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 is in the Goldilocks zone witch is where it is not too hot and not too cold but the right temperature for life. Anything further away from the sun than the Earth is, is way below 0 degrees Celsius as mars is -250 degrees Celsius. 7 people found this useful.