how are supermassive black holes formed

How are supermassive black holes formed?  Although science is sure supermassive black holes exist, no one really knows how they start.

There are theories, but the idea that each is a stellar black hole that somehow grew to ginormous proportions is pretty much debunked.

But, that leaves people with questions, including, “how supermassive black holes are formed?”

It is not clear but supermassive black holes may be formed because of core-collapse supernovae, capture of nearby gas and matter, and galactic collisions. 

The Big Bang and Its Connection with Supermassive Black Holes

big bang's connection with supermassive black holes

A stellar black hole and a supermassive black hole might be two distinct phenomena. But, they have opened up new lines of scientific enquiry.

However, even the latest supercomputers are struggling to model the complete life cycle of stars.

And it also includes what happens after the star collapses during the millions and billions of years after its death. Scientists are not sure about when these holes formed.

They believe there was not enough time after the Big Bang some 13.7 billion years ago for the relatively very tiny stellar black holes to form.

And it was certainly weird for them to have time to devour enough gas and matter to grow to the point of being supermassive.

The Types of Black Holes and Their Formation

types and formation of black holes

Scientists believe there must be at least two kinds of black holes:

  • The stellar-mass which is between 5 and 10 times the mass of the Sun
  • The supermassive that is millions if not billions of times more massive

With the aid of high-tech telescopes capable of seeing the universe way back in time, scientists have found out that there are supermassive blackholes at the center of every large universe. 

More about Supermassive Black Holes in Our Universe

supermassive black holes in our universe

Ours is called Sagittarius A*, and has a mass equal to 4 million Suns.

It may be small compared to some but being one of potentially four types of black hole and emitting no light, it’s impossible to see despite its huge size.

It could hold millions of planets the size of the Earth.

However, because scientists have come to doubt that supermassive black holes could form even when a very large star goes supernova, they are considering other theories

Quasars as Indicators of Supermassive Black Holes

quasars as indicators of supermassive black holes

Quasars are star-like objects powered by the high-velocity gas spiraling into nearby black holes.

They are one of the most luminous objects in space, visible at distances in the billions of light years.

There are jets of energy bursting from either side of the object making quasars somewhat distinctive.

However, there is speculation that what we are actually looking at is a black hole from a different point of view

What Scientists Believe about Quasars?
what scientists believe about quasars

With Hubble and closer clearer observations most scientists now believe it is black holes that power quasars.

Hubble measured the velocity of the streaming matter making it possible to work out the black hole’s mass.

But, more importantly, Hubble confirmed the theory that black holes and supermassive black holes form at the center of most galaxies.

Also, they can sometimes be comparatively small and also confirmed that it is the larger galaxies that have the larger black holes

How Are Supermassive Black Holes Formed?

formation process of supermassive black holes

Scientists have different theories about the formation of supermassive black holes.

Here are some possible explanations: 

Core Collapse Supernovae and Black Hole Formation

It is true that there are theories surrounding the formation of supermassive black holes.

But, scientists are confused as to why there should be such a difference in size.

These days, the attention has shifted to using super telescopes to search the missing intermediate sized along with primordial black holes, hypothesized to form in the very first micro-seconds. 

Do they exist, we don’t know, but for a long time all blackholes were speculation but now, how stellar-mass black holes form is known and understood 

The Process of Forming Stellar-Mass Black Holes

the process of forming stellar-mass black holes

It happens to large stars with masses 8 times the sun as they run out fuel and their cores collapse, rebound and explode in a supernova.

The process leaves behind a super dense neutron star.

When a star exceeds 20 times the mass of the sun and the core collapses the result is a black hole. It’s big but not supermassive.

One theory suggests that to be that big takes 100 times the mass of the Sun. 

Accretion Disks and Their Role in Black Hole Growth

accretion disks and black hole growth

Technology allows scientists to see further and further back in time, but we can still barely see how active the early universe was.

Here is what they have found:

Black hole visibilityHard to spot on its own but affects the matter around it.
Accretion materialThe matter around a black hole with potential to release energy.
Material gatheredA black hole can hold material efficiently, confirmed by the presence of accretion disks.
Outer edgeRefers to the closest matter before entering the black hole.
Inner radiusThe radius becomes short as the black hole begins to spin.

Now, the accretion material has the potential to release its own energy, which actually serves as a feeding process.

It is mainly driven by forces, such as:

  • Friction
  • Gravity
  • Magnetohydrodynamic

A vast range of material is gathered and held and it must be efficient because there are accretion disks of one sort or another throughout the universe. 

The process continues and gives rise to supermassive black holes

The capture of Nearby Matter and Gas

the capture of nearby matter and gas

In the vastness of space accretion disks are pretty ubiquitous and orbit a wide variety of bodies, including neutron stars and entire galaxies.

Their range suggests they share a common law of physics, which they do, the law of angular momentum which states that angular momentum is always conserved.

It is the effect that forces matter and gas out of the disk and into a spiral streaming ever faster inwards until it passes out of sight over the event horizon.

On the way, the particles and gases in the rapidly moving stream of matter crash, collide, and churn raising temperatures and releasing observable X-rays.

These astronomers look for and use to find the black hole.

Fact: The exact effects of capturing nearby matter depends on how dense the black hole is, or how much of its mass is concentrated at one area and amplifies the effect of its gravity. 

Galactic Collisions and Mergers

galactic collisions and mergers

Supermassive black holes are capable of forces far greater than those of stella-mass black holes that can pull planets out of their orbits.

As they feast on the gases, they grow and merge producing forces so powerful they draw in galaxies like they’re pulling toffee. 

The Concept of Celestial Bodies Colliding with Each Other

celestial bodies colliding concept

Celestial bodies are set on collision courses that will eventually end with their dust blasting out radiation brighter than any star.

These collisions are thought to form a galactic supply chain, a delivery service that supplies the gases that feed the black hole and fuel its energy output.

Scientists have even evidenced the link between violent activity in a neighboring galaxy and increased black hole activity.

Fact: It is unclear if consuming the remains of galaxies can keep a supermassive black hole formed in the seconds after the Big Bang fueled 13.7 billion years later.   

The Role of Gravitational Forces and Interaction of Galaxies

gravitational forces and galaxy interaction

The gravitational forces of supermassive black holes push and pull at galaxies, which are typically disc shaped with a bulging middle.

When scientists measured bulges they discovered the measurements were closely related to the mass of the nearby black hole.

So close that in all likelihood the bodies formed and grew together in a co-evolution although how exactly remains a mystery. 

The Possible Explanation of the Process

Perhaps, as the galaxy’s gas fed into the black hole, it gave the occasional cosmic burp as a stream of energy and gas with all the elements needed to create a new star.

If it did, the mechanism used is unknown but it begs the question which came first, the galaxy or the black hole.

Fact: The supermassive black holes have been found in early-stage galaxies but there are galaxies that appear to have no black hole at their center which just adds to their enigma.  

Role of Dark Matter in the Formation of Supermassive Black Holes

Some of the black holes encountered are particularly active. Our own is almost dormant and barely feeding as are many others around us throughout the Milky Way.

dark matter and supermassive black hole formation

Some suggest it could be something to do with dark matter, a mysterious invisible component of the universe noticed by gravitational attraction.

It is theoretically accounted for in our present understanding of how the universe is expanding.

Still, there is also a theory that dark matter and black holes are part of the same kind of phenomena. 

Fact: Dark matter makes up about 68% of energy in the universe and around 27% of matter. 


How are supermassive black holes formed? Well, there are different theories, but nothing can be said for sure.

We know they had an important role in the formation of the universe and possibly have a role in its renewal and expansion.

We also know there could be billions of them, each blowing out gases and distributing the windblown atoms throughout the galaxy.  

But, there is plenty about supermassive black holes left to understand.