Researchers at University of Wisconsin, Madison, have finally confirmed that blue zircon crystals found in Australia back in 2001 are 4.4 billion years old, making them the oldest known thing on Earth.
The crystals were dug up in Jack Hills in Western Australia and since their discovery, it had been believed that they are billions of years old. Now, Wisconsin University researchers have confirmed the theory, pegging the exact age of these crystals at 4.4 billion years.
In affirming the age of the crystals, these researchers used two distinct methods. One of these methods determined the extent to which uranium found in these crystals has decayed and turned into lead. As a standalone, this method proved insufficient because lead atoms can move around within the crystal over time.
So the researchers decided to use an additional method called atom-probe tomography. This method involved identifying the types of atoms in the crystal and mapping them based on their distribution. As a result of this method, it was confirmed that the lead atoms within the zircon crystals didn’t considerably move, therefore leaving the findings of the first method valid and effective.
The agreed-upon age of the zircon crystals is now 4.4 billion years, with a margin error of 6 million years. A theory says that these crystals were formed when an object having the size of Mars slammed into an early-stage Earth. As a result, the crystals were forged because of the immense heat caused by the collision. The collision resulted in significant drops in Earth’s temperature later, making it possible for water to form and life to happen on this planet.
Source: University of Wisconsin
Courtesy: The Verge