It's true that we can't necessarily say that the earth must be round because all other celestial bodies are round.
But we do ask why WOULDN'T the Earth be round if all other celestial bodies are round?
A sphere happens in nature so much because it's the shape that naturally forms when atoms congregate around a point (in this case, the gravitic core). Atoms are attracted and get as close as they can, "falling" toward the center. If there's a place that's closer that they can go, that's where they go. Eventually, all empty space around the center is filled up, forming the sphere.
It's why most of our cells tend to form spheres as well. The most energy-efficient system of transporting materials and nutrients will be in a sphere. This also accounts for why cells generally can't get too big: it becomes impossible for the organelles to effectively keep up, since expanding the surface area of a sphere disproportionately and dramatically increases its volume.
So if all observable free matter in the universe observably forms spheres, then it's a reasonable assumption to make that Earth would be no different. It's true that it isn't a flawless assumption, but it's a fair generalization that requires justification to reject.
If Earth isn't forming a sphere like literally all other matter we can see and when recreating similar testable conditions, then what's different about Earth that makes it worthy of exemption?
It's true that we can't necessarily say that the earth must be round because all other celestial bodies are round.
But we do ask why WOULDN'T the Earth be round if all other celestial bodies are round?
A sphere happens in nature so much because it's the shape that naturally forms when atoms congregate around a point (in this case, the gravitic core). Atoms are attracted and get as close as they can, "falling" toward the center. If there's a place that's closer that they can go, that's where they go. Eventually, all empty space around the center is filled up, forming the sphere.
It's why most of our cells tend to form spheres as well. The most energy-efficient system of transporting materials and nutrients will be in a sphere. This also accounts for why cells generally can't get too big: it becomes impossible for the organelles to effectively keep up, since expanding the surface area of a sphere disproportionately and dramatically increases its volume.
So if all observable free matter in the universe observably forms spheres, then it's a reasonable assumption to make that Earth would be no different. It's true that it isn't a proven assumption, but it's a fair generalization that requires justification to reject.
If Earth isn't forming a sphere like literally all other matter we can see and when recreating similar testable conditions, then what's different about Earth that makes it worthy of exemption?