UY Scuti: This Star Could Swallow the Entire Solar System

If you found this interesting, please subscribe:    / @mystraltv   This video explains the largest known stars in the universe, including UY Scuti and Stephenson 2 DFK 1, how astronomers measure their true size, and what these stellar giants reveal about the future of our own Solar System. The video follows the scientific story behind two of the most enormous stars ever studied, beginning with nineteenth-century observations and ending with modern measurements from Gaia, the Very Large Telescope, and other observatories. It explains why the famous size of UY Scuti has been repeatedly revised, why Stephenson 2 DFK 1 may challenge the limits of stellar physics, and how astronomers recently witnessed a star engulfing one of its own planets for the first time. The video also explores how dying stars evolve into red supergiants, why measuring their true size remains difficult, and what these discoveries imply for the long-term fate of the Sun and Earth. *What’s covered in this video:* The nineteenth-century German star catalog that first recorded UY Scuti as an ordinary faint star before astronomers understood its extraordinary scale. The location of UY Scuti in the constellation Scutum near Gamma Scuti and the Eagle Nebula, hidden behind dust within the Milky Way’s Zone of Avoidance. Why UY Scuti appears faint despite being one of the largest known stars, and how its semiregular 740-day pulsation reveals its changing outer atmosphere. The 2012 observations with the European Southern Observatory’s Very Large Telescope in Chile that measured UY Scuti alongside AH Scorpii and KW Sagittarii using stellar interferometry. What the original estimate of 1,708 solar radii meant for our Solar System, placing Mercury, Venus, Earth, Mars, the asteroid belt, and Jupiter inside the star. How red supergiants form as massive stars exhaust hydrogen, begin helium fusion, and expand into enormous but fragile stellar envelopes. The Hayashi limit developed by Chushiro Hayashi and why stellar evolution predicts that stable red supergiants cannot exist beyond a theoretical temperature boundary. Why UY Scuti is continuously losing mass, producing water, silicon monoxide, and hydroxyl masers while surrounding itself with a dense shell of gas and dust. How the Gaia space observatory fundamentally changed estimates of UY Scuti’s distance, radius, luminosity, and status as the largest known star. Why newer studies reduced UY Scuti’s estimated size while still leaving it large enough to engulf the inner Solar System. The discovery of Stephenson 2 and the remarkable red supergiant known as Stephenson 2 DFK 1, also called Stephenson 2-18. Why Stephenson 2 DFK 1 may exceed 2,150 solar radii, potentially extending beyond Saturn’s orbit if placed at the center of our Solar System. The debate over whether Stephenson 2 DFK 1 truly belongs to the Stephenson 2 star cluster and why uncertainty in its distance affects every size estimate. How astronomers define the Rosseland radius when measuring stars that have no clear physical surface separating them from surrounding space. Other candidates for the largest known star, including VY Canis Majoris, VX Sagittarii, MY Cephei, WOH G64, and NML Cygni. The 2020 discovery by the Zwicky Transient Facility of ZTF SLRN-2020, the first directly observed case of a star engulfing a Jupiter-sized planet. How observations from the Keck Observatory, NEOWISE, and researchers including Kishalay De revealed the first confirmed stellar planetary engulfment. The 2026 study of TOI-5882 showing unusually high lithium levels as evidence that the star likely consumed one of its own planets. Why Brooke Kotten and colleagues linked planetary engulfment to chemical signatures and the gravitational influence of a nearby brown dwarf. What these discoveries reveal about the future evolution of the Sun into a red giant and the likely fate of Mercury, Venus, Earth, and the rest of the inner Solar System. Mentioned in this video: UY Scuti, Stephenson 2 DFK 1, Stephenson 2-18, Stephenson 2, Scutum, Gamma Scuti, Eagle Nebula, Milky Way, Zone of Avoidance, Very Large Telescope, European Southern Observatory, Atacama Desert, Chile, AH Scorpii, KW Sagittarii, Gaia, Chushiro Hayashi, Hayashi limit, red supergiant, hypergiant, Wolf-Rayet star, luminous blue variable, Rosseland radius, water masers, silicon monoxide masers, hydroxyl masers, Charles Bruce Stephenson, Davies, Deguchi, Humphreys, VX Sagittarii, MY Cephei, VY Canis Majoris, WOH G64, Large Magellanic Cloud, NML Cygni, California Institute of Technology, Zwicky Transient Facility, Kishalay De, Keck Observatory, MIT, NEOWISE, ZTF SLRN-2020, Nature, TOI-5882, Brooke Kotten, University of Michigan, Arizona, brown dwarf, Mercury, Venus, Earth, Mars, Jupiter, Saturn, asteroid belt, Solar System, stellar evolution, planetary engulfment, supernova, stellar interferometry.