Oldest known Earth fragment discovered


Scientists have identified a zircon crystal in Australia that dates back more than 4.375 billion years.

Among some of the toughest materials on the planet, Zircons are important to scientists as not only can they survive the tumultuous conditions that followed the Earth's formation but some can also trap small bubbles of gas from the planet's earliest atmosphere.

The discovery in Australia of a crystal dating back to just 165 million years after the Earth formed has therefore provided experts with a unique opportunity to learn more about the atmospheric conditions at that time. What they discovered was that the Earth is likely to have cooled within just 100 million years of the collision that brought about the formation of the moon.

"The zircons show us the earliest Earth was more like the Earth we know today," said geochemist John Valley who lead the study. "It wasn't an inhospitable place."
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