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.
'Once a cell is vitrified it can continue to survive right down to incredibly low temperatures. It just can't do much until it warms up.' More complex organisms are able to survive at lower temperatures because they are able to control the medium the cells sit in to some extent. 'Bacteria, unicellular algae and unicellular fungi â of which there are a huge amount in the world-are free-living because they don't rely on other organisms ,' Clarke explains.