What If You Tried to Stand on Miranda?

What if you tried to stand on Miranda, the small, patchwork moon of Uranus that may have the tallest cliff in the solar system? Same person, same teal sweater, same coffee (sealed mug, non-negotiable). Miranda is only about 470 km across, about a seventh the width of our Moon, with roughly the surface area of Texas. It's mostly water ice. Surface gravity is about 0.008 g (0.079 m/s²), so a 70 kg person feels like about half a kilogram: one loaf of sliced bread. Walk faster than about 0.7 km/h and every step becomes a small launch. A half-meter hop at home sends you about 60 m up (a 20-story building), with roughly 80 seconds of airtime. Escape speed is still about 190 m/s, so you can't jump off. The sunlit surface is around −187 °C, and there's no atmosphere at all. That means no wind, no weather and no sound. Miranda is tidally locked, so Uranus hangs fixed in its sky, about 22° across (more than 40 full Moons, about one outstretched hand). Uranus is tipped about 98°, and one orbit takes 84 years. Each pole gets about 42 years of daylight and then about 42 years of night, and Miranda shares those seasons. Verona Rupes may be 5 to 20 km tall. At 20 km, a fall would last about 12 minutes and end at roughly 200 km/h. NASA's Astronomy Picture of the Day suggested it might be survivable with proper airbags. Miranda looks pieced together. Three huge coronae (Arden, Elsinore and Inverness, with its bright "chevron") are each more than 200 km across, and every feature name comes from Shakespeare. Scientists still debate how it happened. One idea is shattering and reassembly. The other, favored by many, is tidal heating from an ancient orbital resonance driving warm ice upward. A 2024 study suggests Miranda may have had an ocean at least 100 km deep under no more than 30 km of ice within the last few hundred million years. It is possible, not proven. Voyager 2 is the only visitor so far (January 24, 1986). It saw only the sunlit southern half. The 2022 decadal survey made a Uranus Orbiter and Probe NASA's top flagship priority, but it has not been approved or built, and NASA's latest budget request gives it no money. Meanwhile, the seasons have turned: the half nobody has ever seen is in sunlight right now. 0:00 Standing on Miranda? 0:03 The moon built from spare parts 0:27 One visitor ever: Voyager 2 0:52 Mismatched ground 1:15 Texas-sized moon 1:35 You weigh one loaf of bread 2:00 An 80-second jump 2:21 −187 °C, but not dark 2:45 No air, no sound 2:56 Uranus fills your hand 3:23 The planet lying on its side 3:53 Verona Rupes: the tallest cliff? 4:19 A 12-minute fall 4:53 Frankenstein's moon 5:25 What happened to Miranda? 5:57 A hidden ocean? Maybe 6:20 Discovered from Texas 6:48 Myth check 7:14 The half nobody has seen 7:46 Back home 8:01 The science, honestly 8:28 Nobody is looking Science sources: NASA Science Miranda overview (science.nasa.gov/uranus/moons/miranda/), NASA NSSDC Uranian satellite fact sheet, Voyager 2 Uranus encounter results (1986), NASA Astronomy Picture of the Day for 2020 November 29 ("Verona Rupes: Tallest Known Cliff in the Solar System"), Strom et al. 2024 (The Planetary Science Journal, Miranda ocean), Hammond & Barr 2014 (Geology, convection origin of coronae), Ćuk, Dones & Nesvorný 2020 (Uranian satellite resonances), Origins, Worlds, and Life: the 2022 planetary science decadal survey, AAS policy reports on NASA FY2026/FY2027 budgets. #Miranda #Uranus #Space #WhatIf #Astronomy #Science #Voyager2 #PlanetaryScience