{"group":"shelter","pic":"living/pics/homes-city.webp","question":"How do you live in the daylight on Mars?","answer":"In daylight. A roof full of water turns the sunlight soft and stops the radiation, and the buried streets do the same under three metres of soil, with skylights pouring the day down.","play":{"label":"Walk into your home","href":"play/?at=14,-132,-1.17,0.18,12&era=city&light=day"},"play_also":[{"label":"Walk the buried street","href":"play/?era=city#row"}],"dose":{"title":"Radiation where you stand","line":"Every streak is radiation arriving from space. Pick a place and watch how much gets through.","places":[{"id":"plain","name":"Out on the plain","shield":"Nothing overhead","big":"{h_plain_y}","unit":"mSv a year","text":"Like {h_plain_xray} chest X-rays every day. People only go out for shifts.","pass":1},{"id":"farm","name":"In a glass farm dome","shield":"Glass only","big":"{h_plain_y}","unit":"mSv a year","text":"Glass lets the radiation straight through, so farm workers count it like time outside.","pass":1},{"id":"dome","name":"Under a water roof","shield":"Water between two skins of glass","big":"Most","unit":"stopped by the water","text":"Water is one of the best shields there is. Under it, people live in everyday clothes.","pass":0.15},{"id":"rows","name":"In the buried rows","shield":"{cover} m of soil","big":"{buried}","unit":"mSv a year at most","text":"About {h_rows_x} times less than the plain: the yearly limit for a radiation worker in the UK.","pass":0.085},{"id":"earth","name":"Back home on Earth","shield":"Thick air and a magnetic field","big":"{earth_bg}","unit":"mSv a year","text":"The natural background everyone on Earth lives with.","pass":0.013}]},"depth_title":"Why three metres of soil?","depth":[{"d":"0 m","title":"On the surface","text":"The full dose."},{"d":"{peak_cm} cm","title":"Worse at first","text":"A thin layer makes it worse: the rays smash into the soil and break into showers of smaller particles."},{"d":"{sh_lo} to {sh_hi} m","title":"Getting safe","text":"Enough soil to bring the dose under {sh_target} mSv a year."},{"d":"{cover} m","title":"Where people sleep","text":"At most {buried} mSv a year, with room to spare."}],"push":{"title":"A blanket, not a lid","line":"The air inside pushes up on every square metre of roof as hard as {h_air_t} tonnes would press down on Mars. {cover} metres of soil weighs only {h_soil_t} tonnes. The air would lift it {h_push_x} times over.","up":"Air pushing up","down":"Soil pressing down","fix":"So every home is a sealed steel shell that holds its own air, and the soil on top only keeps out radiation, cold and stones."},"types_title":"Two ways to live","types":[{"id":"rows","name":"The buried rows","text":"Steel vaults {vault_d} m across and {vault_l} m long, welded from rings like a Starship's. Skylights bring daylight down, and every row has a way out at each end."},{"id":"dome","name":"The neighbourhoods under glass","text":"A great glass dome holds the air and its water roof stops the radiation, so the homes inside are printed from Mars soil, with roof terraces where it never rains."}],"earth_mars":{"earth":{"head":"The sky is a shield"},"mars":{"head":"The sky lets it all through"},"pics":{"earth":"living/pics/em-homes-earth.webp","mars":"living/pics/em-homes-mars.webp"},"rows":[{"label":"Radiation protection","icon":"shield","earth":"Thick air and a magnetic field stop most radiation from space.","mars":"No magnetic field around the planet, and air too thin to stop much."},{"label":"Yearly dose","icon":"rad","earth":"About {earth_bg} mSv from natural background radiation.","mars":"About {h_plain_y} mSv on the open plain: like {h_plain_xray} chest X-rays a day."}]},"living":"Home is warm, quiet and bright. Skylights pour real daylight into the rows, screens show the plain outside, and a viewing room up top looks out over Arcadia at sunset. When a solar storm passes overhead, life inside carries on as usual.","fact":"In May 2024 a solar storm reached Mars. An astronaut standing beside NASA's Curiosity rover would have taken in about {storm_xrays} chest X-rays' worth of radiation.","later":{"pics":{"city":"living/pics/homes-city.webp","far":"living/pics/homes-far.webp"},"city":{"tag":"Buried rows","text":"Most people live in long steel vaults under three metres of soil, and the first neighbourhood under glass rises beside them."},"far":{"tag":"Half under glass","text":"About half the city lives in neighbourhoods under water-roofed domes, with parks and a lake. The rest live in the buried rows, warm and quiet under the soil."}},"pin":[0.86,0.26],"scene":{"pic":"living/pics/scene-homes.webp","look":"03-06","shot":"cut_row","focus":"15% 50%","zoom":1.8,"spots":[{"at":[0.18,0.6]},{"at":[0.38,0.2]}],"lap":90},"depth_marks":{"rays":"Space radiation","you":"You"},"proof":{"pic":"games/mars-or-earth/photos/gale-vista.webp","place":"Gale crater, Mars","when":"May 2024","head":"The day the Sun flared","credit":"Photo: NASA/JPL-Caltech/MSSS, taken by the Curiosity rover in Gale crater"},"quiz":[{"q":"What holds the air in a buried home?","a":["A sealed steel shell","The weight of the soil on top","The Martian air pressing in"],"why":"The air inside pushes up as hard as {h_air_t} tonnes on every square metre. {cover} m of soil weighs only {h_soil_t}, so the steel shell holds the air and the soil just shields.","more":"Britain's Halley VI research station in Antarctica stands on giant skis and legs. In {wq_hal_year} it was simply towed {wq_hal_km} km across the ice to a new spot.","cite":"03-06 HA-02, F-31","from":"why","fig":1,"icon":"house"},{"q":"Why is a thin layer of soil worse than none?","a":["The rays break into showers of smaller particles","It soaks up heat and warms the rays","It stops the radiation alarms from working"],"why":"The rays smash into the soil and break into showers of smaller particles. It takes {sh_lo} to {sh_hi} m of soil to come out ahead.","more":"The South Pole station's winter crew of {wq_pole_lo} to {wq_pole_hi} runs a whole research base on its own from February to October, with the polar night overhead.","cite":"03-06 F-01, F-30","from":"why","fig":0,"icon":"layers"},{"q":"Where can people live in everyday clothes with no soil overhead?","a":["Under a water roof","In a glass farm dome","Out on the plain at night"],"why":"Water is one of the best shields there is. Glass alone lets the radiation straight through.","more":"Some families in Ramsar, Iran, live with natural radiation of up to {wq_ramsar} mSv a year from the ground, and have done for generations. That is more than a settler gets in the buried rows.","cite":"03-10 GF-17, 02-06 F-37","from":"fix","fig":0,"icon":"house"}],"notes":[{"beat":"fix","text":"Starship's steel rings, the kind each home vault is welded from, are just {wq_ring_t} mm thick.","cite":"03-06 F-05"}],"from":"From the buried rows","everyday":{"title":"A day at home","items":[{"time":"08:12","head":"A home of your own","text":"Your own rooms, with a door that's yours: about {h_priv_x} times the cabin an astronaut sleeps in on the space station.","tag":"{h_priv} m³ each","pic":"living/pics/scene-homes.webp","pos":"18% 62%"},{"time":"12:40","head":"Daylight underground","text":"Skylights pour real Martian daylight down into the rows, under a curved steel roof {h_tall} m high at its peak.","tag":"{h_tall} m roof","pic":"living/pics/homes-far.webp","pos":"50% 40%"},{"time":"19:05","head":"Storms pass you by","text":"A solar storm sweeps over the city. Under {cover} metres of soil, nobody even looks up from dinner.","tag":"{cover} m of soil","pic":"living/pics/homes-city.webp","pos":"50% 70%"}]}}