Later, Kelvin's calculations used Earth's temperature change with depth, thermal properties of rocks, and a planetary body that started as a molten mass, to produce ages in the range of 50-100 my.
The timing and duration of their formation remains obscure.My colleagues, Yuri Amelin (Royal Ontario Museum), Ian Hutcheon (Lawrence Livermore National Laboratory), Alexander Ulyanov (Moscow State University), and I set out to resolve these unknowns by determining the absolute formation ages of CAIs and chondrules using lead isotopic analyses. (Kingsborough College-CUNY), chondrules and CAIs were heated by shock waves that originated in the asteroid belt region.Answer 2: Yes, radiometric dating is a very accurate way to date the Earth.We know it is accurate because radiometric dating is based on the radioactive decay of unstable isotopes.This combined X-ray elemental map shows Mg (red), Ca (green) and Al (blue) of the CR carbonaceous chondrite PCA 91082. Rocks like these preserve a record of the processes and timing of events in the solar nebula. This drawing depicts some of the processes that might have operated in the nebular disk surrounding the young Sun.
There are two mechanisms proposed for CAI and chondrule formation: shock waves and jet flows. It shows the jet flow model of CAI and chondrule formation.
The discovery of radioactivity was that the occurrence of some isotopes is unstable, such that a new element is formed spontaneously.
Of the two Rb isotopes, 87/37 Rb is unstable and it changes to the element strontium (87/38 Sr) by the conversion of a neutron into a proton and an electron.
hondritic meteorites (chondrites), the oldest rocks in our solar system, provide a significant record of the processes that transformed a disk of gas and dust into a collection of planets, moons, asteroids, and comets.
They are considered to be the building blocks of the inner planets, Mercury, Venus, Earth, and Mars.
Chondrites are aggregates of three major components: refractory Ca-Al-rich inclusions (CAIs), less refractory ferromagnesian silicate spherules called chondrules, and a fine-grained matrix.