Black holes are among the most fascinating and hotly debated objects in the universe.
They have captured the public’s imagination for decades, thanks in part to the late Stephen Hawking, who transformed them from a hard-to-understand scientific theory to a source of mysterious wonder.
They’ve also seeped into popular culture through science fiction magazines, Star Trek, and Hollywood blockbusters.
But what are the five most bizarre and captivating theories about black holes that are so inscrutable that they blow your mind?
MailOnline takes a look here.
Mysterious: Black holes are among the most fascinating and hotly debated objects in the universe (stock image)
1. They are surrounded by a ‘ring of fire’
In 2019, astronomers took the first-ever picture of a black hole in a distant galaxy.
Described by scientists as “a monster,” it is three million times the size of Earth.
The image shows an intensely bright “ring of fire,” as researchers described it, surrounding a perfectly circular dark hole.
‘It feels like you’re looking at the gates of hell,’ says Heino Falcke of Radboud University in Nijmegen.
As black holes consume matter that strays too close, they compress it into a superheated disc of glowing gas.
In the image of the giant black hole at the heart of the nearby galaxy Messier 87 (M87), the bottom of the ring appears bright as the gases there are flung toward Earth.
The black hole also bends light around it, creating the circular shadow.
In a historic first, scientists have captured a remarkable image of a supermassive black hole at the heart of our galaxy
2. They have ‘hair’
In 2015, the late physicist professor Stephen Hawking suggested that black holes were not the “eternal prisons” many think they are, adding that it was possible that data could escape the abyss.
A year later, he expanded on the theory by stating that the answer lies in the zero-energy particles, or “soft hairs,” that sit on the black hole’s horizon.
In 2015, Professor Stephen Hawking suggested that black holes were not the “eternal prisons” many believe them to be, adding that it was possible that data could escape the abyss. A year later, he expanded on the theory by stating that the answer lies in the zero-energy particles, or “soft hairs,” that sit on the black hole’s horizon (stock image)
It suggests that particles sitting on the event horizon, the black hole’s boundary, would be made up of photons and gravitons, which are subatomic packages of light and gravity.
These very low or even zero-energy quantum particles deposited on the edge of the black hole can capture and store information stripped from the particles falling into the black hole.
This basically means that while the particles falling into the black hole may be gone, their information lingers on the verge of oblivion in this “soft hair” of quantum particles.
The theoretical physicist likened the return of information to a burned encyclopedia, where information technically wouldn’t be lost but would be incredibly difficult to decipher.
The hypothesis has not been proven, but could help solve a long-standing paradox about what happens to gas and dust that has fallen into a black hole.
3. They emit gas fountains
A black hole’s powerful gravitational hold means nothing can escape if it gets extremely close to the edge of the hole.
But many of these mysterious objects are actually surrounded by a buildup of gas and dust that orbit black holes, a bit like water flowing down a drain.
According to a 2018 study, this build-up of material is a three-step process.
A black hole’s powerful gravitational hold means nothing can escape if it gets extremely close to the edge of the hole. But many of these mysterious objects are surrounded by a buildup of gas and dust that shoots straight into the sky and closely resembles fountains.
First, the cold gas forms a disk near the plane of rotation, which heats up until the molecules break apart.
Some of these molecules are ejected above and below the disc, which then fall back down to create a fountain-like structure.
Alternate observations also suggest that this motion produces arcuate rings surrounding the inner columns of matter, which shoot straight into the sky and closely resemble fountains.
4. They are the source of dark energy
Last month, scientists at Imperial College London made an exciting announcement about black holes.
They excitingly revealed that the objects may be the source of unknown energy known as dark energy.
Essentially, the big bang theory of our universe’s creation originally predicted that its expansion would slow down — or even begin to contract — because of the pull of gravity.
Breakthrough: Scientists have found the first evidence that black holes are the source of dark energy. They studied galaxies and the supermassive black holes at their hearts. Pictured is NGC 1316, a lenticular galaxy about 60 million light-years away in the constellation Fornax
But in 1998, astronomers were surprised to discover that not only was the universe still expanding, but that the expansion was accelerating.
To explain this discovery, it was proposed that a “dark energy” was responsible for pushing things apart more strongly than gravity.
This was linked to a concept Einstein had proposed but later rejected – a “cosmological constant” that counteracted gravity and kept the universe from collapsing.
However, black holes posed a problem – their extremely strong gravity is hard to resist, especially at their centers, where everything seems to fall apart in a phenomenon called “singularity.”
To go deeper into the problem, a team of 17 researchers from nine countries studied nine billion years of black hole evolution.
They observed old and dormant galaxies and found that black holes gain mass in a way that is consistent with them containing vacuum energy or dark energy.
In fact, the size of the universe closely matched the mass of supermassive black holes at the heart of galaxies at different times.
In other words, the amount of dark energy in the universe can be explained by black hole vacuum energy – meaning black holes are the source of dark energy.
5. They may be “back doors” to other parts of the universe
Deep inside a black hole is the gravitational singularity, where space-time bends to infinity and can survive whatever passes through it.
Or so has always been thought.
However, in a recent study, researchers suggested that there may be a way out through a wormhole at the center of the black hole, which acts as a “back door.”
Deep inside a black hole is the gravitational singularity, where space-time bends toward infinity and can survive whatever passes through it (stock image)
According to this theory, anything traveling through the black hole would “spaghetti,” or be stretched to its limits, but return to its normal size when it emerges in another part of the universe.
While it’s unlikely that a human would survive this process, the researchers say the matter in the black hole wouldn’t be lost forever, as previously thought, but would instead be expelled to another part of the universe.
And the researchers say no “exotic” energy would be needed to generate the wormhole, as Einstein’s theory of gravity suggests.
BLACK HOLES HAVE A GRAVITY SO STRONG THAT EVEN LIGHT CANNOT ESCAPE
Black holes are so dense and their gravitational pull is so strong that no form of radiation can escape them – not even light.
They act as intense sources of gravity that suck up dust and gas around them. Their intense gravity is believed to be what stars in galaxies revolve around.
How they are formed is still poorly understood. Astronomers believe they may form when a large cloud of gas up to 100,000 times larger than the sun collapses into a black hole.
Many of these black hole seeds then coalesce to form much larger supermassive black holes, which can be found at the center of every known massive galaxy.
Alternatively, a supermassive black hole seed could come from a giant star, about 100 times the mass of the sun, eventually forming into a black hole after running out of fuel and collapsing.
When these giant stars die, they also go “supernova,” a massive explosion that expels the matter from the star’s outer layers into deep space.