Dating of the earth
In 1953, Clair Cameron Patterson measured ratios of lead isotopes in samples that put tight constraints on Earth's age.The Canyon Diablo meteorite is important because it represents a class of meteorites with components that allow for more precise dating.As science progressed, these methods were proven to be unreliable; for instance, the rise and fall of the ocean was shown to be an ever-changing process rather than a gradually declining one.In an effort to calculate the age of the planet, scientists turned to the rocks that cover its surface.By using not only the rocks on Earth but also information gathered about the system that surrounds it, scientists have been able to place the age of the Earth at approximately 4.54 billion years.For comparison, the Milky Way galaxy that contains the solar system is approximately 13.2 billion years old, while the universe itself has been dated to 13.8 billion years.Earlier research had shown that isotopes of some radioactive elements decay into other elements at rates that can be easily predicted.
These tiny zirconium silicate crystals have ages that reach 4.3 billion years, making them the oldest materials found on Earth so far. The rocks and zircons set a lower limit on the age of Earth of 4.3 billion years, because the planet itself must be older than anything that lies on its surface.
In an effort to further refine the age of Earth, scientists began to look outward.
The material that formed the solar system was a cloud of dust and gas that surrounded the young sun.
Greenland boasts the Isua Supracrustal rocks (3.7 to 3.8 billion years old), while rocks in Swaziland are 3.4 to 3.5 billion years.
Samples in Western Australia run 3.4 to 3.6 billion years old.