# Could a planet have a massive crater without collapsing due to gravity / other factors?

A severely destroyed planet is a popular trope in media. Here are a few examples from fiction with pictures (spoiler warning).

• A crater with a diameter 1/3rd the size of the planet itself:

• A crater so large that nearly half of the planet is missing:

Concord Dawn (Star Wars) https://starwars.fandom.com/wiki/Concord_Dawn?file=Concord_Dawn_system.png

• A planet so destroyed that only a sliver remains, still maintaining the crescent shape of the partial sphere:

Earth in 2091 (Marvel) https://marvelcinematicuniverse.fandom.com/wiki/2091?file=Earth.png.jpg

• A planet cracked in half with both halves offset from each other:

Gem Homeworld (Steven Universe) https://steven-universe.fandom.com/wiki/Gem_Homeworld?file=Legs_From_Here_to_Homeworld_366.png

I know that the physical behavior of objects changes dramatically with scale, one example being the anatomical differences between insects and elephants. I would imagine, at a planetary scale, that the last three examples may just collapse back into a spherical shape because of gravity.

Could these planetary bodies actualy maintain the shape we see in fictional media?

• You can check pictures of Rheasilvia crater on Vesta asteroid. en.wikipedia.org/wiki/Rheasilvia. Mars is theorised to have a giant impact too, but the all we can see now - the Northern hemisphere of Mars has several kilometers lower altitude than the Southern hemisphere, in average. Sep 8, 2022 at 9:55

The short answer is no! But the process would take time. If we imagine that some impact causes the crater at some $$t_0$$ in the past, then the exact time frame on which the planet would begin to warp is uncertain and would depend entirely on the interior dynamics. Assuming all of these were Earth-like planets, they would all return to some "sphere-like" shape in the far future because of the plasticity of the planet. However, if you somehow created a planet which was rigid enough to resist any inhomogeneous forces due to gravity, you could see craters like these last indefinitely. What makes planets reshape is really that they are not entirely rigid in their dynamics.