What If the Sun Went Out for a Day?

It's midday. Blue sky. And then the Sun switches off... but for 8 minutes and 20 seconds, absolutely nothing happens. What would really happen if the Sun went out for a whole day? Would Earth instantly freeze? Would we run out of oxygen? Would Earth fly off into space? The Sun can't really switch off, so here are our rules: its light and heat stop for exactly one day, but its mass stays put, so its gravity works as normal and Earth stays in orbit. We use NASA, NOAA, the Met Office's eclipse data and peer-reviewed research. On screen, SOURCE marks confirmed facts, ESTIMATE marks published or calculated numbers, and BEST GUESS marks our speculation. Spoiler: the sky goes black, the Moon goes dark, it gets cold (especially inland), solar power stops and satellites struggle. But Earth doesn't freeze in a day, the air doesn't run out, and we don't fly off into space. Every source is listed below. CHAPTERS 0:00 The Sun switches off 0:10 Welcome to The If Factory 0:19 The rules: light off, gravity on 0:35 Step 1: the 8 min 20 s delay 0:49 The sky turns black 0:59 The Moon goes dark too 1:13 Myth check: would Earth instantly freeze? 1:25 How fast would it get cold? 1:37 The longest winter night 1:57 The oceans barely notice 2:10 Weird weather 2:23 Step 2: plants and photosynthesis 2:38 Myth check 2: would we run out of oxygen? 2:52 Silent bees 3:04 What about us? 3:18 Step 3: solar power stops 3:31 Can the grid cope? 3:46 Step 4: satellites 4:06 The big one: gravity 4:19 Myth check 3: would Earth fly off? 4:43 The Sun switches back on 4:57 So, would we survive? 5:14 Sources SOURCES Light and the sky: BBC Sky at Night, how long light from the Sun takes to reach Earth (8 min 20 s on average): https://www.skyatnightmagazine.com/sp... NASA Science, sunlight takes about 8 minutes to reach Earth: https://science.nasa.gov/big-idea-3-2... NASA Space Place, why is the sky blue?: https://spaceplace.nasa.gov/blue-sky/ NASA, Earth's Moon (moonlight is reflected sunlight): https://science.nasa.gov/moon/ Heat and temperature: NOAA JetStream, the ocean (top 10 ft holds more heat than the whole atmosphere): https://www.noaa.gov/jetstream/ocean NASA Earth Observatory, Climate and Earth's energy budget (~240 W/m² emitted): https://earthobservatory.nasa.gov/fea... Clark (2016), near-surface temperature anomalies in the 20 March 2015 eclipse, 266 UK sites (Phil. Trans. R. Soc. A): https://royalsocietypublishing.org/rs... Hanna et al. (2016), meteorological effects of the 20 March 2015 eclipse, Met Office station data (Phil. Trans. R. Soc. A): https://pmc.ncbi.nlm.nih.gov/articles... Life: Graf et al. (2010), circadian control of starch use at night in Arabidopsis (PNAS): https://www.pnas.org/doi/full/10.1073... Galen et al. (2018), bees go silent during the 2017 total solar eclipse (Annals of the Entomological Society of America): https://doi.org/10.1093/aesa/say035 Power and satellites: Ember, Global Electricity Review 2025 (solar 6.9% of world electricity in 2024): https://ember-energy.org/latest-insig... NESO, GB solar record 15.4 GW, 23 April 2026: https://www.neso.energy/britains-elec... Saft / EUMETSAT, Meteosat Third Generation batteries (geostationary eclipses up to 72 minutes a day): https://saft.com/en/media-resources/p... ESA, Meteosat Second Generation (equinox eclipse seasons): https://www.esa.int/Applications/Obse... Gravity: NASA NSSDC, Earth fact sheet (orbital speed 29.78 km/s): https://nssdc.gsfc.nasa.gov/planetary... LIGO/Virgo, GW170817: gravitational waves from a binary neutron star merger: https://dcc-lho.ligo.org/public/0145/... Figures that vary: light takes between about 8 min 10 s and 8 min 27 s through the year. "About two degrees" of average air cooling, "a tenth of a degree" for the oceans, "around two thousand years" of oxygen and Jupiter staying lit "for more than an hour" are our own rough arithmetic, and "ten to twenty degrees colder inland" is our best guess, not a climate-model result. The 4 °C drop was the largest seen at UK stations in the 2015 eclipse; the typical drop was about 1 °C. HOW THIS VIDEO WAS MADE The narration is a synthetic (text-to-speech) voice: Kokoro TTS, British voice "bf_emma". All visuals are drawn in code, with no AI-generated images. UK map: Natural Earth (public domain). Music and sound effects were synthesised in code for this channel. What should Iffy switch off, flood or freeze next? Tell us in the comments. #theiffactory #whatif #sun #space #science