Age of the Earth

formation of the EarthEarthage of EarthEarth's ageabout 4.54 billion years agoAntiquityOld Earth4.5 billion4.5 billion years old4.54 billion year
The age of the Earth is estimated to be 4.54 ± 0.05 billion years (4.54 × 10 9 years ± 1%).wikipedia
261 Related Articles

Moon

lunarthe MoonLuna
This dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.
The Moon is thought to have formed about 4.51 billion years ago, not long after Earth.

Radiometric dating

radiometrically dateddatedradiometric
This dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.
The use of radiometric dating was first published in 1907 by Bertram Boltwood and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of the Earth itself, and can also be used to date a wide range of natural and man-made materials.

Earth

Earth's surfaceterrestrialworld
His calculations did not account for heat produced via radioactive decay (a then unknown process) or, more significantly, convection inside the Earth, which allows the temperature in the upper mantle to remain high much longer, maintaining a high thermal gradient in the crust much longer.
According to radiometric dating and other sources of evidence, Earth formed over 4.5 billion years ago.

Uranium–lead dating

uranium-lead datinguranium-leadU-Pb dating
Following the development of radiometric age-dating in the early 20th century, measurements of lead in uranium-rich minerals showed that some were in excess of a billion years old.
Clair Cameron Patterson, an American geochemist who pioneered studies of uranium–lead radiometric dating methods, used it to obtain one of the earliest estimates of the age of the Earth.

Hermann von Helmholtz

HelmholtzHermann HelmholtzHermann Ludwig Ferdinand von Helmholtz
The physicist Hermann von Helmholtz (in 1856) and astronomer Simon Newcomb (in 1892) contributed their own calculations of 22 and 18 million years respectively to the debate: they independently calculated the amount of time it would take for the Sun to condense down to its current diameter and brightness from the nebula of gas and dust from which it was born.
Trained primarily in physiology, Helmholtz wrote on many other topics, ranging from theoretical physics, to the age of the Earth, to the origin of the Solar System.

Uranium

UU 2 U(VI)
Typical radioactive end products are argon from decay of potassium-40, and lead from decay of uranium and thorium.
The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth.

Thorium

Ththorium-232thoriated
Typical radioactive end products are argon from decay of potassium-40, and lead from decay of uranium and thorium.
232 Th is one of the three nuclides beyond bismuth (the other two being 235 U and 238 U) that have half-lives measured in billions of years; its half-life is 14.05 billion years, about three times the age of the earth, and slightly longer than the age of the universe.

Georges-Louis Leclerc, Comte de Buffon

BuffonComte de BuffonLeclerc de Buffon
In 1779 the Comte du Buffon tried to obtain a value for the age of Earth using an experiment: He created a small globe that resembled Earth in composition and then measured its rate of cooling.
He also suggested that the earth originated much earlier than 4004 BC, the date determined by Archbishop James Ussher.

James Hutton

HuttonHutton, JamesDr. James Hutton
In 1830, geologist Charles Lyell, developing ideas found in James Hutton's works, popularized the concept that the features of Earth were in perpetual change, eroding and reforming continuously, and the rate of this change was roughly constant.
Rather than accepting that the earth was no more than a few thousand years old, he maintained that the Earth must be much older, with a history extending indefinitely into the distant past.

Kelvin–Helmholtz mechanism

gravitational contractionKelvin–Helmholtz heatingKelvin–Helmholtz luminosity
However, they assumed that the Sun was only glowing from the heat of its gravitational contraction.
However, it soon was recognized by Sir Arthur Eddington and others that the total amount of energy available through this mechanism only allowed the Sun to shine for millions of years rather than the billions of years that the geological and biological evidence suggested for the age of the Earth.

Evolution

evolvedtheory of evolutionevolutionary
In Darwin's theory of evolution, the process of random heritable variation with cumulative selection requires great durations of time.
The Earth is about 4.54 billion years old.

William Thomson, 1st Baron Kelvin

Lord KelvinWilliam ThomsonWilliam Thomson, Lord Kelvin
In 1862, the physicist William Thomson, 1st Baron Kelvin published calculations that fixed the age of Earth at between 20 million and 400 million years.
Kelvin estimated of the age of the Earth.

Lead–lead dating

lead-lead dating 206 Pb/ 204 PbPb-Pb
An age of 4.55 ± 0.07 billion years, very close to today's accepted age, was determined by Clair Cameron Patterson using uranium-lead isotope dating (specifically lead-lead dating) on several meteorites including the Canyon Diablo meteorite and published in 1956.
For most dating requirements it has been superseded by uranium–lead dating (U–Pb dating), but in certain specialized situations (such as dating meteorites and the age of the Earth) it is more important than U–Pb dating.

Radium

Raradium-226 226 Ra
After Henri Becquerel's initial discovery in 1896, Marie and Pierre Curie discovered the radioactive elements polonium and radium in 1898; and in 1903, Pierre Curie and Albert Laborde announced that radium produces enough heat to melt its own weight in ice in less than an hour.
All isotopes of radium have half-lives much shorter than the age of the Earth, so that any primordial radium would have decayed long ago.

Clair Cameron Patterson

Clair PattersonClair C. PattersonC. C. Patterson
An age of 4.55 ± 0.07 billion years, very close to today's accepted age, was determined by Clair Cameron Patterson using uranium-lead isotope dating (specifically lead-lead dating) on several meteorites including the Canyon Diablo meteorite and published in 1956.
By using lead isotopic data from the Canyon Diablo meteorite, he calculated an age for the Earth of 4.55 billion years, which was a figure far more accurate than those that existed at the time, and one that has remained largely unchanged since 1956.

Canyon Diablo (meteorite)

Canyon Diablo meteoriteCanyon DiabloCanyon Diablo Troilite
An age of 4.55 ± 0.07 billion years, very close to today's accepted age, was determined by Clair Cameron Patterson using uranium-lead isotope dating (specifically lead-lead dating) on several meteorites including the Canyon Diablo meteorite and published in 1956.
The result permitted a refinement of the estimate of the age of the Earth to 4.550 billion years (± 70 million years).

Arthur Holmes

Holmes, ArthurProfessor Arthur Holmes
However, Strutt's student Arthur Holmes became interested in radiometric dating and continued to work on it after everyone else had given up.
He estimated the oldest Archean rocks to be 1,600 Ma, but did not speculate about the Earth's age.

Plate tectonics

tectonic platesplate tectonictectonic
Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation.
The discovery of radioactivity and its associated heating properties in 1895 prompted a re-examination of the apparent age of the Earth.

Bertram Boltwood

BoltwoodBertram B. BoltwoodBoltwood family
The pioneers of radioactivity were chemist Bertram B. Boltwood and the energetic Rutherford.
More recently, older mineral deposits have been dated to about 4.4 billion years old, close to the best estimate of the age of earth.

Age of the universe

13.8 billion years ago13.8 billion yearsage
In the 18th century, the concept that the age of the Earth was millions, if not billions, of years began to appear.

1,000,000,000

billionbnmilliard
The age of the Earth is estimated to be 4.54 ± 0.05 billion years (4.54 × 10 9 years ± 1%).

Accretion (astrophysics)

accretionaccretingaccreted
This age may represent the age of the Earth's accretion, of core formation, or of the material from which the Earth formed.

Meteorite

meteoritesmeteoriticmeteoric
This dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.