Recent content by superearth

IMO, using radio signals is not a requirement for life. Even in this small solar system, we can still hope to have microbes on Mars, fishes on Europa and silicon-based life on Titan. But we can hardly hope they are smart enough to find us. More on Fermi paradox.

You seem confused. Any element other than hydrogen and helium is metal, so Yes, you need metals to have "rocks". On a more relevant note, can we really rule out Pop II? They are metal poor but not metal free Pop III. Even with one in billion chance, they should have rocky planets before Pop I...