In1974,forthefirsttime,asU.S.spacecraftpassedwithin400milesofthe
planetMercury.Thenameofthespacecraftwasmariner10.Therewerenopeopleonthespacecraft,buttherewerecamerasthatcouldtakeclearpicturesfromalongdistance.Whatthepicturesshowedwasinteresting.Theyshowedthat
Mercury'ssurfacewasalotlikethesurfaceoftheMoon.ThesurfaceofMercuryisfilledwithhugeholescalledcraters.AlayeroffinedustcoversMercury.This,tooislikethedustontheMoon.ThereisnolifeoneitherMercuryortheMoon.