HUGE fragments of an alien world may be buried deep beneath the surface of our planet.
A study has identified blobs of rock under Earth’s crust that possibly belonged to Theia, a Mars-sized planet thought to have collided with our pale blue dot billions of years ago.
The almighty crash is believed to have created the Moon – and remnants of the impact may lurk deep within our planet's mantle.
Researchers at Arizona State University used seismic waves to track the size of the strange blobs, known as large low-shear-velocity provinces (LLSVPs).
Two of the gigantic masses were studied: One buried under Africa and the other below the Pacific Ocean.
They're hundreds of miles tall and thousands of miles across, sitting close to our planet's metallic core, the study found.
Author Qian Yuan says the blobs "straddle the Earth's core like headphones".
They are denser and chemically different to the rock surrounding them, suggesting the weren't originally a part of our planet.
Theia's mantle was denser than Earth's, according to Yuan, which may have allowed it to accumulate near our planet's core following impact.
"Theia's mantle may be several per cent intrinsically denser than Earth's mantle," Yuan explained in a summary of the team's findings presented last week at the Lunar and Planetary Science Conference.
"This enables the Theia mantle materials to sink to the Earth's lowermost mantle and accumulate into thermochemical piles that may cause the seismically-observed LLSVPs."
Experts have long believed that a rogue, Mars-sized planet smashed into Earth around 4.5billion years ago.
The impacting planet, referred to as Theia, is thought to have fused with Earth, meaning parts of it should exist in the mantle today.
Chemical exchanges in the wake of this violent merger may have created the conditions for life on our planet.
The collision is thought to have thrown up vast clouds of material that gravity later fused together to form the Moon.
A timeline of life on Earth
Here’s a brief history of life on our planet
- 4.6billion years ago – the origin of Earth
- 3.8billion years ago – first life appears on Earth
- 2.1billion years ago – lifeforms made up of multiple cells evolve
- 1.5billion years ago – eukaryotes, which are cells that contain a nucleus inside of their membranes, emerge
- 550million years ago – first arthropods evolve
- 530million years ago – first fish appear
- 470million years ago – first land plants appear
- 380million years ago – forests emerge on Earth
- 370million years ago – first amphibians emerge from the water onto land
- 320million years ago – earliest reptiles evolve
- 230million years ago – dinosaurs evolve
- 200million years ago – mammals appear
- 150million years ago – earliest birds evolve
- 130million years ago – first flowering plants
- 100million years ago – earliest bees
- 55million years ago – hares and rabbits appear
- 30million years ago – first cats evolve
- 20million years ago – great apes evolve
- 7million years ago –first human ancestors appear
- 2million years ago – Homo erectus appears
- 300,000 years ago – Homo sapiens evolves
- 50,000 years ago – Eurasia and Oceania colonised
- 40,000 years ago – Neandethal extinction
Analysis of Moon rocks has suggested that our rocky satellite could actually be a combination of chunks of Earth and Theia.
The idea that LLSVPs are in fact remnants of Theia has been around for years, but the new study presents the most compelling evidence yet.
The study reveals that chemical signatures linked to LLSVPs are at least as old as the Theia impact.
While it's not conclusive proof that ties them to an ancient alien world, it certainly shows that the theory is plausible.
"This crazy idea is at least possible," Yuan, a PhD candidate at ASU, told Science.
In other space news, the DNA of 6.7 million species could be stored inside the Moon in case there's a disaster that destroys life on Earth.
The largest asteroid to make a 'close approach' to Earth in 2021 is set to shoot past this month.
Nasa has released historic first audio recordings captured on the surface of Mars.
What do you make of the Theia find? Let us know in the comments…
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