IN THE upcoming film “Moonfall” a mysterious force knocks the Moon on a collision course with Earth.
In the sci-fi flick, which is out this year and stars Halle Berry, the careening object’s inflating gravitational pull triggers apocalyptic tsunamis and yanks huge chunks of rock and debris from our planet’s surface.
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It’s a farfetched idea and all a bit of fun, but could it ever actually happen, and what effect would this have on Earth?
Scientists have chipped in with their theories – with some claiming that our planet is currently on a (very slow) collision course right now.
What would happen if the Moon came closer to Earth?
Speaking to BBC Science Focus magazine on Wednesday, physicist Dr Tony Cook painted a gloomy picture of any would-be close encounter with the Moon.
He said that even if the Moon was half its current distance from Earth, the tides on our planet would be eight times stronger.
“There would be a lot of coastal flooding,” said Dr Cook, a physics lecturer at Aberystwyth University. There would also be “some tsunamis”, he added.
“There would be a lot more gravitational influence on the interior of the Earth, so you might also churn up and heat some mantle, leading to a lot more volcanism and earthquakes.”
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His dreary imaging echoes comments made by astronomer and author Gemma Lavendar.
Writing in the magazine All About Space in 2018, she predicted that lunar flyby would trigger massive, deadly waves that would batter coastal regions.
“Moving the Moon closer to the Earth will increase the gravitational exertion of the satellite onto our planet,” she wrote.
“Low tides would be lower and high tides would be higher and any low lying coastline would be flooded.
“If the Moon got much closer, say 20 times closer, it would exert a gravitational force 400 times greater than what we are used to.
“A mighty tidal bulge would be created, hitting the land and causing great flooding, with cities such as London and New York disappearing under water.”
Could the Moon ever hit us?
Some scientists believe that the Moon really will collide with Earth – albeit in a few tens of billions of years’ time.
Our rocky neighbour is thought to be spinning away from us at a rate of roughly 3.8 centimetres per year.
However, over time the Earth’s rotation will slow until such a point that the Moon stops moving outward.
Assuming the Solar System hasn’t been swallowed by the explosion of our Sun by then, the satellite will start to creep inwards until it hits our planet.
“The final end-state of tidal evolution in the Earth-Moon system will indeed be the inspiral of the Moon and its subsequent collision and accretion onto Earth,” Jason Barnes, a planetary scientist at the University of Idaho, told Forbes in 2017.
That’s all well and good over geological timescales, but what about our natural satellite suddenly dropping from space, like in “Moonfall”.
Dr Cook told Science Focus that we’ve nothing to worry about on that front.
There’s an equilibrium between the Earth and the Moon called the barycentre, he said, which the two bodies rotate around.
This point is closer to the Earth than the Moon, inside Earth’s surface – if left alone, that point won’t change, and there’s no real risk of a collision.
Trailers for Moonfall suggest that, in the movie, an alien force has knocked the Moon off of its orbit.
That’s something that would take a long period of time and would likely require a series of rocket thrusters to be strapped to the Moon.
“You would need an enormous amount of energy to do that, and probably have to do it gently otherwise the Moon might fall to pieces,” Dr Cook said.
“A similar method has been proposed to change the direction of asteroids.”
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In other news, a four-tonne chunk of a SpaceX rocket is on a collision course with the Moon, according to online space junk trackers.
Boeing has sunk $450million into a flying taxi startup that hopes to whisk passengers across cities by the end of the decade.
Personalised smart guns, which can be fired only by verified users, may finally become available to U.S. consumers this year.
And, scientists are embarking on a mission to unravel the mystery behind dozens of grisly child mummies buried in an underground tomb in Sicily.
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This post first appeared on Thesun.co.uk
