What would a lunar impact look like from Earth?
From our point of view on Earth, a large impact on the Moon would most likely be a fascinating and wondrous thing.
Our spacecraft might observe and record the impact itself, and depending on the time of day or night, observers on Earth might be able to see a bright flash. After the impact, we would get to see a new crater appear on the lunar surface. Both of these phenomena have in fact been observed in the past.
If material was ejected from the Moon with enough force to reach the Earth, those small rocks would burn up in the atmosphere much like a meteor shower, creating a beautiful spectacle for us to witness. If any of the pieces of Moon rock were large enough to make it to the surface, they would be unlikely to be large enough to cause damage; they’d be more like particularly scientifically valuable meteorites.
What can we do to prevent asteroids impacting the Moon?
Although an impact on the Moon wouldn’t be harmful to life on Earth, any large asteroid that seems to be heading for an impact with the Moon would be considered potentially hazardous to Earth because of our proximity.
Planetary defense is the effort to find, track, characterize, and — if needed — deflect asteroids that might get close to the Earth-Moon system. The Planetary Society advocates and fundraises in support of planetary defense missions and projects, and space agencies around the world contribute to planetary defense efforts.
DART, NASA’s Double Asteroid Redirection Test, was the first space mission to test an asteroid deflection technique. DART launched in November 2021 and arrived at near-Earth asteroid Didymos in September 2022. On Sept. 26, the spacecraft intentionally crashed into the asteroid’s small moon, Dimorphos. The crash changed the time it takes Dimorphos to orbit Didymos by 33 minutes, proving that the deflection technique of using what’s called a kinetic impactor works.
With proper planning and investment, we will know far in advance if an asteroid is going to impact the Moon, and we can prevent it from even coming close to our planet.