This is what we astronomers call a blob, or a  smudge, if you want to get really technical.

It may not look like much from here, but  what do you expect for something near the   literal edge of the observable universe.

If  you were there when this light was emitted,   you’d A. be at the beginning of time, and B.  be looking at an entire galaxy containing an   enormous black hole at its heart.

It’s the  most distant black hole we’ve semi-directly   detected.

That’s cool enough on its own, but  as an added bonus this one smudge may have   solved the mystery of the origin of the  supermassive black holes in our universe.

Introducing Abell 2744.

It’s a giant cluster  of galaxies around 4 billion light years   away.

Basically our back yard,  cosmologically speaking.

The most   interesting thing about Abel 2744—at least for  us today—isn’t what’s in the cluster itself,   but what’s behind it.

The cluster lives  in a vast halo of dark matter that warps   space across its 4-million-light year span.

Light from distant objects traveling through   the cluster is deflected and magnified.

The  cluster is a stupendous gravitational lens that   enables us to see much further than our puny  human-made telescopes would normally allow.

That’s why the Hubble Space Telescope studied Abel  2744 in detail, and why it was one of the early   must-dos for the James Webb Space Telescope.

And this is where our smudge got interesting.

JWST observes deep into infrared wavelengths, and  showed that the object has IR colours consistent   with a galaxy whose normally visible light has  been stretched out by the expanding universe,   increasing or redshifting its wavelength by a  factor of over 10.

Higher redshift means larger   distance, and a redshift of 10.1 means this light  has been traveling for around 13.2 billion years,   coming to us from a time near the beginning of  time, when the universe was less than 3.5% its   current age.

That earned our smudge the name  UHZ1, for ultra-high redshift galaxy number   one—where the z is the symbol for redshift.

That’s cool, but JWST has now found galaxies   quite a bit more distant than this.

The really  exciting moment came when we pointed another   orbiting satellite at the smudge.

This is the  image by the Chandra X-ray telescope.

It turns   out there are a LOT of X-rays coming from this  little blob.

Now X-rays are much harder to bring   to a sharp focus so the 4 pixels of X-ray light  aren’t coming from across this spread-out region,   but rather from somewhere inside this region.

There’s really only one known way for a galaxy to   be blasting out X-rays at this level, and that’s  by harboring a quasar.

To refresh your memory,   a quasar is when the supermassive black  hole—the SMBH—that lives at the center of   every galaxy starts feeding.

As matter swirls  towards the black hole it’s superheated until   it outshines the entire surrounding galaxy.

And just before it reaches the black hole,   conditions get so crazy that the space outside  the black hole glows bright with high-energy   X-rays.

Based on the amount of X-ray light and  the distance, we can estimate that the black hole   must be 40 million times the Sun’s mass.

That’s  10 times the mass of the Milky Way’s own SMBH.

UHZ1 is the most distant quasar ever  discovered, which also makes it the   earliest known quasar and so the earliest  black hole that we actually have evidence for.

So with that out of the way, let’s get to the  good stuff.

To understand why UHZ1 is so exciting,   you have to understand one of the biggest debates  in cosmology - the origin of supermassive black   holes.

Essentially every galaxy in the modern  universe has at its core a black hole that’s   100,000 to several billion times the mass of  the Sun.

We also see much smaller black holes—so   called stellar black holes—that can be in the  rough range of 10 to 100 solar masses.

Oddly,   we don’t see black holes in the middle range of  100 to 100,000.

We’ll come back to why that’s odd.

Now, we know how to make stellar  black holes—they’re what you get   when the core of a massive star collapses  on itself after the star dies.

So how do   you make a supermassive black holes  grew?

That’s the big question.

It   could be they grew from the very first  stellar corpses in the early universe,   gulping down gas and merging with other black  holes for billions of years to reach their current   enormous sizes.

But over the last decade or so,  as we looked to greater and greater distances,   we started to find quasars shining out from the  first billion years of cosmic time—quasars powered   by supermassive black holes that should  not have had enough time to get that big.

There are two potential solutions to this  conundrum.

Either the black holes started   small and grew way, way faster than we thought  they could.

Or they started much bigger than   the black holes that form in stellar deaths in  the modern universe.

These are the small seed   and heavy seed models respectively.

UHZ1  is going to help us choose between them.

Let’s start with the small seed model.

Can a  stellar corpse grow into a quasar engine in   less than a billion years?

Well, it’s tricky.

There’s a limit to how fast a black hole can   feed even with an endless supply of gas.

As  gas spiraling into a black hole heats up,   it blasts out radiation which pushes  on the infalling gas and counters the   black hole’s gravity.

Bigger black  holes can eat more and radiate more,   but there’s always an approximate upper limit  that increases with that mass—it’s called the   Eddington limit.

You can calculate how big a  black hole would grow feeding at this maximum   rate for a billion years—and the a nswer is …  not big enough to explain those early quasars.

That said, there are various tricks we can  include to make the small seed model work.

There are scenarios in which black holes  can feed faster than the Eddington limit,   although they still need to feed non-stop to  reach supermassive status so quickly—which   itself is a problem.

Or you can form a lot of  black holes close to each other and have them   merge very quickly.

Or you can start out with  really, really big stars leaving behind black   holes that are maybe 100 or even 1000 times larger  than are produced today.

In the modern universe,   all the heavy elements released in past supernovae  cause gas clouds to fragment as they collapse,   leading to smaller stars.

But the  pristine hydrogen and helium that   filled the universe at the beginning  held together as it collapsed, probably   leading to gigantic stars and commensurately  massive, but still not supermassive black holes.

With a combination of these tricks—fast and  consistent feeding and biggish stellar black   hole seeds—it’s possible to make supermassive  black holes in under a billion years.

This   still doesn’t explain why we don’t see any  black holes in the 100 to 100,000 solar   mass range.

If SMBHs grew from stellar black  holes by passing through this range then you’d   expect some stragglers to still be in that  range, but that doesn’t seem to be the case.

OK, so let’s try the heavy seed model.

What if  the seeds of supermassive black holes weren’t   even born from the hyper-dense cores of dead  stars?

In fact it's actually a misconception that you   need extremely dense matter to make a black hole.

For any given mass, there’s a particular size that   mass needs to be crushed into in order for it  to form a black hole.

This is the Schwarzschild   radius.

For the Sun, it’s around 3 km, and a  solar mass crammed within that radius would   have the same density as a typical 3000 meter  tall mountain crammed into a cubic centimeter.

On the other hand, a typical chonky  supermassive black hole of a billion   solar masses has a Schwarzschild radius  the size of Neptune’s orbit.

A billion suns   crammed into that region would have the  density of … cotton candy.

That’s right,   fill a solar system with cotton candy and  you’d get an instant giant black hole.

The early universe did not contain  significant quantities of cotton candy,   as far as we can tell anyway.

But it  was filled with a lot of gas that would   later form stars and galaxies.

As that gas  started to collapse to make those things,   the resulting protogalactic clouds may have  had cores dense enough to collapse directly   into black holes without ever forming a star.

Again, this only works in the early universe   where the unpolluted hydrogen and helium  doesn’t tend to fragment as it collapses.

And as it happens, theoretical calculations  of the expected sizes of these direct collapse   black holes are right around 100,000  solar mass mark.

That gives us a way to   go straight from gas to the smallest SMBHs  without having to grow from stellar seeds   through the intermediate range.

And once you  have a small SMBH, a pretty sensible rate of   feeding can turn it into a large SMBH  in mere hundreds of millions of years.

OK, great.

Between our two models - small  versus heavy seed, it’s looking like the   heavy seed model feels more plausible.

So let’s see what our new player—UHZ1—has to say about this.

Previous record holders for most distant quasar,  like J1342+0928, J0313–1806, and J1007+2115,   are all similarly massive, and they had already  put the ‘small seed’ formation theory under a   lot of stress in the past few years.

But they  were all found right around 700 million years   after the big bang—just on the boundary of the  amount of time needed to grow a small seed,   assuming some very creative astrophysics  to allow a really cosmic bulking phase.

But UHZ1 shaves 200 million years of the  allowed growth time.

If it was marginally   plausible to grow a small seed into an SMBH  before, now it’s feeling nearly impossible.

Let’s look a bit more closely at this object  to try to make this more concrete.

Based on   the JWST images, we can get an idea of the amount  of starlight versus quasar light in this object.

Even those images are dominated by quasar  light.

The galaxy has around 40 million   Suns worth of mass in stars, (the same as it's mass in the black hole) and that's around 1000  times less than the stars in the Milky Way.

This isn’t   unusual in itself.

We expect galaxies from  so long ago to still be building up mass and   converting gas into stars.

But for most of  the universe’s history we see a pretty tight   correlation between the number of stars in  a galaxy and the mass of its central black   hole.

That has been taken by some to indicate  that galaxies and their central black holes   grow together in relative lock-step.

UHZ1  suggests otherwise—it tells us that the   black hole starts relatively enormous  and then the stellar mass catches up.

UHZ1 may represent the first in a new class of  object called an OBG - for overly-massive black   hole galaxy, or outsized black hole galaxy.

OBGs  are objects hypothesized to exist in the early   universe in which the black hole and stellar  masses were around the same.

The amount of   infrared and X-ray light coming from UHZ1 is  consistent with simulations of OBG formation,   so maybe this class of object is  no longer hypothetical.

If so,   that tells us a lot.

OBGs only work  if their central black hole is formed   by direct collapse, not through  the growth of a stellar remnant.

Overall, things are looking pretty  good for the heavy seed model, and   quite a bit less good for the small seed model.

But it’s not quite a smoking gun.

For example,   maybe UHZ1 is weird.

Perhaps its SMBH  formed in an unusual way—for example,   from a rare and massive primordial black hole or  in an exotic environment like a quasistar.

But   the fact that observations of UHZ1 line up so well  with the direct collapse and the OBG model would   tend to disfavor these alternate explanations,  at least in UHZ1s case.

And even if UHZ1 is an   OBG it doesn’t mean other supermassive black  holes couldn’t have formed from small seeds.

But in general the case for the latter as an  important source of SMBHs is being whittled away.

So what’s next?

Well, we keep  looking.

UHZ1 is the first of its   kind.

But in astronomy where there's one, there's often many and hopefully soon we'll find the many.

As JWST and Chandra continue their  good work, we’ll develop a clearer and   clearer picture of what the earliest times  were like as we discover more distant   glimmers of the earliest stars and quasars  that first lit up a newly-born spacetime.