{"group":"life","pic":"living/pics/moving-city.webp","question":"What does it feel like to walk on Mars?","answer":"Light. You weigh {g_pct}% of what you do on Earth, so every step carries you further and every jump floats. People here move in long, easy bounds.","play":{"label":"Bound across the plain","href":"play/?era=city&light=day"},"earth_mars":{"earth":{"head":"Gravity holds you close"},"mars":{"head":"Gravity lets you fly"},"pics":{"earth":"living/pics/em-moving-earth.webp","mars":"living/pics/em-moving-mars.webp"},"rows":[{"label":"Your weight","icon":"walk","earth":"You feel every kilogram you carry.","mars":"You feel {g_pct}% of your weight: a {suit_kg} kg spacesuit feels like {suit_feel} kg."},{"label":"A jump","icon":"spark","earth":"An easy hop barely clears a step.","mars":"The same push lifts you {jump_x} times as high, and you hang in the air {jump_x} times as long."}]},"pin":[0.84,0.66],"close":{"title":"How heavy you feel","line":"Pick a world and watch the same push lift you.","worlds":[{"id":"earth","name":"Earth"},{"id":"mars","name":"Mars"},{"id":"moon","name":"The Moon"}],"weight":"You weigh","weight_unit":"% of your Earth weight","suit":"Your {suit_kg} kg suit feels like","hop":"The same hop rises","air":"and hangs in the air","times":"times as high","times_air":"times as long"},"tiles_title":"A city built for bounding","tiles":[{"icon":"stair","title":"Built to bound","text":"Ceilings stand high and stairs climb steep, because people here take them in a few long, easy bounds."},{"icon":"track","title":"Strong every day","text":"Everyone trains every day, and sport counts: a run round the park track, a game on the court, a climb in the gym."},{"icon":"pair","title":"Out in pairs","text":"On the plain, suited friends bound side by side along graded paths, leaving long lines of boot prints in the red dust."}],"arcs":{"title":"Same push, higher hop","line":"Both arcs are drawn to the same scale: one push from the same legs, on each world.","earth":"On Earth","mars":"On Mars","note":"Mars pulls with {g_pct}% of Earth's gravity, so the jump rises {jump_x} times as high and lasts {jump_x} times as long."},"gait":{"title":"When a walk becomes a run","line":"In harness tests that took away part of each person's weight, people broke into a run sooner and sooner as gravity fell.","x":"Gravity, share of Earth's","y":"Speed where walking turns to running, m/s","earth":"Earth","mars":"Mars","note":"At {kr_g} g, the setting nearest Mars, people broke into a run at {kr_04} m/s: an easy Earth stroll of {kr_04_kmh} km/h. So on Mars a stroll is already a lope."},"scene":{"pic":"living/pics/scene-moving.webp","look":"02-06","shot":"track","focus":"50% 50%","spots":[{"at":[0.885,0.53]},{"at":[0.19,0.66]},{"at":[0.385,0.53]}]},"proof":{"pic":"living/people/moving-proof.webp","place":"Sea of Tranquillity, the Moon","when":"{bp_date}","head":"A footprint that was a science test","credit":"Photo: Buzz Aldrin, NASA (public domain)"},"fact":"On {bp_date}, about an hour into the first moonwalk, Buzz Aldrin pressed his boot into fresh dust and photographed the print. It was a soil test: how the ground packs under a step. It became the most famous footprint in history.","quiz":[{"q":"How much higher does the same push lift you on Mars?","a":["About {jump_x} times as high","About the same as on Earth","Ten times as high"],"why":"Mars pulls with {g_pct}% of Earth's gravity, so the same push lifts you {jump_x} times as high and keeps you in the air {jump_x} times as long.","more":"The longest anyone has lived on another world is Apollo 17's {a17_h} hours on the Moon, in December 1972.","cite":"02-01 S-02, 02-06 F-15","from":"why","fig":0,"icon":"walk"},{"q":"At what pace does a walk turn into a run near Mars gravity?","a":["About {kr_04} m/s, an easy Earth stroll","About {kr_1} m/s, the same as on Earth","Only at a full sprint"],"why":"In harness tests at {kr_g} g, people broke into a run at {kr_04} m/s, against {kr_1} m/s in full gravity.","more":"Dust you kick up flies about {throw_x} times as far as on Earth, in long, slow arcs.","cite":"02-06 F-17, 02-01 S-12","from":"why","fig":1,"icon":"bar"},{"q":"How heavy does a {suit_kg} kg spacesuit feel on Mars?","a":["Like {suit_feel} kg on Earth","Just as heavy as on Earth","It weighs nothing"],"why":"Everything here weighs {g_pct}% of what it does on Earth, spacesuits included.","more":"Mars pulls almost the same everywhere: {g_eq} m/s² at the equator and {g_pole} m/s² at the poles.","cite":"03-08 SS-04, 02-01 F-01","from":"problem","fig":0,"icon":"helmet"}],"notes":[{"beat":"fix","text":"The Apollo crews found a bounding lope the easiest way to cross the Moon. Settlers here move the same way, just a little heavier and quicker.","cite":"02-01 S-01"}],"everyday":{"title":"A day on your feet","items":[{"time":"07:10","head":"A morning run","text":"A loop of the park track under the water roof before breakfast. Every stride sails a long way and lands softly.","tag":"{g_pct}% of Earth's pull","pic":"living/pics/scene-moving.webp","pos":"18% 66%"},{"time":"12:30","head":"Up to the roof in three bounds","text":"The stair to the terrace is steep, and you take it the way everyone does: a few long, easy hops.","tag":"{jump_x}× the hop","pic":"living/pics/scene-moving.webp","pos":"88% 50%"},{"time":"18:20","head":"Games in the park","text":"Children leap for a frisbee and land laughing. A brisk walk home turns into a lope without you trying.","tag":"Lope at {kr_04_kmh} km/h","pic":"living/pics/moving-far.webp","pos":"55% 60%"}]},"living":"I bounce everywhere now. The stairs to our roof take three easy steps, the children leap like dancers in the park, and a walk to the café feels like floating. Out on the plain we lope along in pairs, leaving long lines of boot prints in the red dust.","from":"From the park track","later":{"pics":{"city":"living/pics/moving-city.webp","far":"living/pics/moving-far.webp"},"city":{"tag":"Bounding in pairs","text":"Suited crews lope between the buried rows in long, low bounds, and runners circle the first dome's park track."},"far":{"tag":"Leaps in the park","text":"Families and children leap across the grass under the water roofs: bounding is simply how everyone moves."}}}