Mars Is Tearing Its Moon Apart (Japan Just Sent a Ship to Grab a Piece)

bigger of Mars's two moons, filmed from the ground by NASA's Perseverance rover. Phobos is falling: it gets about six feet closer to Mars every hundred years. In October 2026, Japan launched MMX to land there and bring a piece of it back to Earth. In this video: why Phobos falls while our own Moon drifts away (the same tides, on opposite sides of a "same-speed" line); why it rises in the west twice a day; the long grooves that may be stretch marks; why it should crumble into a ring instead of crashing; the open question of where it came from; and how MMX, its bouncing rover Idefix and about ten grams of soil should finally answer it in 2031. The 3D Mars system, the breakup and the ring are our own animations of what the models predict; the moons are drawn larger than true scale so you can see them. They are not photographs. Chapters 0:00 A shadow on the Sun 0:43 A moon in a hurry 2:06 Why Phobos is falling 3:41 Stretch marks 4:53 A ring for Mars 6:10 Grabbing a piece: MMX 7:53 A moon is company Sources NASA Science, "Phobos" (size, orbit, rate of fall, Stickney crater): https://science.nasa.gov/mars/moons/p... NASA Goddard (2015), "Mars' Moon Phobos is Slowly Falling Apart" (T. Hurford et al.): https://www.nasa.gov/solar-system/mar... Black & Mittal 2015, "The demise of Phobos and development of a Martian ring system", Nature Geoscience 8, 913 (doi:10.1038/ngeo2583) Bills et al. 2005, "Improved estimate of tidal dissipation within Mars from MOLA observations of the shadow of Phobos", JGR 110, E07004 Hesselbrock & Minton 2017, "An ongoing satellite–ring cycle of Mars and the origins of Phobos and Deimos", Nature Geoscience 10, 266 NASA (2022), "NASA's Perseverance Rover Captures Video of Solar Eclipse on Mars": https://www.nasa.gov/solar-system/nas... NASA NSSDC, Mars fact sheet (orbits of Phobos and Deimos): https://nssdc.gsfc.nasa.gov/planetary... DLR (2026), "Off to the moons of Mars: MMX mission and Idefix rover ready for launch" AP (Oct. 19, 2026), "Japan launches spacecraft to mysterious moons of Mars in a bold mission to bring home soil samples" Linda Hall Library, "Scientist of the Day: Asaph Hall": https://www.lindahall.org/about/news/... Murray & Dermott 1999, Solar System Dynamics (tides) Images and footage (public domain) Phobos eclipsing the Sun, filmed by Perseverance (2022): NASA/JPL-Caltech/ASU/MSSS/SSI Phobos transit, Perseverance (2024): NASA/JPL-Caltech/ASU/MSSS Annular eclipse by Phobos, Curiosity (2013): NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ. Phobos in colour, HiRISE (2008): NASA/JPL-Caltech/University of Arizona Deimos, HiRISE (2009): NASA/JPL-Caltech/University of Arizona Phobos seen by Viking 1 Orbiter (frame 357A64): NASA/JPL (NASA NSSDC) Mars, Viking global colour view: NASA/JPL/USGS Sunset on Mars, Spirit rover (2005): NASA/JPL/Texas A&M/Cornell Earth setting, Phobos rising, Curiosity (2024): NASA/JPL-Caltech/MSSS Mars globe texture: NASA Ames / USGS Astrogeology Science Center (Viking Orbiter data) Phobos globe texture: NASA/JPL/Solar System Simulator Asaph Hall, 1899: U.S. Naval Observatory Library The 26-inch refractor at the U.S. Naval Observatory: U.S. Navy photo by Chief Warrant Officer 4 Seth Rossman Angeline Stickney Hall: from "An Astronomer's Wife" by Angelo Hall (1908), via Internet Archive MMX spacecraft illustrations, Idefix, Shoemaker–Levy 9 and all diagrams: our own illustrations, not photographs. Orbi: Orbi Observatory. Music and sound: original score made for Orbi Observatory.