What would REALLY happen if an asteroid struck the ocean: Simulation reveals impact would launch BILLIONS of tons of water into the atmosphere

If it hit far from coastlines, massive waves would die down before hitting cities
But, impact would have devastating effects if within 10-20km from the coast
Bigger threat would come from billions of tons of water vapor injected in the air
This could loft into the stratosphere and linger for months, altering the climate

Published: 22:00 GMT, 14 December 2016 | Updated: 23:03 GMT, 14 December 2016

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If an asteroid were to slam into Earth, there’s a strong chance it would end up at sea, with oceans covering roughly 70 percent of our planet’s surface.

An impact would have devastating effects if it occurred within 10-20 kilometers of a city's coastline, potentially killing thousands of people - but if it hit out in the middle of the ocean, the massive waves generated by the collision would quickly die down.

A new simulation reveals that the destructive waves would be unable to travel long distances, preventing city-swallowing tsunamis from reaching the shorelines.

Water vapour, instead, could pose a larger threat – the impact would launch billions of tons of the greenhouse gas into the air, with potential to linger in the stratosphere for months or even years.

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The visualization from the Los Alamos National Laboratory shows what would happen if an asteroid slammed into the ocean. This revealed that, if it occured far from the coastlines, the threat of a tsunami hitting cities would be low. But, water vapour would pose a greater risk

WHAT WOULD HAPPEN

If an asteroid struck the ocean, the researchers say it would create a transient crater, launching a splash curtain into the air.

As water rushes into the crater, a jet would form - and this could be several kilometers high.

The jet would then collapse to form a rim wave, which would be hundreds of meters high.

A new water jet would form, and create a new rim wave, and the process would go on.

Each rim wave has potential to become a tsunami, the researchers explain.

Far away from the coastlines, however, the risks to populated areas would be low.

A larger threat may come from the large amounts of water vapour sent into the air, which would be lofted into the stratosphere.

The greenhouse gas could linger for months or years, with severe implications for the global climate.

The new visualization from the Los Alamos National Laboratory comes as a result of NASA’s Second International Workshop on Asteroid Threat Assessment.

Given the likelihood of an asteroid making impact with the ocean if it were set to hit Earth, the researchers explored what the risks of a resulting tsunami would be.

Scientists at LANL used high performance computing to investigate how an asteroid’s kinetic energy is transferred to the atmosphere and the ocean.

They created simulations with varying asteroid size, angle of impact, and whether or not it exploded in an airburst.

The simulations focused on three materials: basalt asteroid, static air, and static water.

The investigation revealed that more kinetic energy would be transferred to the water, and in the largest scenario, the visualization shows how a 250-meter-wide asteroid could create a transient crater, giving rise to a massive plume of water and water vapour.

But, the researchers say, colliding shockwaves in the atmosphere and water, along with the wind at the water’s surface would hinder the creation of a propagating wave.

Scientists at LANL used high performance computing to investigate how an asteroid’s kinetic energy is transferred to the atmosphere and the ocean. They created simulations with varying asteroid size, angle of impact, and whether or not it exploded in an airburst

It also revealed that a direct impact with the water would be more likely to create a tsunami than an airburst would, in contrast to what’s previously been thought.

An airburst would break the asteroid apart, the researchers explain, causing much of it to skim the surface rather than slamming into it.

Even if it wouldn’t travel hundreds of miles to threaten cities, an asteroid that hit the ocean would still create waves of staggering enormity.

‘Immediately upon impact, a transient crater is created and a splash curtain is thrown high into the air,’ the researchers explain.

An impact would have devastating effects if it occurred within 10-20 kilometers of a city's coastline, but if it hit out in the middle of the ocean, the massive waves generated by the collision would quickly die down. Stock image

'NOTHING WE CAN DO' ABOUT AN ASTEROID IMPACT, EXPERTS WARN

Experts have warned that humans are not prepared for an asteroid impact, and should one head for Earth, there's not much we can do about it.

A Nasa scientist has said that our best hope is building an interceptor rocket to keep in storage that could be used in deflection missions.

Dr Joseph Nuth, a researcher at Nasa's Goddard Space Flight Centre in Maryland was speaking at the annual meeting of the American Geophysical Union earlier this week.

He said: 'The biggest problem, basically, is there's not a hell of a lot we can do about it at the moment.'

While dangerous asteroids and comets rarely hit Earth, Dr Nuth warned that the threat was always there.

He said: 'They are the extinction-level events, things like dinosaur killers, they're 50 to 60 million years apart, essentially.

'You could say, of course, we're due, but it's a random course at that point.'

‘Water rushes into the crater forming a water jet which can be several kilometers high. This jet collapses to form a rim wave, which is hundreds of meters high.

‘A new water jet begins to form and to, in turn, create a new rim wave, a process that continues for some time.

‘Each of these rim waves has the potential to become a tsunami.’

The researchers also noted another threat of ‘equal importance.’

An asteroid impact out at sea would send large amounts of water vapour into the air, which would be lofted into the stratosphere.

According to the team, this could linger for months or even years, and as it is a greenhouse gas, there would be severe implications for the global climate.