Researchers have found that 'peak rings' - a mountainous ring of smashed rocks inside an asteroid crater's outer rim - is a product of extremely strong vibrations that made rock flow like liquid following an impact.
The scientists, from Purdue University, published a new study about the phenomenon in the journal Nature, documented how this was the case at impact crater Chicxulub, which is said to be the remnants of the asteroid that killed off the dinosaurs.
The crater lies underneath the Yucatán Peninsula of Mexico, and is said to be the best-preserved example of its kind on Earth.
These findings help us understand how impact craters collapse and how large masses of rock behave in a fluid-like manner in other circumstances, such as landslides and earthquakes
Although it's buried underneath a half mile of rocks, the scientists said how its outer rim features formed has long been debated.
However, now they found that when an asteroid crashes into Earth, it leaves a bowl-shaped pit, just like you'd expect. But it doesn't just leave a dent. If the asteroid is big enough, the resulting crater can be more than 20 miles deep, at which point it becomes unstable and collapses.
"For a while, the broken rock behaves as a fluid," said Jay Melosh, a professor of earth, atmospheric and planetary sciences at Purdue University.
"There have been a lot of theories proposed about what mechanism allows this fluidisation to happen, and now we know it's really strong vibrations shaking the rock constantly enough to allow it to flow."
This mechanism, known as 'acoustic fluidisation', is the process that enables the ring of mountains in the crater's center to rise within minutes of the asteroid's strike.
The Chicxulub crater isn't easily accessible by traditional standards either: it's been buried for the past 66 million years. So the International Ocean Discovery Program drilled a core roughly six inches in diameter and a mile into Earth in order to collect rock that was shattered and partly melted by the impact that wiped out the dinosaurs.
Towns have been wiped out by enormous landslides, where people thought they were safe but then discovered that rock will flow like liquid when some disturbance sets a big enough mass in motion
Examining fracture zones and patterns in the core, the international research team found an evolution in the vibration sequence that would enable debris to flow.
"These findings help us understand how impact craters collapse and how large masses of rock behave in a fluid-like manner in other circumstances, such as landslides and earthquakes," Melosh said.
"Towns have been wiped out by enormous landslides, where people thought they were safe but then discovered that rock will flow like liquid when some disturbance sets a big enough mass in motion."
The researchers believe that the extinction of the dinosaurs itself was probably not directly affected by the crater's internal collapse.
"Regardless, it's important to understand the consequences of a large asteroid strike on Earth," the report notes. "Because cratering is the same on all the terrestrial planets, these findings also validate the mechanics of impacts everywhere in the solar system."
US space agency believes the crater could have preserved ancient organic molecules from the water that flowed there billions of years ago
Valve quietly closes down hardware initiatives launched following Windows 8
Scientists create a virtual reality simulation of a black hole sitting at the centre of the Milky Way
Simulations like this can help people understand complicated systems in the universe in a better way
The most luminous galaxy ever discovered is cannibalising at least three of its smaller neighbours, study finds
The galaxy radiates at 350 trillion times the luminosity of the Sun