the Earth measured the time change of the temperature distribution of the earth and used Fourier's theory of heat conduction to estimate the age of the earth to be between 40 million years ago and 20 million years ago .

William Thomson, who was later grouped in aristocracy by scientific achievement and "Lord Kelvin". As a unit of absolute temperature "Kelvin"Was attached to him.


Thomson 's claim shocks the geological society that considered the origin of the earth as their specialty area. They have no strong theory to object to physicists who have stepped into their territory, and additionally Thomson's calculation was an impregnable fortress based on precise physics theory. In addition, Thomson's estimate was shocking not only to geologists but also to biologists. at that time,"Theory of evolutionI recitedCharles DarwinFor Thompson's 40 million years it was too short a time for complex creatures to evolve.

It is pointed out by geologist Thomas · Huxleyley that Thomson's initial calculation had a serious mistake that radiation heat from the sun was not taken into account. But in the fight against this geologist, German physicistHermann HelmholtzAnd American astronomersSimon NewcombIt is a guided shooting, leading to the conclusion that the upper limit of the age of the earth is 100 million years.

After that, geologists will respond to Thomson with the formation rate of the strata by river sediment and the contribution of salt concentration supplied by the river to the ocean, but gradually synchronized with Thomson's "Earth 100 million years old" The number of geologists increasing, the Geological Society will fall to the army gate of the Physical Society.

But just before the 20th centuryHenri Becquerel,Pierre Curie/Mari CurieMr. and Mrs.radioactivity"Is discovered, from which the age measurement method of the earth by the analysis of the radioactive element quantity is devised. This includes uranium and radiumHalf lifeThe absolute age of the rock is inversely calculated from the radioactive decay amount of the rock containing the long radioactive material. BritishArthur HolmesEstimates the amount of radioactive decay of uranium-containing rocks and calculates backwards from it to make the birth of the earth 1.6 billion years ago. Incidentally, Holmes is a geologist, and it is a causal result that the method used by geologists who reversed the theory of 100 million years of the Physics Society is physics.

after that,IsotopeThe discovery of Holmes increased the accuracy of the theory, in 1955Claire PattersonBut,Canyon Diablo MeteoriteThe age of the earth was measured indirectly from there. This is based on the idea that the meteorite is "a residue of solar system formation" and therefore the age of the earth can be clarified by measuring the age of the meteorite. Patterson's calculation result is4.55 billion years, And this figure is regarded as the age of the Earth that is still unchanged.


In this way, the age controversy of the Earth involving the great scientists representing that era is considered to have ended for the moment. However, no one knows whether the day will come when a genius that will create a new theory to rekindle this major controversy will appear in the future.