Supermassive black hole
TON 618
One of the most massive black holes ever documented, powering an extraordinarily bright quasar first catalogued in 1957, decades before its true nature was understood.
About TON 618
TON 618 isn't a galaxy in the usual sense — it's a quasar, an extremely bright, distant object powered by a black hole devouring huge amounts of surrounding gas. Its brightness is estimated at roughly 140 trillion times that of our Sun, bright enough to be detected from over 10 billion light-years away. Because such distant black hole masses are measured indirectly — from the width of light emitted by gas swirling near the black hole — different measurement techniques have produced mass estimates ranging from about 40 billion to 66 billion solar masses. Even at the lower end of that range, it remains one of the most massive black holes ever documented.
Interesting facts
- TON 618 is surrounded by a Lyman-alpha blob — a glowing cloud of hydrogen gas roughly 330,000 light-years across, more than twice the width of the Milky Way.
- It was catalogued in 1957 as a faint blue point of light, decades before astronomers understood that quasars were powered by black holes.
- Mass estimates for objects this distant carry real scientific uncertainty — different studies using different emission lines have produced answers that differ by nearly a factor of two.