Why spacesuits required in space

as we all see in the movies and on the tv when scientist go out of space they wear a suit and they call spacesuit,why astronoite need spacesuit and why spacesuit has white colour ,the first space suit colour was orange and reason of bright colour like white in the space there is no air to breath and there is no air to pressure ,in space extram cold and too much dangerous radiations ,dark colour watch/ notice/ celebrate/ obey the radiation and light colour reflect the rediation and heat that the reason why spacesuite has white colour they help astronoite to servie in the space