channels evidence huge life liquid much near past search surface water evidence life liquid much near networks past search surface valley water evidence life liquid much near past search surface water 1.5 au distant heat internal loss planet relatively rocky sun terrestrial diversity great lava plains planet rocky shield terrain terrestrial types volcanoes 1.5 au distant diversity great planet relatively rocky sun terrain terrestrial types craters diversity great impact planet rocky terrain terrestrial types diversity great planet rocky terrain terrestrial types diversity dunes great planet rocky terrain terrestrial types ubiquitous activity diversity great no planet plate present rocky tectonic terrain terrestrial types channels diversity great huge planet rocky terrain terrestrial types diversity features great planet rocky tectonic terrain terrestrial types diversity great networks planet rocky terrain terrestrial types valley canyons diversity great huge planet rocky terrain terrestrial types atmosphere but carbon dioxide dynamic mainly planet rocky terrestrial thin 1.5 atmosphere au but distant dynamic planet relatively rocky sun terrestrial thin atmosphere but diversity dynamic great planet rocky terrain terrestrial thin types 6800 diameter heat internal km loss planet relatively rocky small terrestrial 1.5 6800 au diameter distant km planet relatively rocky small sun terrestrial 6800 diameter diversity great km planet relatively rocky small terrain terrestrial types 6800 atmosphere but diameter dynamic km planet relatively rocky small terrestrial thin caps carbon dioxide large mainly permanent planet polar rocky seasonal small terrestrial 1.5 au caps distant large permanent planet polar relatively rocky seasonal small sun terrestrial caps diversity great large permanent planet polar rocky seasonal small terrain terrestrial types atmosphere but caps dynamic large permanent planet polar rocky seasonal small terrestrial thin 6800 caps diameter km large permanent planet polar relatively rocky seasonal small terrestrial 25.2 axial degrees earth earth-like neighbor planet rocky seasons terrestrial tilt differentiated earth interior neighbor planet rocky terrestrial earth neighbor planet rocky terrestrial earth mars neighbor planet rocky terrestrial ancient earth field magnetic neighbor planet rocky terrestrial 24.6 day earth earth-like hours neighbor planet rocky terrestrial 1.5 au distant earth neighbor planet relatively rocky sun terrestrial earth jupiter neighbor planet rocky terrestrial diversity earth great neighbor planet rocky terrain terrestrial types atmosphere but dynamic earth neighbor planet rocky terrestrial thin 6800 diameter earth km neighbor planet relatively rocky small terrestrial caps earth large neighbor permanent planet polar rocky seasonal small terrestrial 4.5 billion earth history neighbor planet rocky terrestrial year 1.88 earth neighbor period planet revolution rocky terrestrial years desert earth neighbor planet red rocky terrestrial 25.2 axial degrees differentiated earth-like interior planet rocky seasons terrestrial tilt 25.2 axial degrees earth-like planet rocky seasons terrestrial tilt 25.2 axial degrees earth-like mars planet rocky seasons terrestrial tilt 25.2 ancient axial degrees earth-like field magnetic planet rocky seasons terrestrial tilt 24.6 25.2 axial day degrees earth-like hours planet rocky seasons terrestrial tilt 1.5 25.2 au axial degrees distant earth-like planet relatively rocky seasons sun terrestrial tilt 25.2 axial degrees earth-like jupiter neighbor planet rocky seasons terrestrial tilt 25.2 axial degrees diversity earth-like great planet rocky seasons terrain terrestrial tilt types 25.2 atmosphere axial but degrees dynamic earth-like planet rocky seasons terrestrial thin tilt 25.2 6800 axial degrees diameter earth-like km planet relatively rocky seasons small terrestrial tilt 25.2 axial caps degrees earth-like large permanent planet polar rocky seasonal seasons small terrestrial tilt 25.2 4.5 axial billion degrees earth-like history planet rocky seasons terrestrial tilt year 1.88 25.2 axial degrees earth-like period planet revolution rocky seasons terrestrial tilt years 25.2 axial degrees desert earth-like planet red rocky seasons terrestrial tilt differentiated interior planet rocky terrestrial differentiated interior mars planet rocky terrestrial ancient differentiated field interior magnetic planet rocky terrestrial 24.6 day differentiated earth-like hours interior planet rocky terrestrial 1.5 au differentiated distant interior planet relatively rocky sun terrestrial differentiated interior jupiter neighbor planet rocky terrestrial differentiated diversity great interior planet rocky terrain terrestrial types atmosphere but differentiated dynamic interior planet rocky terrestrial thin 6800 diameter differentiated interior km planet relatively rocky small terrestrial caps differentiated interior large permanent planet polar rocky seasonal small terrestrial 4.5 billion differentiated history interior planet rocky terrestrial year 1.88 differentiated interior period planet revolution rocky terrestrial years desert differentiated interior planet red rocky terrestrial mars planet rocky terrestrial ancient field magnetic mars planet rocky terrestrial 24.6 day earth-like hours mars planet rocky terrestrial 1.5 au distant mars planet relatively rocky sun terrestrial jupiter mars neighbor planet rocky terrestrial diversity great mars planet rocky terrain terrestrial types atmosphere but dynamic mars planet rocky terrestrial thin 6800 diameter km mars planet relatively rocky small terrestrial caps large mars permanent planet polar rocky seasonal small terrestrial 4.5 billion history mars planet rocky terrestrial year 1.88 mars period planet revolution rocky terrestrial years desert mars planet red rocky terrestrial ancient field magnetic planet rocky terrestrial 24.6 ancient day earth-like field hours magnetic planet rocky terrestrial 1.5 ancient au distant field magnetic planet relatively rocky sun terrestrial ancient field jupiter magnetic neighbor planet rocky terrestrial ancient diversity field great magnetic planet rocky terrain terrestrial types ancient atmosphere but dynamic field magnetic planet rocky terrestrial thin 6800 ancient diameter field km magnetic planet relatively rocky small terrestrial ancient caps field large magnetic permanent planet polar rocky seasonal small terrestrial 4.5 ancient billion field history magnetic planet rocky terrestrial year 1.88 ancient field magnetic period planet revolution rocky terrestrial years ancient desert field magnetic planet red rocky terrestrial channels diversity great huge liquid much near past surface terrain types water diversity great liquid much near networks past surface terrain types valley water channels huge liquid much near networks past surface valley water 1.5 au distant extant heat internal loss possible relatively sun volcanism activity extant heat internal loss no plate possible present tectonic volcanism extant heat internal loss possible volcanism 6800 diameter extant heat internal km loss possible relatively small volcanism craters diversity great impact lava plains shield terrain types volcanoes diversity great lava plains shield terrain types volcanoes diversity dunes great lava plains shield terrain types ubiquitous volcanoes activity diversity great lava no plains plate present shield tectonic terrain types volcanoes channels diversity great huge lava plains shield terrain types volcanoes diversity features great lava plains shield tectonic terrain types volcanoes diversity great lava networks plains shield terrain types valley volcanoes canyons diversity great huge lava plains shield terrain types volcanoes 24.6 day earth-like hours planet rocky terrestrial 1.5 24.6 au day distant earth-like hours planet relatively rocky sun terrestrial 24.6 day earth-like hours jupiter neighbor planet rocky terrestrial 24.6 day diversity earth-like great hours planet rocky terrain terrestrial types 24.6 atmosphere but day dynamic earth-like hours planet rocky terrestrial thin 24.6 6800 day diameter earth-like hours km planet relatively rocky small terrestrial 24.6 caps day earth-like hours large permanent planet polar rocky seasonal small terrestrial 24.6 4.5 billion day earth-like history hours planet rocky terrestrial year 1.88 24.6 day earth-like hours period planet revolution rocky terrestrial years 24.6 day desert earth-like hours planet red rocky terrestrial craters diversity great impact terrain types craters diversity dunes great impact terrain types ubiquitous activity craters diversity great impact no plate present tectonic terrain types channels craters diversity great huge impact terrain types craters diversity features great impact tectonic terrain types craters diversity great impact networks terrain types valley canyons craters diversity great huge impact terrain types diversity dunes great terrain types ubiquitous activity diversity dunes great no plate present tectonic terrain types ubiquitous channels diversity dunes great huge terrain types ubiquitous diversity dunes features great tectonic terrain types ubiquitous diversity dunes great networks terrain types ubiquitous valley canyons diversity dunes great huge terrain types ubiquitous 1.5 au distant planet relatively rocky sun terrestrial 1.5 au distant jupiter neighbor planet relatively rocky sun terrestrial 1.5 4.5 au billion distant history planet relatively rocky sun terrestrial year 1.5 1.88 au distant period planet relatively revolution rocky sun terrestrial years 1.5 au desert distant planet red relatively rocky sun terrestrial 1.5 activity au distant heat internal loss no plate present relatively sun tectonic 1.5 au distant heat internal loss relatively sun 1.5 6800 au diameter distant heat internal km loss relatively small sun jupiter neighbor planet rocky terrestrial diversity great jupiter neighbor planet rocky terrain terrestrial types atmosphere but dynamic jupiter neighbor planet rocky terrestrial thin 6800 diameter jupiter km neighbor planet relatively rocky small terrestrial caps jupiter large neighbor permanent planet polar rocky seasonal small terrestrial 4.5 billion history jupiter neighbor planet rocky terrestrial year 1.88 jupiter neighbor period planet revolution rocky terrestrial years desert jupiter neighbor planet red rocky terrestrial 4.5 billion diversity great history planet rocky terrain terrestrial types year 1.88 diversity great period planet revolution rocky terrain terrestrial types years desert diversity great planet red rocky terrain terrestrial types activity diversity great heat internal loss no plate present tectonic terrain types activity channels diversity great huge no plate present tectonic terrain types activity diversity great networks no plate present tectonic terrain types valley channels diversity great huge networks terrain types valley activity diversity great no plate present tectonic terrain types activity diversity features great no plate present tectonic terrain types activity canyons diversity great huge no plate present tectonic terrain types activity heat internal loss no plate present tectonic 6800 activity diameter heat internal km loss no plate present relatively small tectonic atmosphere but dynamic planet rocky terrestrial thin 4.5 atmosphere billion but dynamic history planet rocky terrestrial thin year 1.88 atmosphere but dynamic period planet revolution rocky terrestrial thin years atmosphere but desert dynamic planet red rocky terrestrial thin atmosphere but caps carbon dioxide dynamic large mainly permanent polar seasonal small thin 6800 diameter km planet relatively rocky small terrestrial 4.5 6800 billion diameter history km planet relatively rocky small terrestrial year 1.88 6800 diameter km period planet relatively revolution rocky small terrestrial years 6800 desert diameter km planet red relatively rocky small terrestrial 6800 diameter heat internal km loss relatively small caps large permanent planet polar rocky seasonal small terrestrial 4.5 billion caps history large permanent planet polar rocky seasonal small terrestrial year 1.88 caps large period permanent planet polar revolution rocky seasonal small terrestrial years caps desert large permanent planet polar red rocky seasonal small terrestrial 4.5 billion history planet rocky terrestrial year 1.88 4.5 billion history period planet revolution rocky terrestrial year years 4.5 billion desert history planet red rocky terrestrial year channels huge liquid much near past surface water channels diversity great huge terrain types channels diversity features great huge tectonic terrain types canyons channels diversity great huge terrain types diversity features great tectonic terrain types diversity features great networks tectonic terrain types valley canyons diversity features great huge tectonic terrain types liquid much near networks past surface valley water diversity great networks terrain types valley canyons diversity great huge networks terrain types valley 1.88 period planet revolution rocky terrestrial years 1.88 desert period planet red revolution rocky terrestrial years canyons diversity great huge terrain types desert planet red rocky terrestrial