CINXE.COM

<!DOCTYPE html> <html class="" lang="ga-GB"> <head><script type="text/javascript" src="/_static/js/bundle-playback.js?v=HxkREWBo" charset="utf-8"></script> <script type="text/javascript" src="/_static/js/wombat.js?v=txqj7nKC" charset="utf-8"></script> <script>window.RufflePlayer=window.RufflePlayer||{};window.RufflePlayer.config={"autoplay":"on","unmuteOverlay":"hidden"};</script> <script type="text/javascript" src="/_static/js/ruffle/ruffle.js"></script> <script type="text/javascript"> __wm.init("https://web.archive.org/web"); __wm.wombat("http://www.bbc.co.uk/guides/zcvtjty","20180130201953","https://web.archive.org/","web","/_static/", "1517343593"); </script> <link rel="stylesheet" type="text/css" href="/_static/css/banner-styles.css?v=S1zqJCYt" /> <link rel="stylesheet" type="text/css" href="/_static/css/iconochive.css?v=3PDvdIFv" />   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <meta name="description" content="Life on Earth originated from simple microbes 3.5 billion years ago. Is it possible that these life-forms could have originated from Mars?"/> <meta name="keywords" content="BBC, Guides"/> <title>Tomorrow's World - Are we all really Martians?</title> <meta name="viewport" content="width=device-width, initial-scale=1.0"/> <meta property="fb:admins" content="100004154058350"/>  <link rel="stylesheet" href="https://web.archive.org/web/20180130201953cs_/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/style/orb.min.css">    <script class="js-require-lib" src="https://web.archive.org/web/20180130201953js_/http://static.bbci.co.uk/frameworks/requirejs/lib.js"></script> <script type="text/javascript"> bbcRequireMap = {"jquery-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jquery/0.4.1/sharedmodules/jquery-1.7.2", "jquery-1.4":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jquery/0.4.1/sharedmodules/jquery-1.4", "jquery-1.9":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jquery/0.4.1/sharedmodules/jquery-1.9.1", "jquery-1.12":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jquery/0.4.1/sharedmodules/jquery-1.12.0.min", "jquery-2.2":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jquery/0.4.1/sharedmodules/jquery-2.2.0.min", "istats-1":"//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/nav-analytics/0.1.0-43/js/istats-1", "swfobject-2":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/swfobject/0.1.10/sharedmodules/swfobject-2", "demi-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/demi/0.10.1/sharedmodules/demi-1", "gelui-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/gelui/0.9.13/sharedmodules/gelui-1", "cssp!gelui-1/overlay":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/gelui/0.9.13/sharedmodules/gelui-1/overlay.css", "relay-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/relay/0.2.6/sharedmodules/relay-1", "clock-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/clock/0.1.9/sharedmodules/clock-1", "canvas-clock-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/clock/0.1.9/sharedmodules/canvas-clock-1", "cssp!clock-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/clock/0.1.9/sharedmodules/clock-1.css", "jssignals-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jssignals/0.3.6/modules/jssignals-1", "jcarousel-1":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/jcarousel/0.1.10/modules/jcarousel-1", "bump-3":"//web.archive.org/web/20180130201953/http://emp.bbci.co.uk/emp/bump-3/bump-3", "hammer":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/hammer", "kandlcommon/feature-detection":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlcommon/feature-detection", "kandlcommon/i18n/mediaPlayer":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlcommon/i18n/mediaPlayer", "kandlguides-vendors/echo":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/echo", "kandlguides-vendors/jquery-2":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/jquery-2", "kandlguides-vendors/playpen/common":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/playpen/common", "kandlguides-vendors/playpen/embed":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/playpen/embed", "kandlguides-vendors/playpen/freeze":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/playpen/freeze", "kandlguides-vendors/smooth-scroll":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/smooth-scroll", "kandlguides/controller/embeddedTimelines":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/controller/embeddedTimelines", "kandlguides/controller/page":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/controller/page", "cssp!kandlguides/debug/debugConsole":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/debug/debugConsole.css", "kandlguides/debug/debugConsole":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/debug/debugConsole", "kandlguides/debug/iStatsHelper":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/debug/iStatsHelper", "kandlguides/production/testHarness":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides/production/testHarness", "orientationchangeend":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/orientationchangeend", "kandlguides":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides", "kandlguides-vendors":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors"}; require({ baseUrl: 'https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/', paths: bbcRequireMap, waitSeconds: 30 }); </script> <script type="text/javascript">/*<![CDATA[*/ if (typeof bbccookies_flag === 'undefined') { bbccookies_flag = 'ON'; } showCTA_flag = true; cta_enabled = (showCTA_flag && (bbccookies_flag === 'ON')); (function(){var m="ckns_policy",q="Thu, 01 Jan 1970 00:00:00 GMT",i={ads:true,personalisation:true,performance:true,necessary:true};function c(u){if(c.cache[u]){return c.cache[u]}var t=u.split("/"),v=[""];do{v.unshift((t.join("/")||"/"));t.pop()}while(v[0]!=="/");c.cache[u]=v;return v}c.cache={};function a(u){if(a.cache[u]){return a.cache[u]}var v=u.split("."),t=[];while(v.length&&"|co.uk|com|".indexOf("|"+v.join(".")+"|")===-1){if(v.length){t.push(v.join("."))}v.shift()}c.cache[u]=t;return t}a.cache={};function s(t,y,u){var E=[""].concat(a(window.location.hostname)),B=c(window.location.pathname),D="",w,C;for(var x=0,A=E.length;x<A;x++){w=E[x];for(var v=0,z=B.length;v<z;v++){C=B[v];D=t+"="+y+";"+(w?"domain="+w+";":"")+(C?"path="+C+";":"")+(u?"expires="+u+";":"");bbccookies.set(D,true)}}}window.bbccookies={POLICY_REFRESH_DATE_MILLIS:new Date(2015,4,21,0,0,0,0).getTime(),POLICY_EXPIRY_COOKIENAME:"ckns_policy_exp",_setEverywhere:s,cookiesEnabled:function(){var t="ckns_testcookie"+Math.floor(Math.random()*100000);this.set(t+"=1");if(this.get().indexOf(t)>-1){e(t);return true}return false},get:function(){return document.cookie},getCrumb:function(t){if(!t){return null}return decodeURIComponent(document.cookie.replace(new RegExp("(?:(?:^|.*;)\\s*"+encodeURIComponent(t).replace(/[\-\.\+\*]/g,"\\$&")+"\\s*\\=\\s*([^;]*).*$)|^.*$"),"$1"))||null},policyRequiresRefresh:function(){var u=new Date();u.setHours(0);u.setMinutes(0);u.setSeconds(0);u.setMilliseconds(0);if(bbccookies.POLICY_REFRESH_DATE_MILLIS<=u.getTime()){var t=bbccookies.getCrumb(bbccookies.POLICY_EXPIRY_COOKIENAME);if(t){t=new Date(parseInt(t));t.setYear(t.getFullYear()-1);return bbccookies.POLICY_REFRESH_DATE_MILLIS>=t.getTime()}else{return true}}else{return false}},_setPolicy:function(t){return f.apply(this,arguments)},readPolicy:function(){return l.apply(this,arguments)},_deletePolicy:function(){s(m,"",q)},_isConfirmed:function(){return n()!==null},_acceptsAll:function(){var t=l();return t&&!(j(t).indexOf("0")>-1)},_getCookieName:function(){return b.apply(this,arguments)},_showPrompt:function(){var t=((!this._isConfirmed()||this.policyRequiresRefresh())&&window.cta_enabled&&this.cookiesEnabled()&&!window.bbccookies_disable);return(window.orb&&window.orb.fig)?t&&(window.orb.fig("no")||window.orb.fig("ck")):t},_getPolicy:this.readPolicy};function b(u){var t=(""+u).match(/^([^=]+)(?==)/);return(t&&t.length?t[0]:"")}function j(t){return""+(t.ads?1:0)+(t.personalisation?1:0)+(t.performance?1:0)}function f(x){if(typeof x==="undefined"){x=i}if(typeof arguments[0]==="string"){var u=arguments[0],w=arguments[1];if(u==="necessary"){w=true}x=l();x[u]=w}else{if(typeof arguments[0]==="object"){x.necessary=true}}var v=new Date();v.setYear(v.getFullYear()+1);bbccookies.set(m+"="+j(x)+";domain=bbc.co.uk;path=/;expires="+v.toUTCString()+";");bbccookies.set(m+"="+j(x)+";domain=bbc.com;path=/;expires="+v.toUTCString()+";");bbccookies.set(m+"="+j(x)+";domain=bbci.co.uk;path=/;expires="+v.toUTCString()+";");var t=new Date(v.getTime());t.setMonth(t.getMonth()+1);bbccookies.set(bbccookies.POLICY_EXPIRY_COOKIENAME+"="+v.getTime()+";domain=bbc.co.uk;path=/;expires="+t.toUTCString()+";");bbccookies.set(bbccookies.POLICY_EXPIRY_COOKIENAME+"="+v.getTime()+";domain=bbc.com;path=/;expires="+t.toUTCString()+";");bbccookies.set(bbccookies.POLICY_EXPIRY_COOKIENAME+"="+v.getTime()+";domain=bbci.co.uk;path=/;expires="+t.toUTCString()+";");return x}function o(t){if(t===null){return null}var u=t.split("");return{ads:!!+u[0],personalisation:!!+u[1],performance:!!+u[2],necessary:true}}function n(){var t=new RegExp("(?:^|; ?)"+m+"=(\\d\\d\\d)($|;)"),u=document.cookie.match(t);if(!u){return null}return u[1]}function l(t){var u=o(n());if(!u){u=i}if(t){return u[t]}else{return u}}function e(t){return document.cookie=t+"=;expires="+q+";"}var g=!(window.bbccookies_flag==="ON"&&!bbccookies._acceptsAll()&&!window.bbccookies_disable);var k={},d={"personalisation":"ckps_.+|X-AB-iplayer-.+|ACTVTYMKR|BBC_EXAMPLE_COOKIE|BBCIplayer|BBCiPlayerM|BBCIplayerSession|BBCMediaselector|BBCPostcoder|bbctravel|CGISESSID|ed|food-view|forceDesktop|h4|IMRID|locserv|MyLang|myloc|NTABS|ttduserPrefs|V5|WEATHER|BBCScienceDiscoveryPlaylist_.+|bitratePref|correctAnswerCount|genreCookie|highestQuestionScore|incorrectAnswerCount|longestStreak|MSCSProfile|programmes-oap-expanded|quickestAnswer|score|servicePanel|slowestAnswer|totalTimeForAllFormatted|v|BBCwords|score|correctAnswerCount|highestQuestionScore|hploc|BGUID|BBCWEACITY|mstouch|myway|BBCNewsCustomisation|cbbc_anim|cbeebies_snd|bbcsr_usersx|cbeebies_rd|BBC-Latest_Blogs|zh-enc|pref_loc|m|bbcEmp.+|recs-.+|_lvd2|_lvs2|tick|_fcap_CAM1|_rcc2","performance":"ckpf_.+|optimizely.*|BBCLiveStatsClick|id|_em_.+|cookies_enabled|mbox|mbox-admin|mc_.+|omniture_unique|s_.+|sc_.+|adpolicyAdDisplayFrequency|s1|ns_session|ns_cookietest|ns_ux|NO-SA|tr_pr1|gvsurvey|bbcsurvey|si_v|sa_labels|obuid|mm_.+|mmid|mmcore.+|mmpa.+","ads":"ckad_.+|rsi_segs|c","necessary":"ckns_.+|BBC-UID|blq\\.dPref|SSO2-UID|BBC-H2-User|rmRpDetectReal|bbcComSurvey|IDENTITY_ENV|IDENTITY|IDENTITY-HTTPS|IDENTITY_SESSION|BBCCOMMENTSMODULESESSID|bbcBump.+|IVOTE_VOTE_HISTORY|pulse|BBCPG|BBCPGstat|ecos\\.dt"};function r(){var x=document.cookie.replace(/; +/g,";").split(";"),u,v=[];for(var w=0,t=x.length;w<t;w++){u=x[w];v.push(bbccookies._getCookieName(u))}return v}function h(w){var v=JSON.stringify(w);if(typeof(k[v])!=="undefined"){return k[v]}var u="";for(var t in w){if(w.hasOwnProperty(t)&&d[t]){if(w[t]===true){u+=(u?"|":"")+d[t]}}}k[v]=new RegExp("^("+(u?u:".*")+")$","i");return k[v]}bbccookies.getPolicyExpiryDateTime=function(){return bbccookies.POLICY_EXPIRY_COOKIENAME};bbccookies.purge=function(){var u=bbccookies.readPolicy(),w=r(),x;for(var v=0,t=w.length;v<t;v++){if(!bbccookies.isAllowed(w[v],u)){x=new Date();x.setTime(0);x=x.toUTCString();s(w[v],"deleted",x)}}};function p(){if(g){return}bbccookies.purge();contentLoaded(window,bbccookies.purge);if(window.addEventListener){window.addEventListener("beforeunload",bbccookies.purge,false)}else{if(window.attachEvent){window.attachEvent("onbeforeunload",bbccookies.purge)}else{window.onbeforeunload=bbccookies.purge}}}bbccookies.set=function(u,t){if(g){return document.cookie=u}var v=bbccookies._getCookieName(u);if(t||bbccookies.isAllowed(v)){return document.cookie=u}return null};bbccookies.isAllowed=function(v){var u=bbccookies.readPolicy();var t=h(u);return t.test(v)};p()})(); /*! * contentloaded.js * * Author: Diego Perini (diego.perini at gmail.com) * Summary: cross-browser wrapper for DOMContentLoaded * Updated: 20101020 * License: MIT * Version: 1.2 * * URL: * http://javascript.nwbox.com/ContentLoaded/ * http://javascript.nwbox.com/ContentLoaded/MIT-LICENSE * */ function contentLoaded(d,i){var c=false,h=true,k=d.document,j=k.documentElement,a=k.addEventListener,n=a?"addEventListener":"attachEvent",l=a?"removeEventListener":"detachEvent",b=a?"":"on",m=function(o){if(o.type==="readystatechange"&&k.readyState!="complete"){return}(o.type==="load"?d:k)[l](b+o.type,m,false);if(!c&&(c=true)){i.call(d,o.type||o)}},g=function(){try{j.doScroll("left")}catch(o){setTimeout(g,50);return}m("poll")};if(k.readyState==="complete"){i.call(d,"lazy")}else{if(!a&&j.doScroll){try{h=!d.frameElement}catch(f){}if(h){g()}}k[n](b+"DOMContentLoaded",m,false);k[n](b+"readystatechange",m,false);d[n](b+"load",m,false)}}if(typeof(require)==="function"&&!require.defined("orb/cookies")){define("orb/cookies",function(){return window.bbccookies})}; /*]]>*/</script> <script type="text/javascript"> define('orb/cookies', function() { return window.bbccookies; }); </script> <script type="text/javascript">/*<![CDATA[*/ (function(){window.orb={};window.orb.figState={ad:0,ap:0,ck:1,eu:1,mb:0,tb:0,uk:1,df:1};window.orb.fig=function(a){return(arguments.length)?window.orb.figState[a]:window.orb.figState};window.orb.fig.device={};window.orb.fig.geo={};window.orb.fig.user={};window.orb.fig.isDefault=function(){return window.orb.fig("df")};window.orb.fig.device.isTablet=function(){return window.orb.fig("tb")};window.orb.fig.device.isMobile=function(){return window.orb.fig("mb")};window.orb.fig.geo.isUK=function(){return window.orb.fig("uk")};window.orb.fig.geo.isEU=function(){return window.orb.fig("eu")};window.fig=window.fig||{};window.fig.manager={include:function(e){e=e||window;var g=false;var j=e.document,k=j.cookie,i=k.match(/(?:^|; ?)ckns_orb_fig=([^;]+)/),h;if(i){i=this.deserialise(decodeURIComponent(RegExp.$1));this.setFig(e,i)}if(window.fig.async&&typeof JSON!="undefined"){var b=(document.cookie.match("(^|; )ckns_orb_cachedfig=([^;]*)")||0)[2];h=b?JSON.parse(b):null;if(h){this.setFig(e,h);g=true}}var a="https://web.archive.org/web/20180130201953/https://fig.bbc.co.uk/frameworks/fig/1/fig.js";if(g){j.write('<script src="'+a+'" async><'+"/script>")}else{j.write('<script src="'+a+'"><'+"/script>")}},confirm:function(a){return true},setFig:function(a,b){(function(){a.orb=a.orb||{};a.orb.figState=b})()},deserialise:function(b){var a={};b.replace(/([a-z]{2}):([0-9]+)/g,function(){a[RegExp.$1]=+RegExp.$2});return a}}})();fig.manager.include();/*]]>*/</script>  <script type="text/javascript">window.bbcFlagpoles_istats="ON",require.config({paths:{"istats-1":"//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/nav-analytics/0.1.0-89/js/istats-1","megavolt-client":"//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/nav-analytics/0.1.0-89/js/megavolt-client"},config:{"megavolt-client":{baseUrl:"https://web.archive.org/web/20180130201953/https://mvt.api.bbc.com"}}}),require(["istats-1","orb/cookies"],function(e,t){if(t.isAllowed("s1")){e.addCollector({name:"default",url:"https://web.archive.org/web/20180130201953/https://sa.bbc.co.uk/bbc/bbc/s",separator:"&"});var a="kl.iwonder.guides.knowledge_learning.tomorrows_world.are_we_all_really_martians.zcvtjty.page";e.setCountername(a),window.istats_countername&&e.setCountername(window.istats_countername),e.addLabels("ml_name=webmodule&ml_version=89")}});</script> <script type="text/javascript">/*<![CDATA[*/ window.bbcFlagpoles_istats = 'ON'; window.orb = window.orb || {}; if (typeof bbccookies !== 'undefined' && bbccookies.isAllowed('s1')) { var istatsTrackingUrl = '//web.archive.org/web/20180130201953/http://sa.bbc.co.uk/bbc/bbc/s?name=kl.iwonder.guides.knowledge_learning.tomorrows_world.are_we_all_really_martians.zcvtjty.page&page_language=en-GB&page_type=guides&by_nation=eng&clip_count=1&step_max=2&hero_connection=false&first_published_date=2017-08-25T15%3A03%3A44.005964Z&pal_route=guides&app_type=responsive&language=ga-GB&pal_webapp=kandlguides&prod_name=guides&app_name=guides'; require(['istats-1'], function (istats) { var counterName = (window.istats_countername) ? window.istats_countername : istatsTrackingUrl.match(/[\?&]name=([^&]*)/i)[1]; istats.setCountername(counterName); istats.addLabels('page_language=en-GB&page_type=guides&by_nation=eng&clip_count=1&step_max=2&hero_connection=false&first_published_date=2017-08-25T15%3A03%3A44.005964Z&pal_route=guides&app_type=responsive&language=ga-GB&pal_webapp=kandlguides&prod_name=guides&app_name=guides'); var c = (document.cookie.match(/\bckns_policy=(\d\d\d)/) || []).pop() || ''; istats.addLabels({ 'blq_s': '4d', 'blq_r': '2.7', 'blq_v': 'default', 'blq_e': 'pal', 'bbc_mc': (c ? 'ad' + c.charAt(0) + 'ps' + c.charAt(1) + 'pf' + c.charAt(2) : 'not_set') } ); }); } /*]]>*/</script> <script type="text/javascript">/*<![CDATA[*/ (function(undefined){if(!window.bbc){window.bbc={}}var ROLLING_PERIOD_DAYS=30;window.bbc.Mandolin=function(id,segments,opts){var now=new Date().getTime(),storedItem,DEFAULT_START=now,DEFAULT_RATE=1,COOKIE_NAME="ckpf_mandolin";opts=opts||{};this._id=id;this._segmentSet=segments;this._store=new window.window.bbc.Mandolin.Storage(COOKIE_NAME);this._opts=opts;this._rate=(opts.rate!==undefined)?+opts.rate:DEFAULT_RATE;this._startTs=(opts.start!==undefined)?new Date(opts.start).getTime():new Date(DEFAULT_START).getTime();this._endTs=(opts.end!==undefined)?new Date(opts.end).getTime():daysFromNow(ROLLING_PERIOD_DAYS);this._signupEndTs=(opts.signupEnd!==undefined)?new Date(opts.signupEnd).getTime():this._endTs;this._segment=null;if(typeof id!=="string"){throw new Error("Invalid Argument: id must be defined and be a string")}if(Object.prototype.toString.call(segments)!=="[object Array]"){throw new Error("Invalid Argument: Segments are required.")}if(opts.rate!==undefined&&(opts.rate<0||opts.rate>1)){throw new Error("Invalid Argument: Rate must be between 0 and 1.")}if(this._startTs>this._endTs){throw new Error("Invalid Argument: end date must occur after start date.")}if(!(this._startTs<this._signupEndTs&&this._signupEndTs<=this._endTs)){throw new Error("Invalid Argument: SignupEnd must be between start and end date")}removeExpired.call(this,now);var overrides=window.bbccookies.get().match(/ckns_mandolin_setSegments=([^;]+)/);if(overrides!==null){eval("overrides = "+decodeURIComponent(RegExp.$1)+";");if(overrides[this._id]&&this._segmentSet.indexOf(overrides[this._id])==-1){throw new Error("Invalid Override: overridden segment should exist in segments array")}}if(overrides!==null&&overrides[this._id]){this._segment=overrides[this._id]}else{if((storedItem=this._store.getItem(this._id))){this._segment=storedItem.segment}else{if(this._startTs<=now&&now<this._signupEndTs&&now<=this._endTs&&this._store.isEnabled()===true){this._segment=pick(segments,this._rate);if(opts.end===undefined){this._store.setItem(this._id,{segment:this._segment})}else{this._store.setItem(this._id,{segment:this._segment,end:this._endTs})}log.call(this,"mandolin_segment")}}}log.call(this,"mandolin_view")};window.bbc.Mandolin.prototype.getSegment=function(){return this._segment};function log(actionType,params){var that=this;require(["istats-1"],function(istats){istats.log(actionType,that._id+":"+that._segment,params?params:{})})}function removeExpired(expires){var items=this._store.getItems(),expiresInt=+expires;for(var key in items){if(items[key].end!==undefined&&+items[key].end<expiresInt){this._store.removeItem(key)}}}function getLastExpirationDate(data){var winner=0,rollingExpire=daysFromNow(ROLLING_PERIOD_DAYS);for(var key in data){if(data[key].end===undefined&&rollingExpire>winner){winner=rollingExpire}else{if(+data[key].end>winner){winner=+data[key].end}}}return(winner)?new Date(winner):new Date(rollingExpire)}window.bbc.Mandolin.prototype.log=function(params){log.call(this,"mandolin_log",params)};window.bbc.Mandolin.prototype.convert=function(params){log.call(this,"mandolin_convert",params);this.convert=function(){}};function daysFromNow(n){var endDate;endDate=new Date().getTime()+(n*60*60*24)*1000;return endDate}function pick(segments,rate){var picked,min=0,max=segments.length-1;if(typeof rate==="number"&&Math.random()>rate){return null}do{picked=Math.floor(Math.random()*(max-min+1))+min}while(picked>max);return segments[picked]}window.bbc.Mandolin.Storage=function(name){validateCookieName(name);this._cookieName=name;this._isEnabled=(bbccookies.isAllowed(this._cookieName)===true&&bbccookies.cookiesEnabled()===true)};window.bbc.Mandolin.Storage.prototype.setItem=function(key,value){var storeData=this.getItems();storeData[key]=value;this.save(storeData);return value};window.bbc.Mandolin.Storage.prototype.isEnabled=function(){return this._isEnabled};window.bbc.Mandolin.Storage.prototype.getItem=function(key){var storeData=this.getItems();return storeData[key]};window.bbc.Mandolin.Storage.prototype.removeItem=function(key){var storeData=this.getItems();delete storeData[key];this.save(storeData)};window.bbc.Mandolin.Storage.prototype.getItems=function(){return deserialise(this.readCookie(this._cookieName)||"")};window.bbc.Mandolin.Storage.prototype.save=function(data){window.bbccookies.set(this._cookieName+"="+encodeURIComponent(serialise(data))+"; expires="+getLastExpirationDate(data).toUTCString()+";")};window.bbc.Mandolin.Storage.prototype.readCookie=function(name){var nameEq=name+"=",ca=window.bbccookies.get().split("; "),i,c;validateCookieName(name);for(i=0;i<ca.length;i++){c=ca[i];if(c.indexOf(nameEq)===0){return decodeURIComponent(c.substring(nameEq.length,c.length))}}return null};function serialise(o){var str="";for(var p in o){if(o.hasOwnProperty(p)){str+='"'+p+'"'+":"+(typeof o[p]==="object"?(o[p]===null?"null":"{"+serialise(o[p])+"}"):'"'+o[p].toString()+'"')+","}}return str.replace(/,\}/g,"}").replace(/,$/g,"")}function deserialise(str){var o;str="{"+str+"}";if(!validateSerialisation(str)){throw"Invalid input provided for deserialisation."}eval("o = "+str);return o}var validateSerialisation=(function(){var OBJECT_TOKEN="<Object>",ESCAPED_CHAR='"\\n\\r\\u2028\\u2029\\u000A\\u000D\\u005C',ALLOWED_CHAR="([^"+ESCAPED_CHAR+"]|\\\\["+ESCAPED_CHAR+"])",KEY='"'+ALLOWED_CHAR+'+"',VALUE='(null|"'+ALLOWED_CHAR+'*"|'+OBJECT_TOKEN+")",KEY_VALUE=KEY+":"+VALUE,KEY_VALUE_SEQUENCE="("+KEY_VALUE+",)*"+KEY_VALUE,OBJECT_LITERAL="({}|{"+KEY_VALUE_SEQUENCE+"})",objectPattern=new RegExp(OBJECT_LITERAL,"g");return function(str){if(str.indexOf(OBJECT_TOKEN)!==-1){return false}while(str.match(objectPattern)){str=str.replace(objectPattern,OBJECT_TOKEN)}return str===OBJECT_TOKEN}})();function validateCookieName(name){if(name.match(/ ,;/)){throw"Illegal name provided, must be valid in browser cookie."}}})(); /*]]>*/</script> <script type="text/javascript"> document.documentElement.className += (document.documentElement.className? ' ' : '') + 'orb-js'; fig.manager.confirm(); </script> <script src="https://web.archive.org/web/20180130201953js_/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/script/orb/api.min.js"></script> <script src="https://web.archive.org/web/20180130201953js_/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/script/orb/font.min.js"></script> <script type="text/javascript"> var blq = { environment: function() { return 'live'; } } </script> <script type="text/javascript"> /*<![CDATA[*/ function oqsSurveyManager(w, flag) { if (flag !== 'OFF' && (w.orb.fig("no") || w.orb.fig("uk"))) { w.document.write('<script type="text/javascript" src="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/script/vendor/edr.min.js"><'+'/script>'); } } oqsSurveyManager(window, 'ON'); /*]]>*/ </script> <link rel="canonical" href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/guides/zcvtjty"/>  <link rel="stylesheet" media="screen" href="https://web.archive.org/web/20180130201953cs_/http://static.bbci.co.uk/kandlguides/4.22.32.7202/style/compiled/branding/colour-palette-15.css"/>   <meta http-equiv="X-UA-Compatible" content="IE=Edge"/> <meta property="og:title" content="Are we all really Martians?"><meta property="og:type" content="article"><meta property="og:site_name" content="BBC Guides"><meta property="og:image" content="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/208x208/p05d9ybn.jpg"><meta property="og:url" content="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/guides/zcvtjty"><meta name="twitter:card" content="summary_large_image"><meta name="twitter:description" content="Life on Earth originated from simple microbes 3.5 billion years ago. Is it possible that these life-forms could have originated from Mars?"><meta name="twitter:image:src" content="http://ichef.bbci.co.uk/images/ic/288x162/p05d9ybn.jpg"><meta name="twitter:site" content="@BBCiWonder"> <script> require(['istats-1'], function (istats) { istats.setSite('tomorrows-world'); }); </script>  <script type="text/javascript"> /*<![CDATA[*/ var _sf_startpt = (new Date()).getTime(); /*]]>*/ </script><style type="text/css">.bbccom_display_none{display:none;}</style><script type="text/javascript"> /*<![CDATA[*/ var bbcdotcomConfig, googletag = googletag || {}; googletag.cmd = googletag.cmd || []; var bbcdotcom = false; (function(){ if(typeof require !== 'undefined') { require({ paths:{ "bbcdotcom":"https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/script" } }); } })(); /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ var bbcdotcom = { adverts: { keyValues: { set: function() {} } }, advert: { write: function () {}, show: function () {}, isActive: function () { return false; }, layout: function() { return { reset: function() {} } } }, config: { init: function() {}, isActive: function() {}, setSections: function() {}, isAdsEnabled: function() {}, setAdsEnabled: function() {}, isAnalyticsEnabled: function() {}, setAnalyticsEnabled: function() {}, setAssetPrefix: function() {}, setVersion: function () {}, setJsPrefix: function() {}, setSwfPrefix: function() {}, setCssPrefix: function() {}, setConfig: function() {}, getAssetPrefix: function() {}, getJsPrefix: function () {}, getSwfPrefix: function () {}, getCssPrefix: function () {} }, survey: { init: function(){ return false; } }, data: {}, init: function() {}, objects: function(str) { return false; }, locale: { set: function() {}, get: function() {} }, setAdKeyValue: function() {}, utils: { addEvent: function() {}, addHtmlTagClass: function() {}, log: function () {} }, addLoadEvent: function() {} }; /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function(){ if (typeof orb !== 'undefined' && typeof orb.fig === 'function') { if (orb.fig('ad') && orb.fig('uk') == 0) { bbcdotcom.data = { ads: (orb.fig('ad') ? 1 : 0), stats: (orb.fig('uk') == 0 ? 1 : 0), statsProvider: orb.fig('ap') }; } } else { document.write('<script type="text/javascript" src="'+('https:' == document.location.protocol ? 'https://web.archive.org/web/20180130201953/https://www.bbc.com' : 'https://web.archive.org/web/20180130201953/http://tps.bbc.com')+'/wwscripts/data">\x3C/script>'); } })(); /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function(){ if (typeof orb === 'undefined' || typeof orb.fig !== 'function') { bbcdotcom.data = { ads: bbcdotcom.data.a, stats: bbcdotcom.data.b, statsProvider: bbcdotcom.data.c }; } if (bbcdotcom.data.ads == 1) { document.write('<script type="text/javascript" src="'+('https:' == document.location.protocol ? 'https://web.archive.org/web/20180130201953/https://www.bbc.com' : 'https://web.archive.org/web/20180130201953/http://www.bbc.com')+'/wwscripts/flag">\x3C/script>'); } })(); /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function(){ if (window.bbcdotcom && (typeof bbcdotcom.flag == 'undefined' || (typeof bbcdotcom.data.ads !== 'undefined' && bbcdotcom.flag.a != 1))) { bbcdotcom.data.ads = 0; } if (/[?|&]ads/.test(window.location.href) || /(^|; )ads=on; /.test(document.cookie) || /; ads=on(; |$)/.test(document.cookie)) { bbcdotcom.data.ads = 1; bbcdotcom.data.stats = 1; } if (window.bbcdotcom && (bbcdotcom.data.ads == 1 || bbcdotcom.data.stats == 1)) { bbcdotcom.assetPrefix = "https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/"; if (/(sandbox|int)(.dev)*.bbc.co*/.test(window.location.href) || /[?|&]ads-debug/.test(window.location.href) || document.cookie.indexOf('ads-debug=') !== -1) { document.write('<link rel="stylesheet" type="text/css" href="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/style/dist/bbcdotcom.dev.css" />'); } else { document.write('<link rel="stylesheet" type="text/css" href="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/style/dist/bbcdotcom.css" />'); } (function() { var useSSL = 'https:' == document.location.protocol; var src = (useSSL ? 'https:' : 'http:') + '//web.archive.org/web/20180130201953/http://www.googletagservices.com/tag/js/gpt.js'; document.write('<scr' + 'ipt src="' + src + '">\x3C/script>'); })(); if (/(sandbox|int)(.dev)*.bbc.co*/.test(window.location.href) || /[?|&]ads-debug/.test(window.location.href) || document.cookie.indexOf('ads-debug=') !== -1) { document.write('<script type="text/javascript" src="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/script/dist/bbcdotcom.dev.js">\x3C/script>'); } else { document.write('<script type="text/javascript" src="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/script/dist/bbcdotcom.js">\x3C/script>'); } } })(); /*]]>*/ </script><script type="text/javascript"> if (window.bbcdotcom && bbcdotcom.data.stats == 1) { document.write('<link rel="dns-prefetch" href="//web.archive.org/web/20180130201953/http://secure-us.imrworldwide.com/">'); document.write('<link rel="dns-prefetch" href="//web.archive.org/web/20180130201953/http://me-cdn.effectivemeasure.net/">'); document.write('<link rel="dns-prefetch" href="//web.archive.org/web/20180130201953/http://ssc.api.bbc.com/">'); } if (window.bbcdotcom && bbcdotcom.data.ads == 1) { document.write('<link rel="dns-prefetch" href="//web.archive.org/web/20180130201953/http://www.googletagservices.com/">'); } </script><script type="text/javascript"> if (window.bbcdotcom && bbcdotcom.data.ads == 1) { document.write('<meta name="google-site-verification" content="auTeTTwSt_KBY_4iDoR00Lwb7-qzx1IgzJy6ztaWgEI" />'); } </script><script type="text/javascript"> /*<![CDATA[*/ (function(){ if (window.bbcdotcom && (bbcdotcom.data.ads == 1 || bbcdotcom.data.stats == 1)) { bbcdotcomConfig = {"adFormat":"standard","adKeyword":"","adMode":"smart","adsEnabled":true,"appAnalyticsSections":"","asyncEnabled":false,"disableInitialLoad":false,"advertInfoPageUrl":"https:\/\/web.archive.org\/web\/20180130201953\/http:\/\/www.bbc.com\/privacy\/cookies\/international\/","advertisementText":"Advertisement","analyticsEnabled":true,"appName":"kandlguides","assetPrefix":"https:\/\/web.archive.org\/web\/20180130201953\/http:\/\/static.bbci.co.uk\/bbcdotcom\/1.73.0\/","customAdParams":[],"customStatsParams":[],"headline":"","id":"","inAssociationWithText":"in association with","keywords":"","language":"","orbTransitional":false,"outbrainEnabled":true,"outbrainSportEnabled":true,"adsenseEnabled":true,"adsportappEnabled":true,"lotameEnabled":true,"sherlockEnabled":false,"platinumEnabled":true,"tlNewsIndexEnabled":false,"tlNewsStoryEnabled":false,"tlNewsFpEnabled":false,"winterOlympicsEnabled":false,"palEnv":"live","productName":"","sections":[],"comScoreEnabled":true,"comscoreSite":"bbc","comscoreID":"19293874","comscorePageName":"","slots":"","sponsoredByText":"is sponsored by","adsByGoogleText":"Ads by Google","summary":"","type":"","features":{"testfeature":{"name":"testfeature","envs":["sandbox","int","test"],"on":true,"options":{},"override":null},"lxadverts":{"name":"lxadverts","envs":[],"on":true,"options":{},"override":null}},"staticBase":"\/bbcdotcom","staticHost":"https:\/\/web.archive.org\/web\/20180130201953\/http:\/\/static.bbci.co.uk","staticVersion":"1.73.0","staticPrefix":"https:\/\/web.archive.org\/web\/20180130201953\/http:\/\/static.bbci.co.uk\/bbcdotcom\/1.73.0","dataHttp":"tps.bbc.com","dataHttps":"www.bbc.com","flagHttp":"www.bbc.co.uk","flagHttps":"www.bbc.co.uk","analyticsHttp":"sa.bbc.com","analyticsHttps":"ssa.bbc.com"}; bbcdotcom.config.init(bbcdotcomConfig, bbcdotcom.data, window.location, window.document); bbcdotcom.config.setAssetPrefix("https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/bbcdotcom/1.73.0/"); bbcdotcom.config.setVersion("1.73.0"); document.write(''); document.write(''); document.write(''); if (/[?|&]ex-dp/.test(window.location.href) || document.cookie.indexOf('ex-dp=') !== -1) { bbcdotcom.utils.addHtmlTagClass('bbcdotcom-ex-dp'); } } })(); /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function() { window.bbcdotcom.head = true; }()); /*]]>*/ </script>  <script type="text/javascript"> // Globally available search context window.SEARCHBOX={"variant":"default","locale":"ga","navSearchboxStaticPrefix":"//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/searchbox/1.0.0-136","searchboxAppStaticPrefix":"//web.archive.org/web/20180130201953/http://search.files.bbci.co.uk/searchbox-app/1.0.19","searchFormHtml":"<div tabindex=\"-1\" data-reactid=\".jval9y49og\" data-react-checksum=\"1886463233\"><div data-reactid=\".jval9y49og.0\"><section class=\"se-searchbox-panel\" data-reactid=\".jval9y49og.0.0\"><div class=\"se-g-wrap\" data-reactid=\".jval9y49og.0.0.0\"><div class=\"se-g-layout\" data-reactid=\".jval9y49og.0.0.0.0\"><div class=\"se-g-layout__item se-searchbox-title\" aria-hidden=\"true\" data-reactid=\".jval9y49og.0.0.0.0.0\">search</div><div class=\"se-g-layout__item se-searchbox\" data-reactid=\".jval9y49og.0.0.0.0.1\"><form accept-charset=\"utf-8\" id=\"searchboxDrawerForm\" method=\"get\" action=\"https://search.bbc.co.uk/search\" data-reactid=\".jval9y49og.0.0.0.0.1.0\"><label class=\"se-searchbox__input\" for=\"se-searchbox-input-field\" data-reactid=\".jval9y49og.0.0.0.0.1.0.0\"><span class=\"se-sr-only\" data-reactid=\".jval9y49og.0.0.0.0.1.0.0.0\">Search Term</span><input name=\"q\" type=\"text\" value=\"\" id=\"se-searchbox-input-field\" class=\"se-searchbox__input__field\" maxlength=\"512\" autocomplete=\"off\" autocorrect=\"off\" autocapitalize=\"off\" spellcheck=\"false\" tabindex=\"0\" data-reactid=\".jval9y49og.0.0.0.0.1.0.0.1\"/></label><input type=\"hidden\" name=\"scope\" value=\"\" data-reactid=\".jval9y49og.0.0.0.0.1.0.2\"/><button type=\"submit\" class=\"se-searchbox__submit\" tabindex=\"0\" data-reactid=\".jval9y49og.0.0.0.0.1.0.3\">Search</button><button type=\"button\" class=\"se-searchbox__clear se-searchbox__clear--visible\" tabindex=\"0\" data-reactid=\".jval9y49og.0.0.0.0.1.0.4\">Close</button></form></div></div></div></section><div aria-live=\"polite\" aria-atomic=\"true\" class=\"se-suggestions-container\" data-reactid=\".jval9y49og.0.1\"><section class=\"se-g-wrap\" data-reactid=\".jval9y49og.0.1.0\"></section></div></div></div>","searchScopePlaceholder":"","searchScopeParam":"","searchScopeTemplate":"","searchPlaceholderWrapperStart":"","searchPlaceholderWrapperEnd":""}; window.SEARCHBOX.suppress = false; window.SEARCHBOX.searchScope = SEARCHBOX.searchScopeTemplate.split('-')[0]; </script> <link rel="stylesheet" href="//web.archive.org/web/20180130201953cs_/http://nav.files.bbci.co.uk/searchbox/1.0.0-136/css/main.css">    <link rel="stylesheet" href="//web.archive.org/web/20180130201953cs_/http://static.bbc.co.uk/id/0.37.24/style/id-cta.css"/> <link rel="stylesheet" href="//web.archive.org/web/20180130201953cs_/http://static.bbc.co.uk/id/0.37.24/style/id-cta-v5.css"/>  <script type="text/javascript"> /* <![CDATA[ */ var map = {}; if (typeof(map['jssignals-1']) == 'undefined') { map['jssignals-1'] = 'https://web.archive.org/web/20180130201953/https://static.bbc.co.uk/frameworks/jssignals/0.3.6/modules/jssignals-1'; } require({paths: map}); /* ]]> */ </script> <script src="//web.archive.org/web/20180130201953js_/http://static.bbc.co.uk/id/0.37.24/modules/idcta/dist/idcta-1.min.js"></script> <script type="text/javascript"> (function () { if (!window.require) { throw new Error('idcta: could not find require module'); } if(typeof(map) == 'undefined') { var map = {}; } if(!!document.createElementNS && !!document.createElementNS('http://www.w3.org/2000/svg', "svg").createSVGRect) { document.documentElement.className += ' id-svg'; } var ptrt = RegExp("[\\?&]ptrt=([^&#]*)").exec(document.location.href); var ENDPOINT_URL = '//' + ((window.location.protocol == "https:") ? ('ssl.bbc.co.uk').replace("www.", "ssl.") : ('ssl.bbc.co.uk').replace("ssl.", "www.")); var ENDPOINT_CONFIG = ('/idcta/config?callback&locale=ga-GB&ptrt=' + encodeURI((ptrt ? ptrt[1] : document.location.href))).replace(/\&/g, '&'); var ENDPOINT_TRANSLATIONS = '/idcta/translations?callback&locale=ga-GB'; map['idapp-1'] = '//web.archive.org/web/20180130201953/http://static.bbc.co.uk/idapp/0.72.58/modules/idapp/idapp-1'; map['idcta'] = '//web.archive.org/web/20180130201953/http://static.bbc.co.uk/id/0.37.24/modules/idcta'; map['idcta/config'] = [ENDPOINT_URL + ENDPOINT_CONFIG, '//web.archive.org/web/20180130201953/http://static.bbc.co.uk/id/0.37.24/modules/idcta/fallbackConfig']; map['idcta/translations'] = [ENDPOINT_URL + ENDPOINT_TRANSLATIONS, '//web.archive.org/web/20180130201953/http://static.bbc.co.uk/id/0.37.24/modules/idcta/fallbackTranslations']; require({paths: map}); /* * Temporary code * To be removed when old id-statusbar-config is no longer supported */ define('id-statusbar-config', ['idcta/id-config'], function(conf) { return conf; }); define('idcta/id-statusbar-config', ['idcta/id-config'], function(conf) { return conf; }); })(); </script> <link rel="stylesheet" href="//web.archive.org/web/20180130201953cs_/http://mybbc.files.bbci.co.uk/notification-ui/3.8.4/css/main.min.css"/> <script> // Start Chartbeat timer - needs to be before shiv var _sf_startpt=(new Date()).getTime(); </script>  <script> define("assetPrefix", "https:\/\/web.archive.org\/web\/20180130201953\/http:\/\/static.bbci.co.uk\/kandlguides\/4.22.32.7202\/"); function cutsMustard(){ return ('querySelector' in document && 'localStorage' in window && 'addEventListener' in window); } var htmlElement = document.getElementsByTagName('html')[0], supportClass = ' js'; if (cutsMustard()) { supportClass += ' k-cuts-mustard'; } htmlElement.className += supportClass; if (window.bbcdotcom && bbcdotcom.init) { bbcdotcom.init({adsToDisplay:['leaderboard', 'mpu']}); } </script> </head> <body> <div id="bbccom_interstitial_ad" class="bbccom_display_none"></div><div id="bbccom_interstitial" class="bbccom_display_none"><script type="text/javascript"> /*<![CDATA[*/ (function() { if (window.bbcdotcom && bbcdotcom.config.isActive('ads')) { googletag.cmd.push(function() { googletag.display('bbccom_interstitial'); }); } }()); /*]]>*/ </script></div><div id="bbccom_wallpaper_ad" class="bbccom_display_none"></div><div id="bbccom_wallpaper" class="bbccom_display_none"><script type="text/javascript"> /*<![CDATA[*/ (function() { var wallpaper; if (window.bbcdotcom && bbcdotcom.config.isActive('ads')) { if (bbcdotcom.config.isAsync()) { googletag.cmd.push(function() { googletag.display('bbccom_wallpaper'); }); } else if (typeof googletag !== "undefined" && typeof googletag.display === "function") { googletag.display("wallpaper"); } wallpaper = bbcdotcom.adverts.adRegister.getAd('wallpaper'); } }()); /*]]>*/ </script></div><script type="text/javascript"> /*<![CDATA[*/ (function() { if (window.bbcdotcom && bbcdotcom.config.isActive('ads')) { document.write(unescape('%3Cscript id="gnlAdsEnabled" class="bbccom_display_none"%3E%3C/script%3E')); } if (window.bbcdotcom && bbcdotcom.config.isActive('analytics')) { document.write(unescape('%3Cscript id="gnlAnalyticsEnabled" class="bbccom_display_none"%3E%3C/script%3E')); } }()); /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function() { window.bbcdotcom.bodyFirst = true; }()); /*]]>*/ </script> <div id="blq-global"> <div id="blq-pre-mast"> </div> </div> <script type="text/html" id="blq-bbccookies-tmpl"><![CDATA[ <section> <div id="bbccookies" class="bbccookies-banner orb-banner-wrapper bbccookies-d"> <div id="bbccookies-prompt" class="orb-banner b-g-p b-r b-f"> <h2 class="orb-banner-title"> Fian??in ar l??ithre??n gr??as??in an BBC </h2> <p class="orb-banner-content" dir="ltr"> T?? a pholasa?? fian??n nuashonraithe ag an BBC. ??s??idimid fian??in lena chinnti?? go dtugaimid an t-eisp??ireas is fearr duit ar ??r su??omh gr??as??in. ??ir??tear leis seo fian??in ?? shu??omhanna gr??as??in me??in sh??isialta tr???? p??irt?? m?? th??ann t?? chuig leathanach ar a bhfuil ??bhar leabaithe ?? mhe??in sh??isialta. D'fh??adfadh fian??in tr???? p??irt?? den chine??l seo an ??s??id a bhaineann t?? as su??omh gr??as??in BBC a rian??. M?? leanann t?? ort gan do chuid socruithe a athr??, glacfaimid leis go bhfuil t?? s??sta gach fian??n at?? ar shu??omh gr??as??in BBC a fh??il. Is f??idir, ??fach, do chuid socruithe fian??n a athr?? am ar bith. </p> <ul class="orb-banner-options"> <li id="bbccookies-continue"> <button type="button" id="bbccookies-continue-button">Lean ar aghaidh</button> </li> <li id="bbccookies-settings"> <a href="/privacy/cookies/managing/cookie-settings.html">Athraigh Socruithe</a> </li> <li id="bbccookies-more"><a href="/privacy/cookies/bbc">Foghlaim n??os m??</a></li></ul> </div> </div> </section> ]]></script> <script type="text/javascript">/*<![CDATA[*/ (function(){if(bbccookies._showPrompt()){var g=document,b=g.getElementById("blq-pre-mast"),e=g.getElementById("blq-bbccookies-tmpl"),a,f;if(b&&g.createElement){a=g.createElement("div");f=e.innerHTML;f=f.replace("<"+"![CDATA[","").replace("]]"+">","");a.innerHTML=f;b.appendChild(a);blqCookieContinueButton=g.getElementById("bbccookies-continue-button");blqCookieContinueButton.onclick=function(){a.parentNode.removeChild(a);return false};bbccookies._setPolicy(bbccookies.readPolicy())}var c=g.getElementById("bbccookies");if(c&&!window.orb.fig("uk")){c.className=c.className.replace(/\bbbccookies-d\b/,"");c.className=c.className+(" bbccookies-w")}}})(); /*]]>*/</script> <noscript><p style="position: absolute; top: -999em"><img src="https://web.archive.org/web/20180130201953im_/https://sa.bbc.co.uk/bbc/bbc/s?name=kl.iwonder.guides.knowledge_learning.tomorrows_world.are_we_all_really_martians.zcvtjty.page&ml_name=webmodule&ml_version=89&blq_js_enabled=0&blq_s=4d&blq_r=2.7&blq_v=default&blq_e=pal&page_language=en-GB&page_type=guides&by_nation=eng&clip_count=1&step_max=2&hero_connection=false&first_published_date=2017-08-25T15%3A03%3A44.005964Z&pal_route=guides&app_type=responsive&language=ga-GB&pal_webapp=kandlguides&prod_name=guides&app_name=guides" height="1" width="1" alt=""></p></noscript>  <script type="text/javascript">/*<![CDATA[*/ if (typeof bbccookies !== 'undefined' && bbccookies.isAllowed('s1')) { (function () { require(['istats-1'], function (istats) { istatsTrackingUrl = istats.getDefaultURL(); if (istats.isEnabled() && bbcFlagpoles_istats === 'ON') { sitestat(istatsTrackingUrl); } else { window.ns_pixelUrl = istatsTrackingUrl; /* used by Flash library to track */ } function sitestat(n) { var j = document, f = j.location, b = ""; if (j.cookie.indexOf("st_ux=") != -1) { var k = j.cookie.split(";"); var e = "st_ux", h = document.domain, a = "/"; if (typeof ns_ != "undefined" && typeof ns_.ux != "undefined") { e = ns_.ux.cName || e; h = ns_.ux.cDomain || h; a = ns_.ux.cPath || a } for (var g = 0, f = k.length; g < f; g++) { var m = k[g].indexOf("st_ux="); if (m != -1) { b = "&" + decodeURI(k[g].substring(m + 6)) } } bbccookies.set(e + "=; expires=" + new Date(new Date().getTime() - 60).toGMTString() + "; path=" + a + "; domain=" + h); } window.ns_pixelUrl = n; } }); })(); } else { window.istats = {enabled: false}; } /*]]>*/</script>   <header id="orb-banner" role="banner">   <div id="orb-header" class="orb-nav-pri orb-nav-pri-black b-header--black--white orb-nav-empty"> <div class="orb-nav-pri-container b-r b-g-p"> <div class="orb-nav-section orb-nav-blocks"> <a href="/web/20180130201953/http://www.bbc.co.uk/"> <img class="orb-nav-theme-dynamic" src="https://web.archive.org/web/20180130201953im_/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/img/bbc-blocks-light.png" width="84" height="24" alt="BBC" data-activesrc="https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/img/bbc-blocks-dark.png"/> </a> </div> <section> <div class="orb-skip-links"> <h2>Naisc inrochtaineachta</h2> <ul> <li><a href="#guide">Scipe谩il chuig 谩bhar</a></li> <li><a id="orb-accessibility-help" href="/web/20180130201953/http://www.bbc.co.uk/accessibility/">Cuidi煤 Inrochtaineachta</a></li> </ul> </div> </section> <div id="mybbc-wrapper" class="orb-nav-section orb-nav-id orb-nav-focus"> <div id="idcta-statusbar" class="orb-nav-section orb-nav-focus"> <a id="idcta-link" href="https://web.archive.org/web/20180130201953/https://account.bbc.com/account?lang=ga-GB&ptrt=http%3A%2F%2Fwww.bbc.co.uk%2Fguides%2Fzcvtjty"> <span id="idcta-username">BBC iD</span> </a> </div> <script type="text/javascript"> require(['idcta/statusbar'], function(statusbar) { new statusbar.Statusbar({"id":"idcta-statusbar","locale":"ga-GB","publiclyCacheable":true}); }); </script> <a id="notification-link" class="js-notification-link animated three" href="#"> <span class="hidden-span">Notifications</span> <div class="notification-link--triangle"></div> <div class="notification-link--triangle"></div> <span id="not-num"></span> </a> </div> <nav role="navigation" class="orb-nav"> <div class="orb-nav-section orb-nav-links orb-nav-focus" id="orb-nav-links"> <h2>Nasclean煤int BBC</h2> <ul> <li class="orb-nav-home orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/">Baile</a> </li> <li class="orb-nav-homedotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/">Baile</a> </li> <li class="orb-nav-news orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/news">Nuacht</a> </li> <li class="orb-nav-newsdotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/news">Nuacht</a> </li> <li class="orb-nav-sport"> <a href="/web/20180130201953/http://www.bbc.co.uk/sport/">Sp贸rt</a> </li> <li class="orb-nav-weather"> <a href="/web/20180130201953/http://www.bbc.co.uk/weather/">Aimsir</a> </li> <li class="orb-nav-shop orb-w"> <a href="https://web.archive.org/web/20180130201953/http://shop.bbc.com/">Shop</a> </li> <li class="orb-nav-earthdotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/earth/">Earth</a> </li> <li class="orb-nav-travel-dotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/travel/">Travel</a> </li> <li class="orb-nav-capital orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/capital/">Capital</a> </li> <li class="orb-nav-iplayer orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/iplayer/">iPlayer</a> </li> <li class="orb-nav-culture orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/culture/">Culture</a> </li> <li class="orb-nav-autos orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/autos/">Autos</a> </li> <li class="orb-nav-future orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/future/">Todhcha铆</a> </li> <li class="orb-nav-tv"> <a href="/web/20180130201953/http://www.bbc.co.uk/tv/">Teilif铆s</a> </li> <li class="orb-nav-radio"> <a href="/web/20180130201953/http://www.bbc.co.uk/radio/">Raidi贸</a> </li> <li class="orb-nav-cbbc"> <a href="/web/20180130201953/http://www.bbc.co.uk/cbbc">CBBC</a> </li> <li class="orb-nav-cbeebies"> <a href="/web/20180130201953/http://www.bbc.co.uk/cbeebies">CBeebies</a> </li> <li class="orb-nav-food"> <a href="/web/20180130201953/http://www.bbc.co.uk/food/">Food</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/iwonder">iWonder</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/education">Bitesize</a> </li> <li class="orb-nav-travel orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/travel/">Travel</a> </li> <li class="orb-nav-music"> <a href="/web/20180130201953/http://www.bbc.co.uk/music/">Music</a> </li> <li class="orb-nav-earth orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/earth/">Earth</a> </li> <li class="orb-nav-arts"> <a href="/web/20180130201953/http://www.bbc.co.uk/arts/">Na hEala铆ona</a> </li> <li class="orb-nav-makeitdigital"> <a href="/web/20180130201953/http://www.bbc.co.uk/makeitdigital">Make It Digital</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/taster">Taster</a> </li> <li class="orb-nav-nature orb-w"> <a href="/web/20180130201953/http://www.bbc.co.uk/nature/">Nature</a> </li> <li class="orb-nav-local"> <a href="/web/20180130201953/http://www.bbc.co.uk/local/">Local</a> </li> <li class="orb-nav-tomorrowsworld orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/tomorrowsworld">Tomorrow's World</a> </li> <li id="orb-nav-more"><a href="#orb-footer" data-alt="N铆os聽M贸">Menu<span class="orb-icon orb-icon-arrow"></span></a></li> </ul> </div> </nav> <div class="orb-nav-section orb-nav-search"> <a class="orb-search__button" href="https://web.archive.org/web/20180130201953/https://search.bbc.co.uk/search" title="Aimsigh t茅arma">Aimsigh</a> <form class="b-f" id="orb-search-form" role="search" method="get" action="https://web.archive.org/web/20180130201953/https://search.bbc.co.uk/search" accept-charset="utf-8"> <div> <label for="orb-search-q">Aimsigh t茅arma</label> <input id="orb-search-q" type="text" autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false" name="q" placeholder="Aimsigh"> <button id="orb-search-button" class="orb-search__button">Aimsigh t茅arma</button> <input type="hidden" name="suggid" id="orb-search-suggid"/> </div> </form> </div> </div> <div id="orb-panels"> <script type="text/template" id="orb-panel-template"><![CDATA[ <div id="orb-panel-<%= panelname %>" class="orb-panel" aria-labelledby="orb-nav-<%= panelname %>"> <div class="orb-panel-content b-g-p b-r"> <%= panelcontent %> </div> </div> ]]></script> </div> </div> </header>  <div id="orb-modules"> <div class="k-content" itemscope itemtype="http://schema.org/WebPage"> <div role="main" id="guide" class="k-guide one-step-guide colour-palette-15 brand-tomorrows-world"><div class="k-iwonder-content"><div class="k-g-introduction-media one-step-guide-hero"><div class="one-step-guide-hero__image k-g-int-i" data-image-recipe="http://ichef.bbci.co.uk/images/ic/$recipe/p05d9yy8.jpg"><noscript><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/1600xn/p05d9yy8.jpg" alt=""></noscript></div></div><div class="b-r b-g-p k-g-logo-container"><a class="logo" href="/web/20180130201953/http://www.bbc.co.uk/tomorrowsworld">Tomorrow's World</a></div></div><header class="k-g-header k-g-transparent"><div class="k-g-gtb"><h1>Are we all really Martians?</h1></div></header><section class="k-g-stp-container odd k-g-media non-boxed"><div class="k-g-stp-limiter"><div class="k-g-stp-header"><div class="k-g-stp-header-inner"><span id="zyp797h" class="k-g-stp-anchor" tabindex="-1"></span></div></div><div class="k-g-stp k-g-guide-stp-media"><div class="k-g-stp-inner"><div class="kg-media kg-media--highlight k-g-gs-v video" itemprop="video" itemscope="itemscope" itemtype="http://schema.org/VideoObject"><meta itemprop="name" content="Does life on Earth originate from Mars?"><meta itemprop="description" content="Exploring the science that links the origin of life on our planet to life on Mars."><meta itemprop="thumbnailUrl" content="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/320x180/p05db31g.jpg"><meta itemprop="guidance" content=""><div class="emp" tabindex="0" data-pid="p05db2bn" data-poster-template="http://ichef.bbci.co.uk/images/ic/$recipe/p05db31g.jpg" data-version-pid="p05db2bw" data-guidance=""><noscript><div class="emp-fallback no-javascript"><p>Please turn on JavaScript. Media requires JavaScript to play.</p></div></noscript></div></div><div class="k-g-gs-tb k-type-body-article"><p>Scientists have traced humanity's story on Earth back 3.5 billion years to simple microbial life forms. But where did these come from? Is it possible that they travelled here from Mars?</p></div></div></div></div></section><section class="k-g-stp-container step-number-2 end-step"><div class="k-g-stp k-g-end"><div class="k-g-stp-inner"><span id="z2jcfcw" class="k-g-stp-anchor"></span><h2 class="k-g-gs-t k-type-header"><span class="step-title__step-number">2. </span><span class="step-title__title">Where next?</span></h2><div class="k-promo-panel"><div class=" k-iwonder-promo promo-1 k-colour-palette-palette-1"><a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/guides/z3c9y4j"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x160/p05ccyz9.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p05ccyz9.jpg" alt=""><span class="overlay"></span></div><div class="context"><p class="title">Tomorrow's World Live</p></div></a></div><div class=" k-gel-promo promo-2"><a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/programmes/p05bf1jt"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x90/p05c09vz.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p05c09vz.jpg" alt=""><span class=""></span><span class="overlay"></span></div><div class="context"><p class="title">Astronauts: Do you have what it takes?</p></div><div class="connection"><p><span class="type">From</span><span class="name">BBC Two</span><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/80x80/p05164x4.jpg" alt=""></p></div></a></div><div class=" k-iwonder-promo promo-3 k-colour-palette-palette-5"><a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/guides/zctgq6f"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x160/p01rwf4j.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p01rwf4j.jpg" alt=""><span class="overlay"></span></div><div class="context"><p class="title">What makes space travel so dangerous?</p></div><div class="connection"><p><span class="type">Presented by </span><span class="name">Dara 脫 Briain</span><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/80x80/p01t08hv.jpg" alt=""></p></div></a></div><div class=" k-iwonder-promo promo-4 k-colour-palette-palette-5"><a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/programmes/articles/3V0kR9Hwlr6CPwFY0KTCQ96/tim-peakes-five-facts-about-space-flight"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x160/p05by1lx.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p05by1lx.jpg" alt=""><span class="overlay"></span></div><div class="context"><p class="title">Five fascinating space flight facts</p></div></a></div><div class=" k-iwonder-promo promo-5 k-colour-palette-palette-1"><a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/guides/zws4ycw"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x160/p03rft38.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p03rft38.jpg" alt=""><span class="overlay"></span></div><div class="context"><p class="title">Who owns space?</p></div><div class="connection"><p><span class="type">Presented by</span><span class="name">Dr Marek Kukula</span><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/80x80/p03rft99.jpg" alt=""></p></div></a></div><div class=" k-gel-promo promo-6"><a href="https://web.archive.org/web/20180130201953/http://www.sciencemuseum.org.uk/visitmuseum/plan_your_visit/exhibitions/soyuz-tma-19m-tim-peakes-spacecraft"><div class="media"><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/160x90/p05byp7d.jpg" data-image-recipe="https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/p05byp7d.jpg" alt=""><span class="k-g-sprite icon k-link">Visit</span><span class="overlay"></span></div><div class="context"><p class="title">Tim Peake's spacecraft</p></div><div class="connection"><p><span class="type">From</span><span class="name">Science Museum </span><img src="https://web.archive.org/web/20180130201953im_/http://ichef.bbci.co.uk/images/ic/80x80/p05mkb29.jpg" alt=""></p></div></a></div></div></div></div></section><footer class="k-g-footer"></footer></div> </div> </div> <div id="orb-footer" class="orb-footer orb-footer-grey b-footer--grey--white"> <aside role="complementary"> <div id="orb-aside" class="orb-nav-sec b-r b-g-p"> <div class="orb-footer-inner" role="navigation"> <h2 class="orb-footer-lead">Taisc茅al an BBC</h2> <div class="orb-footer-primary-links"> <ul> <li class="orb-nav-home orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/">Baile</a> </li> <li class="orb-nav-homedotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/">Baile</a> </li> <li class="orb-nav-news orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/news">Nuacht</a> </li> <li class="orb-nav-newsdotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/news">Nuacht</a> </li> <li class="orb-nav-sport"> <a href="/web/20180130201953/http://www.bbc.co.uk/sport/">Sp贸rt</a> </li> <li class="orb-nav-weather"> <a href="/web/20180130201953/http://www.bbc.co.uk/weather/">Aimsir</a> </li> <li class="orb-nav-shop orb-w"> <a href="https://web.archive.org/web/20180130201953/http://shop.bbc.com/">Shop</a> </li> <li class="orb-nav-earthdotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/earth/">Earth</a> </li> <li class="orb-nav-travel-dotcom orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/travel/">Travel</a> </li> <li class="orb-nav-capital orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/capital/">Capital</a> </li> <li class="orb-nav-iplayer orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/iplayer/">iPlayer</a> </li> <li class="orb-nav-culture orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/culture/">Culture</a> </li> <li class="orb-nav-autos orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/autos/">Autos</a> </li> <li class="orb-nav-future orb-w"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/future/">Todhcha铆</a> </li> <li class="orb-nav-tv"> <a href="/web/20180130201953/http://www.bbc.co.uk/tv/">Teilif铆s</a> </li> <li class="orb-nav-radio"> <a href="/web/20180130201953/http://www.bbc.co.uk/radio/">Raidi贸</a> </li> <li class="orb-nav-cbbc"> <a href="/web/20180130201953/http://www.bbc.co.uk/cbbc">CBBC</a> </li> <li class="orb-nav-cbeebies"> <a href="/web/20180130201953/http://www.bbc.co.uk/cbeebies">CBeebies</a> </li> <li class="orb-nav-food"> <a href="/web/20180130201953/http://www.bbc.co.uk/food/">Food</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/iwonder">iWonder</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/education">Bitesize</a> </li> <li class="orb-nav-travel orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/travel/">Travel</a> </li> <li class="orb-nav-music"> <a href="/web/20180130201953/http://www.bbc.co.uk/music/">Music</a> </li> <li class="orb-nav-earth orb-d"> <a href="https://web.archive.org/web/20180130201953/http://www.bbc.com/earth/">Earth</a> </li> <li class="orb-nav-arts"> <a href="/web/20180130201953/http://www.bbc.co.uk/arts/">Na hEala铆ona</a> </li> <li class="orb-nav-makeitdigital"> <a href="/web/20180130201953/http://www.bbc.co.uk/makeitdigital">Make It Digital</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/taster">Taster</a> </li> <li class="orb-nav-nature orb-w"> <a href="/web/20180130201953/http://www.bbc.co.uk/nature/">Nature</a> </li> <li class="orb-nav-local"> <a href="/web/20180130201953/http://www.bbc.co.uk/local/">Local</a> </li> <li class="orb-nav-tomorrowsworld orb-d"> <a href="/web/20180130201953/http://www.bbc.co.uk/tomorrowsworld">Tomorrow's World</a> </li> </ul> </div> </div> </div> </aside> <footer role="contentinfo"> <div id="orb-contentinfo" class="orb-nav-sec b-r b-g-p"> <div class="orb-footer-inner"> <ul> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/terms/">T茅arma铆煤s谩ide</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/aboutthebbc/">Faoin BBC</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/privacy/">Pr铆obh谩ideacht</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/privacy/cookies/about">Fian谩in</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/accessibility/">Cuidi煤 Inrochtaineachta</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/guidance/">Treoir do thuismitheoir铆</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/contact/">D茅an teagmh谩il linn</a> </li> <li> <a href="/web/20180130201953/http://www.bbc.co.uk/bbcnewsletter">Get Personalised Newsletters</a> </li> <li class=" orb-w"> <a href="https://web.archive.org/web/20180130201953/http://advertising.bbcworldwide.com/">D茅an F贸gra铆ocht Linne</a> </li> <li class=" orb-w"> <a href="/web/20180130201953/http://www.bbc.co.uk/privacy/cookies/international/">Roghanna F贸gra铆ochta</a> </li> </ul> <small> <span class="orb-hilight">Copyright © 2018 BBC.</span> The BBC is not responsible for the content of external sites. <a href="/web/20180130201953/http://www.bbc.co.uk/help/web/links/" class="orb-hilight">Read about our approach to external linking.</a> </small> </div> </div> </footer> </div> <div class="bbccom_display_none"><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && window.bbcdotcom.analytics && bbcdotcom.config && !bbcdotcom.config.isSportApp()) { bbcdotcom.analytics.page(); } /*]]>*/ </script><noscript><img src="//web.archive.org/web/20180130201953im_/http://ssc.api.bbc.com/?c1=2&c2=19293874&ns_site=bbc&name=" height="1" width="1" alt=""></noscript><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && bbcdotcom.currencyProviders) { bbcdotcom.currencyProviders.write(); } /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && bbcdotcom.currencyProviders) { bbcdotcom.currencyProviders.postWrite(); } /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && bbcdotcom.data && bbcdotcom.data.stats && bbcdotcom.data.stats == 1 && bbcdotcom.config && bbcdotcom.config.isLotameEnabled && bbcdotcom.config.isLotameEnabled() && bbcdotcom.lotame){ bbcdotcom.lotame.write(); } /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && bbcdotcom.data && bbcdotcom.data.stats && bbcdotcom.data.stats === 1 && bbcdotcom.utils && window.location.pathname === '/' && window.bbccookies && bbccookies.readPolicy('performance') ) { var wwhpEdition = bbcdotcom.utils.getMetaPropertyContent('wwhp-edition'); var _sf_async_config={}; /** CONFIGURATION START **/ _sf_async_config.uid = 50924; _sf_async_config.domain = "bbc.co.uk"; _sf_async_config.title = "Homepage"+(wwhpEdition !== '' ? ' - '+wwhpEdition : ''); _sf_async_config.sections = "Homepage"+(wwhpEdition !== '' ? ', Homepage - '+wwhpEdition : ''); _sf_async_config.region = wwhpEdition; _sf_async_config.path = "/"+(wwhpEdition !== '' ? '?'+wwhpEdition : ''); /** CONFIGURATION END **/ (function(){ function loadChartbeat() { window._sf_endpt=(new Date()).getTime(); var e = document.createElement("script"); e.setAttribute("language", "javascript"); e.setAttribute("type", "text/javascript"); e.setAttribute('src', '//web.archive.org/web/20180130201953/http://static.chartbeat.com/js/chartbeat.js'); document.body.appendChild(e); } var oldonload = window.onload; window.onload = (typeof window.onload != "function") ? loadChartbeat : function() { oldonload(); loadChartbeat(); }; })(); } /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ if (window.bbcdotcom && bbcdotcom.data && bbcdotcom.data.stats == 1 ) { var js_loaded=false, percent; if (window.bbcdotcom && bbcdotcom.config && bbcdotcom.config.isSherlockEnabled()) { document.write('<script src="//web.archive.org/web/20180130201953/http://stag.mdotlabs.com/ads.js">\x3C/script>'); if(document.location.protocol === "http:"){ document.write('<script src="//web.archive.org/web/20180130201953/http://stag.mdotlabs.com/sherlock.php?clientID=19293874">\x3C/script>'); } else { document.write('<script src="//web.archive.org/web/20180130201953/http://stag.mdotlabs.com/sherlock.php?clientID=19293874&sec=1">\x3C/script>'); } } } /*]]>*/ </script><script type="text/javascript"> /*<![CDATA[*/ (function() { window.bbcdotcom.bodyLast = true; }()); /*]]>*/ </script></div> <script type="text/javascript" id="orb-js-script" data-assetpath="http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/" src="https://web.archive.org/web/20180130201953js_/http://static.bbci.co.uk/frameworks/barlesque/3.21.31/orb/4/script/orb.min.js"></script> <script type="text/javascript"> require.config({ paths: { "mybbc/templates": '//web.archive.org/web/20180130201953/http://mybbc.files.bbci.co.uk/notification-ui/3.8.4/templates', "mybbc/notifications": '//web.archive.org/web/20180130201953/http://mybbc.files.bbci.co.uk/notification-ui/3.8.4/js' } }); require(['mybbc/notifications/NotificationsMain', 'idcta/idcta-1'], function (NotificationsMain, idcta) { var loadNotifications = function (fig) { if (fig.geo.isUK()) { NotificationsMain.run(idcta, '//web.archive.org/web/20180130201953/http://mybbc.files.bbci.co.uk/notification-ui/3.8.4/'); } }; var orbFig = window.orb.fig; if (typeof orbFig.load === 'function') { // Use new async API from Orbit orbFig.load(loadNotifications, loadNotifications); } else { // Use old sync-only API from PAL orbfig project loadNotifications(orbFig); } }); </script> <script type="text/javascript"> if (typeof require !== 'undefined') { require(['istats-1'], function(istats){ istats.track('external', { region: document.getElementsByTagName('body')[0] }); istats.track('download', { region: document.getElementsByTagName('body')[0] }); }); } </script> <script type="text/javascript"> if (window.SEARCHBOX.suppress === false && window.SEARCHBOX.locale && /^en-?.*?/.test(window.SEARCHBOX.locale)) { require.config({ paths: { "search/searchbox": window.SEARCHBOX.searchboxAppStaticPrefix, "disco-layer": "//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/discovery-layer/0.0.1-117.f862de7/app" } }); require(['search/searchbox/searchboxDrawer'], function (SearchboxDrawer) { SearchboxDrawer.run(window.SEARCHBOX); }); var loadDiscoveryLayer = function (fig) { if (fig.geo.isUK()) { require(['disco-layer'], function (discoLayer) { discoLayer.run("//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/discovery-layer/content/", "//web.archive.org/web/20180130201953/http://nav.files.bbci.co.uk/discovery-layer/0.0.1-117.f862de7/main.css"); }); } }; var orbFig = window.orb.fig; if (typeof orbFig.load === 'function') { // Use new async API from Orbit orbFig.load(loadDiscoveryLayer); } else { // Use old sync-only API from PAL orbfig project loadDiscoveryLayer(orbFig); } } </script> <script> /*! modernizr 3.3.1 (Custom Build) | MIT * * https://modernizr.com/download/?-svg-touchevents-setclasses-cssclassprefix:k- !*/ !function(e,n,t){function o(e,n){return typeof e===n}function s(){var e,n,t,s,a,i,r;for(var l in c)if(c.hasOwnProperty(l)){if(e=[],n=c[l],n.name&&(e.push(n.name.toLowerCase()),n.options&&n.options.aliases&&n.options.aliases.length))for(t=0;t<n.options.aliases.length;t++)e.push(n.options.aliases[t].toLowerCase());for(s=o(n.fn,"function")?n.fn():n.fn,a=0;a<e.length;a++)i=e[a],r=i.split("."),1===r.length?Modernizr[r[0]]=s:(!Modernizr[r[0]]||Modernizr[r[0]]instanceof Boolean||(Modernizr[r[0]]=new Boolean(Modernizr[r[0]])),Modernizr[r[0]][r[1]]=s),f.push((s?"":"no-")+r.join("-"))}}function a(e){var n=u.className,t=Modernizr._config.classPrefix||"";if(p&&(n=n.baseVal),Modernizr._config.enableJSClass){var o=new RegExp("(^|\\s)"+t+"no-js(\\s|$)");n=n.replace(o,"$1"+t+"js$2")}Modernizr._config.enableClasses&&(n+=" "+t+e.join(" "+t),p?u.className.baseVal=n:u.className=n)}function i(){return"function"!=typeof n.createElement?n.createElement(arguments[0]):p?n.createElementNS.call(n,"http://www.w3.org/2000/svg",arguments[0]):n.createElement.apply(n,arguments)}function r(){var e=n.body;return e||(e=i(p?"svg":"body"),e.fake=!0),e}function l(e,t,o,s){var a,l,f,c,d="modernizr",p=i("div"),h=r();if(parseInt(o,10))for(;o--;)f=i("div"),f.id=s?s[o]:d+(o+1),p.appendChild(f);return a=i("style"),a.type="text/css",a.id="s"+d,(h.fake?h:p).appendChild(a),h.appendChild(p),a.styleSheet?a.styleSheet.cssText=e:a.appendChild(n.createTextNode(e)),p.id=d,h.fake&&(h.style.background="",h.style.overflow="hidden",c=u.style.overflow,u.style.overflow="hidden",u.appendChild(h)),l=t(p,e),h.fake?(h.parentNode.removeChild(h),u.style.overflow=c,u.offsetHeight):p.parentNode.removeChild(p),!!l}var f=[],c=[],d={_version:"3.3.1",_config:{classPrefix:"k-",enableClasses:!0,enableJSClass:!0,usePrefixes:!0},_q:[],on:function(e,n){var t=this;setTimeout(function(){n(t[e])},0)},addTest:function(e,n,t){c.push({name:e,fn:n,options:t})},addAsyncTest:function(e){c.push({name:null,fn:e})}},Modernizr=function(){};Modernizr.prototype=d,Modernizr=new Modernizr,Modernizr.addTest("svg",!!n.createElementNS&&!!n.createElementNS("http://www.w3.org/2000/svg","svg").createSVGRect);var u=n.documentElement,p="svg"===u.nodeName.toLowerCase(),h=d._config.usePrefixes?" -webkit- -moz- -o- -ms- ".split(" "):["",""];d._prefixes=h;var m=d.testStyles=l;Modernizr.addTest("touchevents",function(){var t;if("ontouchstart"in e||e.DocumentTouch&&n instanceof DocumentTouch)t=!0;else{var o=["@media (",h.join("touch-enabled),("),"heartz",")","{#modernizr{top:9px;position:absolute}}"].join("");m(o,function(e){t=9===e.offsetTop})}return t}),s(),a(f),delete d.addTest,delete d.addAsyncTest;for(var v=0;v<Modernizr._q.length;v++)Modernizr._q[v]();e.Modernizr=Modernizr}(window,document); var bumpUrl = 'https://web.archive.org/web/20180130201953/https://emp.bbci.co.uk/emp/bump-3/bump-3'; require.config({ paths: { 'bump-3': bumpUrl, 'echo': 'https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/echo', 'embed': 'https://web.archive.org/web/20180130201953/http://static.bbci.co.uk/kandlguides/4.22.32.7202/modules/kandlguides-vendors/playpen' } }); require(["kandlguides/controller/page"], function(Page) { var page = new Page({ controllers: [ "kandlguides/controller/activity", "kandlguides/controller/adverts", "kandlguides/controller/introduction", "kandlguides/controller/media", "kandlguides/controller/navigation", "kandlguides/controller/bitesize", "kandlguides/controller/relatedContentPanel", "kandlguides/controller/responsiveImages", "kandlguides/controller/singleQuestion", "kandlguides/controller/slideshow", "kandlguides/controller/stepLink", "kandlguides/controller/title", "kandlguides/controller/userMonitoring", "kandlguides/controller/vote", "kandlguides/controller/openGamesActivity" ], config: { media: { mediaTemplateUrl: "https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/clip/$pid.jpg", mediaBaseUrl: "https://web.archive.org/web/20180130201953/http://www.bbc.co.uk/iplayer/playlist/", daxComscore: { appName: 'guides', appType: 'responsive', counterName: 'kl.iwonder.guides.knowledge_learning.tomorrows_world.are_we_all_really_martians.zcvtjty.page' }, embed: true }, image: { recipe: "https://web.archive.org/web/20180130201953/http://ichef.bbci.co.uk/images/ic/$recipe/$pid.jpg" }, infographic: { recipe: "https://web.archive.org/web/20180130201953/https://bam.files.bbci.co.uk/bam/live/content/$pid/$recipe" }, language: "ga", suppressActivities: "false" } }); page.init(); }); if (bbccookies.cookiesEnabled() && bbccookies.readPolicy('performance')) { var _sf_async_config = {}; /** CONFIGURATION START **/ _sf_async_config.uid = 50924; _sf_async_config.domain = "bbc.co.uk"; _sf_async_config.useCanonical = true; _sf_async_config.sections = ""; _sf_async_config.authors = ""; /** CONFIGURATION END **/ (function(){ function loadChartbeat() { window._sf_endpt=(new Date()).getTime(); var e = document.createElement("script"); e.setAttribute("language", "javascript"); e.setAttribute("type", "text/javascript"); e.setAttribute('src', '//web.archive.org/web/20180130201953/http://static.chartbeat.com/js/chartbeat.js'); document.body.appendChild(e); } var oldonload = window.onload; window.onload = (typeof window.onload != "function") ? loadChartbeat : function() { oldonload(); loadChartbeat(); }; })(); } </script> <script type="text/javascript">require(["megavolt-client","istats-1","orb/cookies"],function(t,e,i){function o(){return"true"===l&&a&&t&&"function"==typeof t.getMVTIStatsLabels}function n(){!c&&o()?setTimeout(function(){e.invoke()},"500"):e.invoke()}var s=navigator.userAgent.toLowerCase(),a=!(s.indexOf("msie")>-1)||parseInt(s.split("msie")[1],10)>10,c=!1,l="true";if(i.isAllowed("s1"))try{if(o()&&t.getMVTIStatsLabels(function(t){e.addLabels(t),c=!0}),!require.s.contexts._.config.paths.idcta)return void n();require(["idcta/idcta-1"],function(t){t&&"function"==typeof t.getIStatsLabels&&e.addLabels(t.getIStatsLabels()),n()},function(t){throw t})}catch(t){console&&"function"==typeof console.log&&console.log("an exception occurred while adding idcta labels to istats, invoking istats without them",t),n()}});</script> </body> </html>