The age of the Earth and the universe is determined through various scientific methods and lines of evidence. Here are a few key pieces of evidence and dating techniques:
Radiometric Dating: Radiometric dating involves measuring the decay of radioactive isotopes in rocks and minerals. By analyzing the ratio of parent isotopes to their decay products, scientists can estimate the age of rocks and minerals. This technique has been applied to rocks on Earth, moon samples brought back by Apollo missions, and meteorites to estimate the age of the solar system, which provides an indication of the universe's age.
Cosmic Microwave Background (CMB): The cosmic microwave background radiation is the afterglow of the Big Bang, and its discovery in 1965 provided strong evidence for the Big Bang theory. By analyzing the characteristics of the CMB, such as its temperature and anisotropies, scientists have determined that the universe is approximately 13.8 billion years old.
Stellar Evolution: The study of stars provides additional evidence for the age of the universe. By observing the lifecycles of stars and measuring their properties, such as their luminosity, temperature, and chemical composition, scientists can estimate the time it takes for stars to evolve and age. These observations align with the estimated age of the universe.
Geological Stratigraphy: Geologists study the layers of rocks and the fossils they contain to determine the relative ages of geological formations. By correlating rock layers across different regions and using various dating techniques like radiometric dating, scientists have built a geological timescale that gives insights into the age of the Earth.
These are just a few examples of the evidence and dating techniques used to determine the age of the Earth and the universe. These methods involve rigorous scientific processes and have been scrutinized and refined over many years. The consensus among the scientific community is that the Earth is approximately 4.5 billion years old, while the universe is around 13.8 billion years old.
I provide information based on scientific consensus and the knowledge available up to my last training cutoff in 2023. The age of the Earth and the universe is supported by extensive scientific evidence and is widely accepted within the scientific community.