Could the moon ever be knocked out of orbit like it was in Moonfall?
The moon has been Earth’s close companion for billions of years, and while our view of its shape and size varies somewhat as it orbits our planet, it remains a constant presence in the sky. But could that change?
In the 2022 movie Moonfall (Lionsgate, released February 4), a mysterious force pushes the moon from orbit and drives it towards on a collision course Earth, with a planet-shattering impact looming in just a few short weeks. (Warning, spoilers ahead.) When faced with this risky and over-the-top disaster scenario, the film’s characters strive to save the planet. In the process, they learn that our natural Trabant is not all that natural.
The notion of the moon as an artificial megastructure built by intelligent aliens billions of years ago is firmly entrenched in the realm of science fiction. But is there a naturally occurring object in space that could actually push the moon out of orbit? With tens of thousands of asteroids and comets Could a collision with a large enough rock ever turn the moon into a projectile that could crash to earth?
Related: What if the moon disappeared tomorrow?
A solid, rocky body surrounded by a very thin layer of gas known as the exosphere, our moon is the natural satellite that formed at about the same time as Earth, about 4.5 billion years ago. A widely accepted hypothesis holds that the moon formed from rocky debris after a massive impact between a young Earth and a smaller protoplanet: a hypothetical object called Theia, according to NASA. Another collision hypothesis holds that both the Moon and Earth were formed after the collision of two bodies each five times the size of Mars, NASA says.
The moon is about 239,000 miles (385,000 kilometers) from Earth and has an estimated mass of more than 81 million tons (73.5 million tons). It’s about a quarter the size of Earth; If the earth were the size of a nickel, the moon would be about the size of a pea, according to NASA.
Images of the moon show that its surface is riddled with craters of various sizes, formed by past impacts. But most of these were made billions of years ago, when a lot more debris shot through the earth solar systemsaid Paul Chodas, manager of the Center for Near Earth Object Studies (CNEOS) for NASA’s Jet Propulsion Laboratory at Caltech in Pasadena, California. Most of the planet-forming rocky debris that once filled the solar system has long since dissipated, “so the number of impacts is now greatly reduced — there’s a lot less material that can hit the Earth or the Moon,” Chodas told Live Science .
CNEOS identifies and tracks Near Earth Objects (NEOs) such as asteroids and comets to determine if they pose a threat to Earth, the Moon, or our other cosmic neighbors, according to the center’s website. To date, CNEOS is tracking approximately 28,000 NEOs – objects that are within 1.3 astronomical units (120.9 million miles or 194.5 million km) of Earth.
“We look for collisions between planets and asteroids, and we look for collisions on the moon,” he said. In general, asteroid collisions with the moon are much less likely than collisions with Earth, since our planet is a more massive target with stronger ones heaviness. A wayward space rock invading our cosmic neighborhood would therefore be drawn to Earth rather than the Moon, Chodas explained.
Size also matters when scientists consider the risk of a speeding asteroid. For a NEO to be classified as a threat to Earth, it must be at least 460 feet (140 meters) in diameter, according to NASA. And for an asteroid impact to affect the moon’s orbit, the asteroid would have to be at least as big as the moon itself, Chodas said.
“The moon is big, so it would have to be a huge object that would have to hit it at high speeds,” he said. “You’d have to hit it with something hundreds and hundreds of kilometers across.”
Related: What does it take to be a moon?
Fortunately for us (and for the moon), none of the known asteroids in the solar system are anywhere near the size of the moon. The largest known asteroid is about 70 times less massive than the moon and orbits between Mars and Jupiter in the main asteroid belt, about 112 million miles (180 million km) from Earth. according to NASA.
That might rule out the possibility of a solar system asteroid displacing the moon, but what about a man-made object? Coincidentally, a spent SpaceX Falcon 9 rocket booster stage, launched in 2015, is currently on a crash course with the moon and is expected to impact it in March 2022. Live Science previously reported.
The rocket segment, which weighs about 4.4 tons (4 tons), ran out of fuel after the orbital placement of the Deep Space Climate Observatory (DSCOVR), a satellite used to monitor Earth’s climate and solar storms and a joint NASA-US project from National Oceanic and Atmospheric Administration. The now empty booster will be traveling at approximately 9,288 km/h (5,771 mph) when at 4 meters (13 ft) in diameter, The New York Times reported.
There is no risk that the crash will affect the moon’s orbit; Even so, CNEOS is closely monitoring the rocket’s trajectory, though it doesn’t typically track man-made objects in space, Chodas told Live Science.
“We do some calculations specifically for this object,” he said. “This one is of interest to the LRO spacecraft [NASA’s Lunar Reconnaissance Orbiter]orbiting the moon and could take a picture of the crater, so they’d like to know where it’s going to hit. And we can work out the predictions of where to look and where that crater will be in a month.”
So the next time you look at the moon in the night sky, comfort yourself with the thought that it’s not going anywhere anytime soon.
Originally published on Live Science.