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How Old Do Scientists Believe the Earth Is?

Published in Science 2 mins read

Scientists believe the Earth is approximately 4.54 billion years old. This age is determined through various methods, primarily radiometric dating.

Radiometric Dating: A Key Tool

Radiometric dating relies on the decay of radioactive isotopes within rocks. These isotopes decay at a predictable rate, known as their half-life. By measuring the ratio of parent isotopes to their decay products, scientists can calculate the age of the rock.

Evidence from Different Sources

Evidence supporting this age comes from multiple sources:

  • Meteorites: Many meteorites, remnants from the early solar system, have been dated to around 4.56 billion years old.
  • Lunar Samples: Rocks brought back from the Moon by Apollo missions have also been dated to approximately 4.5 billion years old.
  • Earth's Oldest Rocks: The oldest known rocks on Earth, found in the Canadian Shield, are about 4 billion years old.

Understanding the Earth's Formation

These findings indicate that the Earth formed shortly after the solar system itself, around 4.6 billion years ago. The early Earth was a very different place, with a molten surface and a constant bombardment of asteroids and comets. Over time, the Earth cooled and differentiated, eventually forming the continents and oceans we know today.

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