Here's why:
* Earth's Core: Earth's core is primarily composed of iron and nickel, but it's not solid. It has a solid inner core and a liquid outer core. The extreme pressure at the inner core causes the iron to solidify even though the temperature is extremely high.
* Other Planets: Other planets like Mars and Mercury also have cores, but they are not entirely solid metal balls. Their cores likely have a combination of solid and liquid components.
Planets with Solid Metal Cores:
The idea of a planet with a solid metal core is purely hypothetical. It's a common theme in science fiction, but it's not based on any known scientific evidence.
Key Takeaway: While the core of Earth and other planets contains metals, they are not entirely solid metal balls.
