How old is the solar system?

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Illustration showing the eight planets of the solar system in order from the Sun-Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune-depicted to scale by size, with labeled diameters in miles and kilometers. The Sun is partially visible on the left for comparison. — Solar system The planets (in comparative size) in order of distance from the Sun.

The solar system is approximately 4.56 to 4.6 billion years old.12

This age is determined by measuring the radioactivity of isotopes found in meteorites, lunar samples, and Earth's crust. Scientists use the decay products of elements such as uranium, thorium, and rubidium to establish this timeline. The birth of the Sun—which formed from the gravitational collapse of a solar nebula—marks the point at which the planets and other orbiting bodies began to form.123