The Biggest Stars In The Universe Explained in 10 Minutes

The smallest star we know is about the size of Saturn. The biggest would reach all the way out to Saturn's orbit. So we shrank the Sun down to a basketball and lined up every star next to it, from the smallest to the biggest: a star barely heavy enough to shine, Barnard's Star, Vega, Capella, Polaris, Deneb and Antares, the fallen champion UY Scuti, the peanut-shaped HR 5171 A, WOH G64 in another galaxy and Stephenson 2-18, the biggest star we know. And finally the monster stars of the early universe, which might have swallowed the whole solar system. Giant stars don't have a sharp edge, so their sizes are estimates, and the video says where astronomers disagree. The basketball-scale comparisons are our own rounded calculations from the published sizes. #space #astronomy #stars 0:00 Intro: the Sun as a basketball 0:23 The smallest star: EBLM J0555-57Ab 1:12 The racing star: Barnard's Star 2:00 The squashed star: Vega 2:47 The double giant: Capella 3:33 The North Star: Polaris 4:15 The faraway giant: Deneb 4:56 The rival of Mars: Antares 5:47 The fallen champion: UY Scuti 6:42 The peanut star: HR 5171 A 7:28 The giant from another galaxy: WOH G64 8:20 The biggest star we know: Stephenson 2-18 9:07 The monster stars: the biggest stars that ever lived 10:05 Which star would you want to see up close? Sources Smallest star ever discovered, EBLM J0555-57Ab (Cambridge, 2017): https://www.cam.ac.uk/research/news/smallest-ever-star-discovered-by-astronomers Brown dwarfs: the hydrogen-burning limit: https://en.wikipedia.org/wiki/Brown_dwarf Barnard's Star: distance, size, proper motion: https://en.wikipedia.org/wiki/Barnard%27s_Star Four tiny planets around Barnard's Star confirmed (2025): https://www.sciencedaily.com/releases/2025/03/250311154117.htm Vega is a rapidly rotating, pole-on star (Aufdenberg et al. 2006): https://arxiv.org/abs/astro-ph/0603327 Vega, the first star photographed after the Sun (1850): https://en.wikipedia.org/wiki/Vega Capella revisited: two giant stars (Torres et al. 2015): https://arxiv.org/abs/1505.07461 The spotted surface of Polaris (CHARA, 2024): https://www.sciencedaily.com/releases/2024/08/240820124556.htm Deneb: size, distance, luminosity: https://en.wikipedia.org/wiki/Deneb Antares: https://en.wikipedia.org/wiki/Antares Best map of a distant star's surface: Antares (ESO, 2017): https://www.eso.org/public/news/eso1726/ UY Scuti: size revised with Gaia distances: https://en.wikipedia.org/wiki/UY_Scuti Largest yellow star ever found, HR 5171 A (ESO, 2014): https://www.eso.org/public/news/eso1409/ First close-up picture of a star outside our galaxy, WOH G64 (ESO, 2024): https://www.eso.org/public/news/eso2417/ WOH G64: a transition to a yellow hypergiant?: https://arxiv.org/abs/2411.19329 ...and the debate about it: https://earthsky.org/space/one-of-the-biggest-stars-in-the-universe-getting-ready-to-explode/ Stephenson 2-18: https://en.wikipedia.org/wiki/Stephenson_2-18 Red supergiants around the cluster Stephenson 2 (Negueruela et al. 2012): https://arxiv.org/abs/1208.3282 Monster stars in the early universe: nitrogen in GS 3073 (Nandal et al. 2025): https://www.space.com/astronomy/james-webb-space-telescope/james-webb-space-telescope-finds-1st-evidence-of-dinosaur-like-stars-in-the-early-universe How big rapidly growing supermassive stars get (Hosokawa et al. 2013): https://arxiv.org/abs/1308.4457