Isotopic dating of solar system materials indicates an age of approximately which value?

• A. 3.0 billion years ago
• B. 4.57 billion years ago
• C. 4.0 billion years ago
• D. 4.9 billion years ago

Answer: (B)

Isotopic dating uses the known rates of radioactive decay to measure how long ago minerals solidified. When this clock is applied to ancient solar system materials like meteorites and the first solids inside them, the measured parent-to-daughter isotope ratios give a formation time of roughly 4.57 billion years ago. This value comes from well‑established dating methods (such as uranium–lead) and is supported by multiple independent isotopic systems, all pointing to the Sun and planets forming about 4.6 billion years ago. The other numbers are simply too young or too old compared to the oldest dated solar system materials, which fall near this 4.57 Ga mark.