A nine-mile (15km) wide crater caused by a meteorite collision has been unearthed off the coast of north west Scotland.
The space rock which was more than half a mile across (1.5km) caused ‘Britain’s biggest meteorite crater in history’ 1.2 billion years ago.
It was caused by a 13 billion ton meteorite that crashed near the town of Ullapool – part way across The Minch towards Stornoway in the Outer Hebrides.
The object was travelling at more than 40,000 miles per hour (65,000kph) and struck the Earth with the force of 940 million Hiroshima bombs.
This left a crater beneath the North Atlantic that has lay buried deep under the sea floor.
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Britain’s biggest meteorite crater – caused by a space rock more than half a mile across (1 to 2km) has been unearthed off the coast of north west Scotland. This bank of sandstone at Stoer hints at the deformation of the sea floor caused by the impact
Scientists from the University of Oxford first discovered evidence of the ancient strike eleven years ago and have now finally pinpointed its precise location.
It lies under the Minch, the rough sea that separates Lewis in the Outer Hebrides from the far Highlands of Scotland, between 9.3 and 12.4 miles (15 and 20km) west of a remote part of the beach.
They first found evidence that a structure lies between the Western Isles and mainland Scotland back in 2008.
They found evidence on the Highlands coast of rocky debris that would have been produced by a giant impact.
Now, the team, from Oxford and Aberdeen universities, believes it can pinpoint where the object fell to Earth.
Lead author Dr Ken Amor, an earth scientist at the University of Oxford, told MailOnline that a large rock struck the Earth and the asteroid made a crater in the sea.
‘Material gets thrown out into the atmosphere, which is a mixture of molten rock fragments, hot gas and pulverised rock which spreads out.
‘This plume cloud, then collapses and starts travelling around and spreading out across the landscape, eventually coming to a halt.
The team took measurements from the outcrop, or bed rock, to find directional information and therefore find out where the impact may have been.
‘We’ve inferred where it is and that it is buried under two metres of water,’ he said.
‘The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery.
‘It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it.
‘The next step will be a detailed geophysical survey in our target area of the Minch Basin, which is something like what they would use in the oil industry.’
Dr Amor said that a 3D seismic survey would be the best way to pinpoint the crater – which will cost hundreds of thousands of pounds.
The space rock lies under the Minch, the rough sea that separates Lewis in the Outer Hebrides from the far Highlands of Scotland. Pictured: Spheres that formed in the plume of debris thrown up by the impact
The crater was caused by the impact of a 13 billion ton meteorite that crashed near the town of Ullapool 1.2 billion years ago. Pictured: A view of ‘shocked quartz’ which is evidence of the ancient asteroid impact
Working with colleagues at the University of Aberdeen, he first found debris believed to have been flung out in the collision in 2008.
The thickness and extent of the deposit suggested it was near the coast – but the exact site remained a mystery.
If humans had been around then they would have seen quite a show. It would have melted rocks and thrown up an enormous cloud of vapour.
This scattered material over a large part of the region around Ullapool. The crater was rapidly buried by sandstone which helped to preserve the evidence.
So the researchers plotted the spot by mapping the direction the meteorite material took at several locations.
The object, which was travelling at more than 40,000 miles per hour (65,000kph), struck the Earth with the force of 940 million Hiroshima bombs (artist’s impression)
The study was based on field observations, the distribution of broken rock fragments and the alignment of magnetic particles.
Unusual rock formations in the area were previously thought to have been formed by volcanic activity.
But Dr Amor and colleagues found evidence of a phenomenon known by geologists as ‘ejecta blanket’.
This represents debris thrown out when a huge object slams into the ground. The material from the meteorite strike is scattered over an area about 50km (31 miles) across.
In the rocks, there were also elevated levels of the element iridium, which is characteristic of extra-terrestrial material. There were also microscopic parallel fractures that also imply a meteorite strike.
Dr Amor said: ‘It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area.’
WHAT ARE THE DIFFERENT TYPES OF SPACE ROCKS?
An asteroid is a large chunk of rock left over from collisions or the early solar system. Most are located between Mars and Jupiter in the Main Belt.
A comet is a rock covered in ice, methane and other compounds. Their orbits take them much further out of the solar system.
A meteor is what astronomers call a flash of light in the atmosphere when debris burns up.
This debris itself is known as a meteoroid. Most are so small they are vapourised in the atmosphere.
If any of this meteoroid makes it to Earth, it is called a meteorite.
Meteors, meteoroids and meteorites normally originate from asteroids and comets.
For example, if Earth passes through the tail of a comet, much of the debris burns up in the atmosphere, forming a meteor shower.
The crater lies under the Minch, the rough sea that separates Lewis in the Outer Hebrides from the far Highlands of Scotland, between 9.3 and 12.4 miles (15 and 20km) west of a remote part of the beach (pictured)
At the time, most life was still in the oceans and there were no plants on the land. Scotland would have been quite close to the equator and in a semi-arid environment.
The landscape would have looked a bit like Mars when it had water at the surface. Earth and other planets may have suffered a higher rate of meteorite impacts.
In the distant past, they collided with debris left over from the formation of the early solar system.
However, there is a possibility a similar event will happen in the future given the number of asteroid and comet fragments floating around in the solar system.
It is thought collisions with an object this size occur between once every 100,000 years to once every one million years – but estimates vary.
One of the reasons for this is our terrestrial record of large impacts is poorly known because craters are obliterated by erosion, burial and plate tectonics.
Much smaller impacts, where the meteorite is only a few meters across are thought to be relatively common – perhaps happening about once every 25 years on average.
The largest crater made by a meteor or comet was discovered in the Australian outback four years ago.
It has a 250-mile diameter and is believed to have occurred more than 300 million years ago.
Other craters include the 100 mile wide Vredefort Dome in South Africa created over 2,000 million years ago and the 93 mile wide Chicxulub buried beneath Mexico’s Yucatan Peninsula – the most famous of them all.
It was created by an asteroid 66 million years ago – and is believed to have been responsible for wiping out the dinosaurs.
The full findings of the study were published in the
WHAT IS A METEOROID?
A meteoroid is a small chunk of asteroid or comet.
When it enters Earth’s atmosphere it becomes a meteor, fireball or shooting star.
The pieces of rock that hit the ground are meteorites, and are valuable to collectors.
The remnants must be analyzed by a lab to be accredited as meteorites.