Hard hit

 

When the Double Asteroid Redirection Test (DART) impacted asteroid Dimorphos, the little asteroid that orbits the bigger asteroid Didymos, it hit it very, very hard. Astronomers are still figuring out how hard.

NASA's DART asteroid crash really messed up its space rock target

"Lots of incredible information has been gleaned from this impact already, and we just got a little more. According to a paper published this year about the event, DART created a large crater in Dimorphos, in fact reshaping the rock so dramatically it derailed from its original progression."

"One surprise was just how much DART was able to alter Dimorphos. Prior to the collision, the asteroid was oblate, meaning it was somewhat flattened or squished along one axis, likely due to its own rotation or gravitational effects."

After the collision, Dimorphos' shape became prolate, meaning the asteroid was stretched along its axis, making it longer in one direction. The impact likely caused this elongation by redistributing the asteroid's mass and altering its rotational dynamics."

In the actual paper (unless you're a planetary dynamicist, I don't expect you to understand a lot of it), there is a diagram of the shape change, which I grabbed and show below. At least I understand that.