The impeller made out of cast material in many cases may be called rotor, also. It is cheaper to cast the radial impeller right in the support it is fitted on, which is put in motion by the gearbox from an electric motor, combustion engine or by steam driven turbine.
Earth remains the only known planet to host life, due to a unique combination of factors. However, continued monitoring of alien worlds might one day change that, by finding other planets that share these attributes or by discovering other ways that life has found to blossom in the universe.
Earth could continue to host life for at least another 1.75 billion years, as long as some disaster doesn't intervene. Earth could continue to host life for at least another 1.75 billion years, as long as some disaster doesn't intervene. Earth could continue to host life for at least another 1.75 billion years, as long as nuclear holocaust, an errant asteroid or some other disaster doesn't intervene, a new study calculates. But even without such dramatic doomsday scenarios, astronomical forces will eventually render the planet uninhabitable.