Dumb Holes: Smarter Than You (Think)


By Ethan Xie

Black holes are interesting creatures, but they also happen to be the most violent and angry looking dots that we have ever come across. As a result, it’s really, really ethically questionable to research them. Anyone who gets close just doesn’t come back. That and they are thousands of lightyears away and normally lie in the center of galaxies.

Unfortunately, black holes also happen to be the most important phenomenon when it comes to explaining how the universe will all end. We know that they radiate away due to Hawking radiation, but finding what is left over results in numerous paradoxes involving the loss of information and/or the universe being a hologram (holographic principle).

Since black holes are so crucial, yet inaccessible, scientists have looked for human-made ways to create and simulate their effects in a lab. But, when you program software to simulate something that may as well have infinite gravity, the physics completely breaks down, and therefore so does your code, crashing your computer. That is where dumb holes, also known as sonic or acoustic black holes, come in. These objects are still angry dots, but they only have enough gravitational energy to suck in all sound, not light. This strange property makes them extreme enough to be used as a model, but also normal enough to be created. It’s this property that gives them their characteristically “dumb” nature.

That’s not to say dumb hole still aren’t one of the craziest things that humankind has invented. On the contrary, their creation is incredibly technical and requires pinpoint precision to allow not even a single sound wave escape from their acoustic horizon. In order to achieve such perfection, scientists rely on the symmetry of fluids in nature when they form a sphere. This is because fluids are based around equations which are almost identical to the radiation in a gravitational field. Specifically, the sphere created by Bose-Einstein Condensate fluids flowing faster than the speed of sound will be perfectly uniform and leave no holes for waves to escape. This creation process does have downsides, however. Firstly, dumb holes are very, very small because the energy and mass required to create them increase exponentially as their size increases. In addition, dumb holes have a limited lifespan, as they undergo a process similar to hawking radiation and slowly die out in the lab.

So why do we care? Well, as mentioned before, these serve as simulations for what actually occurs in nature. Scientists are hoping that by studying dumb holes, they will find evidence to further the claims and theories made by modern phycisists. This evidence usually comes in the form of particle emissions, which are given off by the black hole at the event horizon, much like the predicted particles given off by hawking radiation. While it may seem unintuitive for stuff to fly outside a black hole instead of in, there is a very interesting explanation as to why this phenomenon occurs. To put it simply, our universe is in a permanent state of dynamic equilibrium, in which matter and antimatter (photons) are being instantaneously created and destroyed by each other. This does not apply to the edge of a black hole, however. At this very surface, one particle gets sucked in while the other flies out into space, leading to an imbalance in nature. This imbalance is emitted as hawking radiation. Dumb holes undergo a similar process but with phonons (sound particles) instead of photons. This is a life-saver for physicists because Hawking radiation is an incredibly slow process that we will never be able to witness to a measurable degree. Dumb holes are our next best option, and so far their results have confirmed both Steven Hawking’s theories and modern physicist ideas.

Aside from Hawking Radiation, dumb holes have many other important uses as well. One of these uses is finding the physical properties of a black hole. Since you obviously can’t stick a thermometer into a angry black dot, it is much more effective to measure the temperature of a dumb hole instead. By taking measurements such as this, we can plug them into our current equations and theories to verify. And so far, our equations have luckily been supported. This culminates in a strong general understanding of gravity at the quantum level because, while we don’t fully understand those interactions, we do have stable theories for the corresponding fluids in dumb holes.

They’re still really stupid in my book though.

Works cited:How Scientists Are Making ‘Sonic’ Black Holes in a Lab