what type of information do scientist use to determine the approximate age of the earth?
Accept a await at a world or a map of the world and you may exist impressed by what yous see. Towering mountains, deep oceans, vast continents, and sprawling glaciers—they make Earth what it is today. Even more impressive, by some people'southward standards, is the age of World. Scientists have calculated the age of our planet to be approximately 4.5 billion years. But how did scientists determine that age? The answer is complicated: It involves everything from observation to complicated mathematics to agreement the elements that make up our planet.
In the 1800s, as scientists sought to determine the historic period of the planet, they made a few missteps. In 1862, a famous Irish gaelic physicist and mathematician, Lord Kelvin, estimated that Earth was between 20-1000000 and 400-million years old. While that is an enormous span of fourth dimension, even an historic period of 400 meg years would make the planet quite young in relation to the residuum of the universe. Lord Kelvin based his conclusion on a calculation of how long information technology would have taken Earth to absurd if it had begun every bit a molten mass. While his estimate was wrong by a meaning margin, his technique of cartoon conclusions based on observations and calculations was an accurate scientific method.
Scientists besides tried to use relative dating techniques to make up one's mind the age of the planet. Stratigraphy compares the configuration of layers of stone or sediment in order to determine how old each layer is in relation to 1 some other. This technique can reveal which layers are older or which events happened before others if the layers of sediment have remained in sequential order. Layers tin berearranged, bent, or comprise inconsistencies. However, stratigraphy yields no verbal age for those layers or events. Nonetheless, fifty-fifty though this technique did not give scientists the precise number they were looking for, it did advise that Earth was well-nigh likely billions of years quondam, and not just millions every bit was previously thought.
As advances in chemistry, geology, and physics continued, scientists constitute a method by which the absolute age—an actual number of years—of a rock or mineral sample could be determined. This method is called radiometric dating, and it involves the decay, or breakdown, of radioactive elements. Using radiometric dating techniques, information technology became possible to determine the actual age of a sample.
Radiometric dating requires an understanding of isotopes. Isotopes are variations of an chemical element differentiated by the number of neutrons in their nuclei. The isotopes of unstable radioactive elements—known as parent isotopes—somewhen disuse into other, more stable elements—known as girl isotopes—in a predictable manner, and in a precise amount of time called a half-life. The half-life of an chemical element is the amount of fourth dimension required for exactly half of a quantity of that chemical element to decay. The age of a sample tin can be adamant based on the ratio of parent to daughter isotopes within the sample.
One problem with this approach to dating rocks and minerals on Earth is the presence of the rock wheel. During the rock cycle, rocks are constantly changing between forms, going back and forth from igneous to metamorphic to sedimentary. Sometime rocks may even be destroyed equally they slide dorsum into Globe's drapery, to be replaced by newer rocks formed by solidified lava. This makes finding an exact age for Earth difficult, because the original rocks that formed on the planet at the earliest stages of its creation are no longer here. The oldest rocks that have been found are about 3.8-billion years old, though some tiny minerals have been dated at 4.ii billion years.
To get around the difficulty presented by the rock cycle, scientists have looked elsewhere in the solar system for fifty-fifty older rock samples. They accept examined rocks from the moon and from meteorites, neither of which have been altered past the rock cycle. The aforementioned techniques of radiometric dating have been used on those rocks.All the information from Earth and beyond has led to the estimated age of 4.5 billion years for our planet.
The age of rocks is determined past radiometric dating, which looks at the proportion of two unlike isotopes in a sample. Radioactive isotopes pause downward in a predictable amount of time, enabling geologists to determine the age of a sample using equipment like this thermal ionization mass spectrometer.
Photograph by Radiogenic
absolute dating
Substantive
determining the absolute historic period of something, usually through isotope analysis; yields an actual number.
extraterrestrial
Adjective
located or formed outside Earth'southward atmosphere.
half-life
Substantive
fourth dimension required for one-half of something to decay or exist eliminated.
Noun
rock formed by the cooling of magma or lava.
isotope
Noun
cantlet with an unbalanced number of neutrons in its nucleus, giving it a unlike atomic weight than other atoms of the same element.
Substantive
middle layer of the Globe, made of more often than not solid rock.
metamorphic rock
Noun
rock that has transformed its chemical qualities from igneous or sedimentary.
Noun
type of rock that has crashed into Earth from exterior the atmosphere.
neutron
Noun
particle in an atom having no electrical accuse.
nucleus
Noun
positively charged central region of an atom, containing protons and neutrons.
radioactive
Adjective
having unstable atomic nuclei and emitting subatomic particles and radiation.
radioactive decay
Noun
transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. Too called radioactivity.
radiometric dating
Substantive
method of dating material such every bit rocks that compares the amount of a naturally occuring isotope of an atom and its decay rates. Also chosen radioactive dating.
relative dating
Noun
estimating the relative age of something, usually by comparison rock and soil layers; does not give an verbal number.
Noun
processes that explain the relationship between the three rock types: igneous, sedimentary, and metamorphic. Any rock type can get any other.
Noun
rock formed from fragments of other rocks or the remains of plants or animals.
solar system
Noun
the sunday and the planets, asteroids, comets, and other bodies that orbit around it.
thompsonthersim1982.blogspot.com
Source: https://www.nationalgeographic.org/article/how-did-scientists-calculate-age-earth/
0 Response to "what type of information do scientist use to determine the approximate age of the earth?"
Postar um comentário