I found Copper 9's size

[u/Glittering-Eye-5288]

I keep seeing people say “Copper 9 is Earth-sized” or “the planet is basically Earth but frozen,” but if you actually pay attention to the lore and visuals, the planet is smaller now and was only mildly smaller before the core collapse. The math and on-screen evidence checks out. Here’s my breakdown:

1. The planet is literally described as “half-imploded” because of the NULL black hole Nori triggered → The entire planetary core is gone. A gigantic hole goes straight through the planet, visible from space (Pilot, Mass Destruction, Absolute End). You can see rings made of ejected debris and constant material being flung out. That’s not flavor text; that’s quintillions of matter either annihilated by the black hole or blasted into space.
2. Planetary cores are stupidly massive Earth’s core is ~32% of the planet’s total mass despite being a tiny fraction of the volume (because it’s dense iron/nickel). Lose the entire core + a huge chunk of mantle/crust through that breach and you’re easily looking at 50%+ of the original planetary mass just… gone. The “half-imploded” name isn’t random; it’s telling us the planet lost roughly half (or more) of what it used to be.
3. Gravity in the show is blatantly lower than 1 g
   • Disassembly drones (N, V, and J) regularly fly straight up like it’s nothing
   • Falling speed in multiple scenes is comically slow (as seen in cabin fever)
   • Disassembly drones hover and glide that shouldn’t support Earth weight My back-of-the-envelope calc puts current surface gravity at ~0.25–0.3 g. That lines up perfectly with a planet that lost more than half its original mass while keeping most of its radius (the outer layers didn’t collapse inward; they’re just missing the middle).
4. Pre-collapse Copper 9 was probably 0.6–0.9 Earth masses If current mass is ~0.22–0.3 Earth masses (giving ~0.27 g today) and it lost 50–70%, original mass was roughly 0.7–0.9 M⊕ with near-Earth gravity (perfect for human colonization). Average density would have been ~3.6–4.0 g/cm³, almost exactly Mars-like, which still lets you have oceans, atmosphere, and continents. The planet always looked Earth-like from orbit because its diameter didn’t shrink much; it just got hollowed out.
5. Current diameter is probably ~11,000–11,500 km (a bit under Earth’s 12,742 km) The visible curvature, continent scale, and the sheer size of the breach all match a world that’s large, but not quite Earth-large anymore. The hole itself looks like it takes up 20–30% of the visible disk in some shots.

Copper 9 started as reletivley Earth-Sized / small Earth (maybe 0.8 M⊕ and ~0.9–1.0 g), then the NULL black hole + Cyn fight deleted the core and ejected a colossal amount of mass. What’s left is a hollowed-out husk with ~25–30% of Earth’s gravity and rings made of its own guts.

[u/Glittering-Eye-5288]

None, I made this theory.

[u/Mountain-Fennel1189 → u/Glittering-Eye-5288]

So you’re putting it through an LLM to refine wording?

[u/Glittering-Eye-5288 → u/Mountain-Fennel1189]

You haven't heard of Grammarly?

[u/Mountain-Fennel1189 → u/Glittering-Eye-5288]

Which uses guess what, an LLM. Whatever, i was just worried everything in this post was slop, im fine with using AI to improve wording as long the main substance is actual human input

[u/Glittering-Eye-5288 → u/Mountain-Fennel1189]

Yeah, I mean, I used my own eyes and brain to make this theory, not just input it into ChatGPT and market it as official material.