# Dangerous black holes may be hiding in the universe!

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The universe hides many secrets, including those related to black holes, which are regions of infinite density, known as singularities. But what if some of the holes are bare – completely lacking the boundaries of the horizon?

Singularities always come wrapped in event horizons, but a more detailed look at the mathematics of general relativity suggests that this may not necessarily be the case.

And if these naked black holes are spreading throughout the universe, new research reveals how we can discover one of them: by looking at the ring of light surrounding it.

Mathematical equations tell us that if a mass of matter collapses on itself to a very small volume, then the gravity of that substance will still shrink until it is refracted to a very small point. This point is called the singularity, and it’s an indication that the mathematics we use to describe spacetime collapses completely.

The attraction of singularities is infinitely strong, and objects can be pulled toward singularities faster than the speed of light. Near the singularities, the physics of general relativity can no longer predict the future path of the particles – one of the key points of physics.

And fortunately, as far as we know, all singularities are wrapped into the event horizon, which is the distance from the singularity where gravity is strong enough to pull anything – the point at which it must travel faster than the speed of light to escape. This is what makes a black hole black – not even light can escape from it.

Since we first discovered the existence of black holes, we have wondered whether it is possible to form a singularity without an associated event horizon – the so-called “naked” singularity. And this would be a really, really dangerous place, where the laws of physics would break down.

And if nude singularities are present, then it is definitely not uncommon. We know only one surefire way to forge singularities, and that’s when a giant star runs out of fuel and collapses in on itself. And when that happens, the Singularity naturally gets to the event horizon.

The existence of the nude singularity is so disturbing to physicists that they speculated that nature might not allow it to exist at all – but so far we have no evidence for this idea.

It may be possible to form naked singles, though only under the most extreme circumstances. If the black hole is spinning, it can form a second event horizon that lies inside the first. The faster the black hole rotates, the closer its event horizons are to each other. And if they spin fast enough, mathematics predicts that event horizons can be “canceled out” and reveal clear singularities.

So far, we haven’t recognized any black holes spinning fast enough to expose their singularities, but other than that, we usually don’t have a way to determine whether a random astrophysical object is an ordinary black hole or a naked singularity.

A theoretical physicist took this challenge head on by studying whether a nude singularity could reveal itself in other ways, especially if surrounded by a ring of material, as reported in a research paper published on November 12 on the arXiv server. This ring, called the accretion disc, is a common feature around black holes (and potentially bare singularities).

And when gas and dust fall on a dense and compact object, this substance flattens into a disk before it flows all the way. And this disc can be incredibly bright.

Most theoretical studies of abstract singularities have assumed that an object exists in isolation, which is not true in the real universe. In the new work, it was found that the accretion disk is not completely separate from the black hole (or the nude singularity). The disk itself has its own gravitational force, and can deform and deform the compact object in the center. This distortion, in turn, affects the gravitational environment around an object, subtly altering the path of matter rotating inward.

And it turns out that nude singularities behave a little differently than a regular black hole – the accretion disk around the nude singularity can be much brighter around a black hole. So far, our telescopes do not have sensitivity to tell the difference, and future devices, perhaps an updated version of the Event Horizon Telescope, could do the trick.

And more detailed studies of the environment around the confirmed naked singularity will reveal some of the universe’s most profound mysteries, according to “Life Science”.