TON 618 Is Lighter Than The Air. That's Not The Strange Part...

TON 618 is one of the most massive black holes we know of: tens of billions of times the mass of the Sun, with an event horizon about 27 times wider than Neptune's orbit. And yet, on average, it's less dense than the air you're breathing right now. That's not the strange part. In this video we follow that number from a country parson's "dark star" of 1784 to the tides on a beach, and find out what it really measures: how much gravity changes between your head and your feet at the edge. At the horizon of TON 618 that difference is about a trillionth of Earth's gravity. You could cross the most absolute boundary in the universe and feel nothing at all. Everything here is the simplest kind of black hole: one that doesn't spin, with the quasar's blazing gas stripped away. The view of the fall is a real calculation of how a black hole bends light, rendered by us over a panorama of the Milky Way; the black hole picture at the start is our own artist's impression. CHAPTERS 0:00 The famous picture 1:06 Weighing the invisible 2:25 How big is a black hole? 2:45 Michell's dark star 4:18 Thinner than air 5:40 A difference in pull 7:21 The gentlest edge 8:40 Falling 10:26 Nothing told you 11:08 The river of space 12:31 The center is a moment 13:06 The countdown 14:25 The strange part SOURCES & CREDITS Full list of sources, data and images in the pinned comment. Key sources: Shemmer et al. (2004, ApJ) · Ge et al. (2019, AJ) · Bentz et al. (2013, ApJ) · Michell (1784, Philosophical Transactions) · Hamilton & Lisle (2008, American Journal of Physics) · Lewis & Kwan (2007, PASA) · Event Horizon Telescope Collaboration (2019, 2022) Data: NOAA Tides & Currents (Boston tide gauge) · Bentz et al. (2013) Images: ESO/S. Brunier (Milky Way panorama, CC BY 4.0) · EHT Collaboration (M87* and Sgr A*, CC BY 4.0) · ESA & NASA (M101, CC BY 4.0) · Sloan Digital Sky Survey · NASA · Internet Archive (Galileo, 1638; Newton, 1728) · Lucien Chavan (Einstein, 1904) Footage: NASA · Pexels (Taryn Elliott, Rholdan Ortiz, K, Nirav Shah, nis_vagabond) Animations: original work by APORIA. #TON618 #BlackHole #Astrophysics