Which allowed scientists to determine that Earth was at least 4.3 billion years old? (1 point)
• the electrical conductivity of uranium ions
O chemical reactivity of zircon ions
• the radioactive decay of uranium to lead
O magnetic field surrounding zircon
• the radioactive decay of uranium to lead
The answer is: The radioactive decay of uranium to lead.
The correct answer is: the radioactive decay of uranium to lead.
To determine the age of the Earth, scientists use a method called radiometric dating, which relies on the principle that certain elements decay at a predictable rate over time. In this case, uranium, a radioactive element, decays into lead.
The process begins with zircon, a common mineral found in igneous rocks. Zircon contains small amounts of uranium, which can undergo radioactive decay. By measuring the ratio of uranium to lead in a zircon sample, scientists can calculate the age of the rock.
This method is based on the fact that uranium has a long half-life (4.5 billion years) and decays into lead. By measuring the relative amounts of uranium and lead isotopes in a zircon crystal, scientists can determine how much time has passed since the uranium started decaying.
Various dating techniques, including mass spectrometry, are used to measure the isotopic ratios accurately. By analyzing multiple zircon samples from different locations on Earth, scientists concluded that the Earth is approximately 4.3 billion years old.