Extraterrestrial impacts may have formed the Earth 3.2 billion years ago, the study finds
The rocky surface of the Earth is the result of an “intense bombing” of alien impacts that hit the surface billions of years ago
- Experts say that impacts from space have caused the emergence of tectonic plates on Earth
- Layers of round particles condensed from the impact were discovered
- Particles date about 3.2 million years ago, similar to when plates appeared
Researchers suggest that the rocky earth that we know today is a result of extraterrestrial influences from billions of years ago.
A new study has shown that plate tectonics was caused by an intense bombing of meteors – the hot, ancient mushy surface transformed into the current rugged landscape.
The team discovered distinctive layers of round particles condensed from rock evaporated during a collision suggesting that the earth experienced a period of intense bombing about 3.2 billion years ago – similar to when the first tectonics appeared.
Craig O’Neill, director of the Planetary Research Center at Macquarie University, said: “We tend to view the earth as an isolated system, where only internal processes matter.”
“However, we are increasingly seeing the effect of the dynamics of the solar system on how the Earth behaves.”
Using modeling simulations and comparisons with lunar impact studies, the team discovered that after the earth’s growth around 4.6 billion years ago, the planet’s impact continued to be hundreds of millions of years.
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The team discovered distinctive layers of round particles (pictured) condensed from rock evaporated during a collision suggesting that the earth experienced a period of intense bombing about 3.2 billion years ago – similar to when the first tectonics appeared.
The data suggest that the impact decreased over time, the team was able to find evidence of distinctive layers of round particles condensed from rock evaporated during an alien impact found in South Africa and Australia
These findings suggest that the earth experienced a period of intense bombing about 3.2 billion years ago, which are the first indications of plate tectonics appearing in the rock record.
And O’Neil and co-authors of the study wondered if this could all be related.
“Earliest soil model studies suggest that very large impacts – more than 300 km in diameter – can cause significant thermal deviation in the mantle,” O’Neill said.
This seems to have sufficiently changed the buoyancy of the mantle to create ascents that, according to O’Neill, “can directly cause tectonics.”
But the scarce evidence found to date from the Archeic area, the period from 4.0 to 2.5 billion years ago, suggests that usually smaller impacts of less than 62 miles in diameter occurred during this interval.
To determine whether these effects were worthy to activate global tectonics, the team used existing ones techniques to expand the Middle Archaean impact record and subsequently developed numerical simulations to model the thermal effects of these impacts on the earth’s mantle.
They found that during the Middle Archaic, 62-mile-wide collisions were able to weaken the rigid, outermost layer of the earth.
O’Neill stated that this could have acted as a trigger for tectonic processes, especially if the outside of the earth was already “ready” for subduction.
The modeling showed that if an impact were to occur in an area where these differences existed, this would create a point of weakness in a system that already had a great contrast in buoyancy – and eventually triggered modern tectonic processes (artist impression)
“If the lithosphere had the same thickness everywhere, such effects would have little effect,” says O’Neill.
But during the Middle Archean, he said, the planet had cooled sufficiently so that the cloak became thicker in some places and thin in others.
The modeling showed that if an impact were to occur in an area where these differences existed, this would create a point of weakness in a system that already had a great contrast in buoyancy – and eventually triggered modern tectonic processes.
“Our work shows that there is a physical link between impact history and tectonic response around the time when plate tectonism would have started,” O’Neill said.
“Processes that are fairly marginal these days – such as influencing, or, to a lesser extent, volcanism – have actively powered early tectonic systems.”
“By investigating the implications of these processes, we can begin to investigate how the modern habitable earth came into existence.”
WHAT ARE TECTONIC PLATES?
Tectonic plates are composed of the earth’s crust and the upper part of the mantle.
Below is the asthenosphere: the warm, viscous rock conveyor on which tectonic plates run.
The earth has fifteen tectonic plates (photo) that together have shaped the shape of the landscape that we see around us today
Earthquakes usually occur at the borders of tectonic plates, where one plate protrudes below another, pushes another up, or where the plate edges scrape past each other.
Earthquakes rarely occur in the center of plates, but they can happen when old faults or fissures reactivate far below the surface.
These areas are relatively weak compared to the surrounding plate and can easily slip and cause an earthquake.