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Short Summary
Main recommendation: The largest single body in the universe is the ultramassive black hole TON 618, estimated at 66 billion solar masses; since it is seen as it looked 10 billion years ago, it may actually be even larger now. The video ranks black holes from primordial ones (hypothetical) through stellar, supermassive, and ultramassive types, showing how size grows with mass and how black holes can grow indefinitely.
Key Points
- Primordial black holes may have formed just after the Big Bang; the smallest that could survive would be about a trillion kilograms (a mountain's mass) yet no bigger than a proton. They have not been observed and may be dark matter.
- Stellar black holes form from violent events like neutron star mergers or massive star core collapses; the smallest known has 2.7 solar masses and is about 16 km across.
- The black hole mass scale shows a curious gap: black holes up to about 150 solar masses are common, then nothing until black holes millions of times more massive, suggesting a different growth process for supermassive ones.
- Supermassive black holes sit at galaxy centers, but they contain only about 0.001% of their galaxy's mass; dark matter, not the black hole, mainly binds the galaxy's stars together.
- Ultramassive black holes such as the one in OJ 287 (18 billion solar masses) could comfortably fit three Solar Systems side by side inside of it.
Details Worth Noting
- Concrete instructions: No step-by-step instructions, checklists, or actionable advice are given; the video is an informational ranking.
- Quasi Stars are a hypothetical concept in which very dense early-universe stars could collapse into black holes several thousand solar masses in size, possibly seeding supermassive black holes; their existence is unconfirmed.
- Size estimates depend on uncertain mass measurements from Kepler's Laws and the Schwarzschild equation, which assumes non-spinning, perfectly round black holes; the presenters admit the ranking is approximate.
- Sagittarius A*, the Milky Way's central black hole, has about 4 million solar masses and a radius about 17 times the Sun's.
- Cygnus A's supermassive black hole (2.5 billion solar masses) would swallow all planets if placed where the Sun is, and its radio lobes span half a million light-years, about 2.5 Milky Ways wide.
- Only a couple dozen black holes have reliable data, since black holes cannot be seen directly.
Bottom Line
Black holes have no upper size limit, and the largest known, TON 618, is so massive that its true scale is uncertain, making any ranking approximate.
