Featured Image Credit: University of Wisconsin-Madison / fotograzia / Getty
We all know the Earth is old, but when you realize Homo sapiens have only been walking on its surface for around 190,000 years of its 4.543 billion-year existence, it puts things into perspective.
Our planet has changed a lot in its time, with the once thriving landmass of Pangea splitting off into the continents and differing ecosystems we see today.
As we continue to make new discoveries on how the Earth was formed and changed over the millenniums, scientists at the University of Wisconsin-Madison discovered the 'oldest' piece of Earth back in 2014.
It's true that the discovery of the blue chunk of zircon isn't the oldest discovery ever made, with that honor going to a speck of interstellar dust.
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Still, this tiny bit of history found in Western Australia's Jack Hills is just as important.
Before you get your hopes up that you'll be able to see some ancient meteorite in the American Museum of Natural History, the zircon is only visible at a microscopic level.
Zircons are a virbant gemstone created from zirconium, and while they come in a variety of colors, blue is the most common.
Still, it's important not to get these naturally occurring zircons confused with the manmade cubic zirconia, which is a manmade alternative known for its use in jewelry.
As for what the discovery means, geoscience Professor John Valley explains how the zircon comes from the Earth's crust that was formed 4.4 billion years ago.
This is just 160 million years after our solar system was formed, with Valley saying it was a time when the Earth was a fiery magma ocean: "This confirms our view of how the Earth cooled and became habitable. This may also help us understand how other habitable planets would form."
Valley is an expert in studying zircons, which are the oldest known terrestrial materials. The discovery builds on earlier research into a 'cool Early Earth', with the Earth's crust formed from a sea of molten rock: "The study reinforces our conclusion that Earth had a hydrosphere before 4.3 billion years ago."
The idea is that life might've come to our humble planet not long after this.
The 2014 study tried the new atom-probe tomography that helped scientists establish the age and 'thermal history' of the zircon. Valley said lead atoms in the zircon were clumped together like "raisins in a pudding" instead of being randomly distributed like originally thought.
Key events in the Earth's evolution occurred when it collided with a Mars-sized object 4.5 billion years ago, which Valley says "formed our moon, and melted and homogenized the Earth." Valley concludes: "Our samples formed after the magma oceans cooled and prove that these events were very early.”
Science suggests it took about 600 million years for the Earth to cool and gain a crust, but thanks to the zircon discovery, it potentially backs up the theory that the crust was formed much earlier.
