Radiometric dating - Wikipedia
Astronomers have, however, been able to estimate the age of the Solar System via radiometric dating. Usually we think of using radiometric. This age has been determined with the radioactive dating technique. Dating meteorites thus allows us to give a lower age to the Solar System (4,56 billion. We can then use radioactive age dating in order to date the ages of the all of the objects in the Solar System formed very quickly about billion years ago.
Uranium—lead dating method[ edit ] Main article: Uranium—lead dating A concordia diagram as used in uranium—lead datingwith data from the Pfunze BeltZimbabwe. This scheme has been refined to the point that the error margin in dates of rocks can be as low as less than two million years in two-and-a-half billion years.
Zircon has a very high closure temperature, is resistant to mechanical weathering and is very chemically inert. Zircon also forms multiple crystal layers during metamorphic events, which each may record an isotopic age of the event. This can be seen in the concordia diagram, where the samples plot along an errorchron straight line which intersects the concordia curve at the age of the sample.
Samarium—neodymium dating method[ edit ] Main article: Samarium—neodymium dating This involves the alpha decay of Sm to Nd with a half-life of 1. Accuracy levels of within twenty million years in ages of two-and-a-half billion years are achievable. Potassium—argon dating This involves electron capture or positron decay of potassium to argon Potassium has a half-life of 1.
Rubidium—strontium dating method[ edit ] Main article: Rubidium—strontium dating This is based on the beta decay of rubidium to strontiumwith a half-life of 50 billion years. This scheme is used to date old igneous and metamorphic rocksand has also been used to date lunar samples.
Closure temperatures are so high that they are not a concern.
Rubidium-strontium dating is not as precise as the uranium-lead method, with errors of 30 to 50 million years for a 3-billion-year-old sample. Uranium—thorium dating method[ edit ] Main article: Uranium—thorium dating A relatively short-range dating technique is based on the decay of uranium into thorium, a substance with a half-life of about 80, years. It is accompanied by a sister process, in which uranium decays into protactinium, which has a half-life of 32, years.
While uranium is water-soluble, thorium and protactinium are not, and so they are selectively precipitated into ocean-floor sedimentsfrom which their ratios are measured.How Do You Date a Rock?
The scheme has a range of several hundred thousand years. A related method is ionium—thorium datingwhich measures the ratio of ionium thorium to thorium in ocean sediment. Radiocarbon dating method[ edit ] Main article: Carbon is a radioactive isotope of carbon, with a half-life of 5, years,   which is very short compared with the above isotopes and decays into nitrogen.
- How are the ages of the Earth and universe calculated?
- FAQ - Radioactive Age-Dating
- Dating the Solar System?
Carbon, though, is continuously created through collisions of neutrons generated by cosmic rays with nitrogen in the upper atmosphere and thus remains at a near-constant level on Earth. The carbon ends up as a trace component in atmospheric carbon dioxide CO2. A carbon-based life form acquires carbon during its lifetime.
Plants acquire it through photosynthesisand animals acquire it from consumption of plants and other animals. When an organism dies, it ceases to take in new carbon, and the existing isotope decays with a characteristic half-life years.
The proportion of carbon left when the remains of the organism are examined provides an indication of the time elapsed since its death.
This makes carbon an ideal dating method to date the age of bones or the remains of an organism. The carbon dating limit lies around 58, to 62, years. However, local eruptions of volcanoes or other events that give off large amounts of carbon dioxide can reduce local concentrations of carbon and give inaccurate dates.
The releases of carbon dioxide into the biosphere as a consequence of industrialization have also depressed the proportion of carbon by a few percent; conversely, the amount of carbon was increased by above-ground nuclear bomb tests that were conducted into the early s. Also, an increase in the solar wind or the Earth's magnetic field above the current value would depress the amount of carbon created in the atmosphere.
Radioactive Dating and the Age of the Solar System
Fission track dating method[ edit ] Main article: The material making up these rocks has been part of the Earth for all 4. The oldest rocks in the Solar System -- the ones which have not been melted since they were first formed -- are the meteorites which fall to Earth from interplanetary space. The meteorites are pieces of the asteroids -- leftover fragments of planetesimals from the era of the formation of the planets.
They solidified early in the history of the Solar System and have not melted since.
Jupiter stirred up the motions of the nearby planetesimals and prevented them from accumulating into a planet. These stirred planetesimals collided at high speed and fragmented.
FAQ - Radioactive Age-Dating | Planetary Science Institute
They were unable to stick together and accumulate to form a large planet. These leftover planetesimal pieces now form the asteroid belt. In this way, multiple trees can be used to build a master chronology for a forested region. European oak trees have been used to build a 12,year chronology. Each year, snowfall varies throughout the seasons and an annual layer is formed. Like the tree rings, this method can be verified by comparison to historical records for weather, as well as to records of volcanic eruptions around the globe that left thin dust layers on the glaciers.
Scientists have drilled ice cores deep into glaciers and found ice that isyears old in Greenland2 andyears old in Antarctica. The Earth must be at leastyears old. Age of the Earth and solar system from radiometric dating In your high school science classroom, you may have seen a large poster of the periodic table hanging on the wall. The periodic table shows the types of atoms that make up the world around us. An element in the periodic table can come in different flavors called isotopes.
For example, Potassium is unstable and decays into Argon