What If the Sun Disappeared? Earth's First Week, Hour by Hour

Right now, at this exact second, the Sun is gone. For the next 8 minutes and 19 seconds, nobody on Earth can tell. Then two things happen at the same moment: the light goes out, and Earth leaves its orbit. This is the first week without the Sun, told on a clock. Why gravity takes as long as light to "notice" (and how we measured that in 2017). Why Earth doesn't fall anywhere. Why the city lights stay on. Why the cold, not the dark, is the real problem, and why the ocean holds out far longer than the land. And where Otto is on day seven. This can't literally happen: a star can't just vanish. We treat it as a thought experiment and follow the physics. Chapters 0:00 The Sun is gone 0:29 Does gravity move at the speed of light? 1:51 +8 min 19 s: two things at once 3:21 +1 hour: the city stays lit 4:53 +24 hours: the cold begins 6:03 Day 3: how cold, exactly? 7:36 Day 7: one week after 9:11 The strangest part What's estimated, and what's disputed • Temperature in week one is the big open question. We found no published study that simulates this scenario. A Caltech planetary scientist (D. Stevenson, 1999) estimated the surface would drop below the freezing point of seawater within days to a week. Popular articles turned that into "0°F everywhere in a week", which is not what he wrote. Our own rough energy estimate says the upper ocean takes months to freeze, not days. Treat every week-one temperature as an estimate. • Our own calculations from NASA data: the 8 min 19 s (average Earth–Sun distance; it varies from about 8:11 to 8:27 over the year), the distance Earth covers in a week and in a year, the oxygen figure, and the 0.03%. • When Mars, Jupiter and Saturn go dark is our own approximation and depends on where the planets are that day. • "Ten thousand times more power than humanity uses" depends on the estimate for world energy use (about 18 TW), so it's rounded. • The ~170,000 years for light to leave the Sun's core is one model estimate; published figures range from tens of thousands to hundreds of thousands of years. • The one-year and thousand-year figures, the grain reserves (FAO forecast, as reported) and the Iceland and survival quotes come from single sources and are attributed as such in the video. Sources • NASA, Sun Facts. https://science.nasa.gov/sun/facts/ • NASA NSSDC, Earth Fact Sheet (distance, orbital speed, solar irradiance, mass of the atmosphere). https://nssdc.gsfc.nasa.gov/planetary... • B. P. Abbott et al. (LIGO, Virgo, Fermi-GBM, INTEGRAL), "Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A", ApJL 848:L13 (2017). https://arxiv.org/abs/1710.05834 • M. Kuchner (NASA Goddard), Ask Astro, Astronomy (2012). https://www.astronomy.com/science/if-... • Physics Van, University of Illinois, on why the Sun can't just vanish. https://van.physics.illinois.edu/ask/... • Physics Van, University of Illinois, on the Moon staying with Earth. https://van.physics.illinois.edu/qa/l... • Ember, Global Electricity Review 2026. https://ember-energy.org/latest-insig... • C. B. Field et al., Science 281:237 (1998), ocean primary production, via BioNumbers. https://bionumbers.hms.harvard.edu/bi... • NASA/JPL, Ocean Connection (top 3 m of ocean vs. the atmosphere). https://sealevel.jpl.nasa.gov/files/o... • J. H. Davies and D. R. Davies, "Earth's surface heat flux", Solid Earth 1:5 (2010). https://se.copernicus.org/articles/1/... Single-source estimates quoted in the video • D. Stevenson, Caltech Question of the Month (1999). https://experts.caltech.edu/news/calt... • H. Otterbein, "If The Sun Went Out, How Long Would Life On Earth Survive?", Popular Science. https://www.popsci.com/science/articl... • Mitalas & Sills (1992) photon travel time, via Futura-Sciences. https://www.futura-sciences.com/en/th... • FAO cereal forecast 2025/26, as reported by WAM. https://www.wam.ae/en/article/15szklt...