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.
Scientists have discovered an Earth-mass world about four light-years away that is orbiting a red dwarf star named Proxima Centauri. The planet, dubbed Proxima b, is believed to have a temperature suitable for liquid water to exist, which means it could potentially sustain life. Proxima b is the closest exoplanet to Earth and it's 1.3 times bigger.