The Earth is old, extremely old. Billions of years ago, the Earth was hit by many asteroids, sending rocks (huge ones) helter-skelter into space.
And, scientists may now have discovered one of those rocks. That rock is the oldest known rock to originate from the Earth, dating back to approximately four billion years. That rock is on the Moon.
The rock, which has been named Big Bertha, was collected by Nasa astronauts Alan Shepard and Edgar Mitchell during the Apollo 14 mission, nearly 50 years ago.
The Apollo 14 crew spent more than 33 hours on the lunar surface and brought home nearly 43 kg of Moon rocks.
This rock, along with other lunar samples, was lying at the Lunar Curation Facility at the Johnson Space Center in the United States.
And it is only now that researchers decided to take a closer look at the "unusual" rock that was brought back the Apollo 14 crew.
Research about this relic has been published in the journal Earth and Planetary Science Letters. Researchers believe that the rock fragment may have originated on the Earth.
Once that information sinks in, imagine how the trajectory of the rock billions of years ago when asteroids hit our planet.
WHAT IS THE ROCK MADE OF?
According to the research, Big Bertha is a two-gram fragment made of quartz, feldspar, and zircon, all commonly found our planet.
Chemical analysis of the rock fragment showed that it crystallised in a terrestrial-like oxidised system, at temperatures found on the Earth, rather than in temperature conditions that are characteristic of the Moon.
"It is an extraordinary find that helps paint a better picture of early Earth and the bombardment that modified our planet during the dawn of life," one of the researchers said.
HOW DID THE ROCK REACH THE MOON?
Available evidence suggests that the fragment crystallised about 20 km beneath the Earth's surface, and was launched into space by a powerful impact shortly thereafter.
At the time of the collision, the Moon was three times closer to Earth than it is today.
After the rock came to rest on the lunar surface, another impact 3.9 billion years ago partially melted and buried it, scientists believe.
The final impact that affected the rock took place about 26 million years ago when an asteroid slammed into the Moon and made the cone crater, measuring 340 metres wide and 75 metres deep, near the Apollo 14 landing site.
The impact resulted in the rock resurfacing, which was then collected by the Nasa astronauts.
The Earth is believed to have been formed in the early Solar System nearly 4.5 billion years ago.
Previously, the oldest known fragment of Earth rock was a zircon crystal from Western Australia. The sliver of material, the same width as two human hairs, has been dated to 4.4 billion years old.