The Oldest Black Hole Ever Found May Unlock Mysteries About the Universe's Birth

discoveries never cease. Just when you think we've found the oldest fossil,
animal, or planet, there's another research team announcing that they've found
one even older. Even still, the discovery of the oldest known black hole is
pretty impressive: it formed just millions, not billions, of years after the
Big Bang.

And because
we know it's there, we can learn about the conditions of the universe when it
formed. About 13.8 billion years ago, our universe existed as a singularity: a
point of infinite gravity and density where the laws of physics break down.
(What happened before that is up for debate). Then, in trillionth of a second,
all hell broke loose. The singularity exploded, doubling in size many times
over at a rate faster than the speed of light in an event we know as the Big

That early
universe looked very different than it does today. It was a dense plasma soup
that was positively buzzing with subatomic particles, including photons (light)
that scattered off of free electrons. At first, the universe was too hot for
atoms to form, but it eventually cooled enough to form hydrogen (and eventually
helium) atoms that were ionized, or missing an electron. Those atoms attracted
electrons to become neutrally charged, allowing light to travel freely for the
first time (and creating what we know as the cosmic microwave background). But
that freedom was short lived, because the neutral atoms eventually formed a
"cosmic fog" that absorbed the light, marking the start of what
scientists call the Dark Ages of the early universe.

Even once
the earliest stars began to form, this fog would have snuffed out their light
and kept the universe pitch black. Eventually, around 400 million years after
the Big Bang, there were enough young stars and quasars — the bright jet of
light blasting out of a black hole — to create enough ultraviolet light to
strip those atoms of their electrons once again in an event called "reionization."
That gradually burned off the fog, returning the universe to the light-filled
state it had been in before the Dark Ages. But this time, the light wasn't just
the Big Bang's leftovers. It was in constant production, thanks to a young
generation of stars. By the end of reionization, 1 billion years after the Big
Bang, the fog was completely gone and the universe had gone from opaque to
transparent. Let there be light ... again!

That's the
gist of what astronomers think happened in the early universe. But that story
is full of holes. We still don't know when the first stars formed, or which
light sources were responsible for reionization and why. But thanks to the laws
of physics, it's possible to look back in time. You see objects in the sky not
as they are, but in the state they were in when the light began traveling to
you. It takes the light from the sun eight minutes to reach you, so the sun you
see is actually eight minutes in the past. Proxima Centauri, our closest star,
is about four light-years away, so you see it four years in the past. Our
universe is a little more than 13 billion years old, so if by some miracle we
could see something 13 billion light-years away, we could glimpse the beginning
of the universe itself.

That's why
the discovery of this ancient black hole is so groundbreaking. Because of its
distance, we know that it formed 690 million years after the Big Bang: right in
the middle of reionization. In fact, the gas around this black hole and its
telltale quasar is half neutral, half ionized, just as you'd expect from that
era. The black hole is much bigger than you'd expect, however, at 780 million
times the mass of our sun. It didn't have enough time to grow to that size, and
scientists are puzzling over how that was possible. One theory? It just started
bigger, possibly because collapsing clouds in the early universe gave birth to
supersized black holes.

technology is making discoveries about the universe come at breakneck speed.
The researchers, led by astronomer Eduardo BaƱados, hope to discover more black
holes and quasars like this one, and hopefully solve the new puzzles this
discovery has posed.