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.
Ever since astronomers in the 1800s noticed markings on Mars that looked like canals, people have imagined that there could be life on the planet (Martians!). 1  Of all the planets, Mars' climate is most like Earth. 2  Our other neighbor, Venus, is hotter than humans could ever endure.3  Still, Mars is not exactly like Earth. Of all the planets, Mars' climate is most like Earth. 2  Our other neighbor, Venus, is hotter than humans could ever endure. 3  Still, Mars is not exactly like Earth. 4  The air on Mars is as thin as the atmosphere 55,000 feet above Earth, and it's almost entirely carbon dioxide. ( 5 That's what we exhale.