▁average ▁distance ▁between ▁the ▁Sun ▁and ▁Earth . ▁Initial ▁observations ▁showed ▁that ▁it ▁has ▁a ▁radius ▁more ▁than ▁double ▁that ▁of ▁Earth , ▁and ▁suggested ▁a ▁higher ▁density , ▁suggesting ▁a ▁mainly ▁rock y ▁composition ▁with ▁around ▁ 5 – 2 0 % ▁ ices ▁by ▁mass . ▁For ▁comparison , ▁the ▁Earth ' s ▁o ce ans ▁represent ▁only ▁ 0 . 0 2 % ▁of ▁our ▁planet ' s ▁mass , ▁with ▁an ▁additional ▁amount ▁potentially ▁a ▁few ▁times ▁this ▁stored ▁in ▁the ▁mant le . ▁ ▁However , ▁in ▁ 2 0 1 7 , ▁more ▁careful ▁analysis ▁using ▁both ▁H AR PS ▁and ▁H I RES ▁data ▁revealed ▁that ▁Ke pler - 1 0 c ▁is ▁not ▁a ▁large ▁terrest rial ▁planet , ▁but ▁instead ▁a ▁typical ▁vol atile - rich ▁planet ▁of ▁about ▁seven ▁Earth ▁masses . ▁ ▁Disc overy ▁and ▁confirm ation ▁In ▁January ▁ 2 0 1 1 , ▁the ▁closely ▁orbit ing ▁planet ▁Ke pler - 1 0 b ▁was ▁confirmed ▁in ▁the ▁orbit ▁of ▁the ▁star ▁Ke pler - 1 0 ▁after ▁measurements ▁of ▁its ▁trans iting ▁behavior ▁( where ▁it ▁cross es ▁in ▁front ▁of ▁Ke pler - 1 0 , ▁period ically ▁dim ming ▁it ) ▁and ▁a ▁radial ▁velocity ▁effect ▁detected ▁in ▁Ke pler - 1 0 ' s ▁spectrum ▁provided ▁the ▁information ▁needed ▁to ▁prove ▁that ▁it ▁was ▁indeed ▁a ▁planet . ▁An ▁additional , ▁longer - period ▁dim ming ▁was ▁detected ▁in ▁Ke pler - 1 0 ' s