When a black hole is active, we tend to focus on the effect it has on the material it tilts. It makes sense to do it; the black holes themselves are difficult to probe. But the interaction between the black hole and the material should also have an effect on the black hole – as it gains material, it should also gain mass.
Such small feedback responses – especially those previously ignored as trivial – are known as side effects, and scientists have just observed an analog with one specific to black holes and which can be seen in water swirling in a canal. drain.
It is a detection that could help study the phenomena of black holes that are too subtle for our current instruments, such as Hawking radiation that is believed to be emitted by black holes. This is a theoretical type of black body radiation that would eventually – after a very, very long time – see a black hole completely evaporate, provided it did not grow at all.
In order to study cosmic objects in finer detail than we can over long distances in space, reduced or similar versions can be created in a laboratory. For example, a recent experiment to reproduce the pressures of the white dwarf core.
Black hole analogs are a great way to learn more about these enigmatic objects, and different types can help reveal their secrets in many ways.
Bose-Einstein fiber optics and condensates were used to learn more about Hawking radiation. But one of the simplest has to do with how black holes are fed: the vortex of the drain.
The accretion of the black hole can be compared to the water that spins on a drain. By treating matter like a wave in a field, water can withstand space-time itself or a field that ripples with quantum activity.
Measuring wave responses as water disappears on a spinning drain can have something to say about the energy waves that disappear into a black hole.
A vortex tub with analog black hole. (University of Nottingham)
From such analogies, I learned a lot about the effect of black holes on the space and material around them. But with an external water pump that keeps the background of the system constant, it was unclear whether an analogue with a black water hole would have the freedom to react to waves.
This set of experiments is the first time that a vortex of a bathtub has demonstrated an effect on the black hole itself.
“We have shown that analog black holes, like their gravitational counterparts, are intrinsic reaction systems,” said physicist Sam Patrick of the University of Nottingham in the United Kingdom.
“We have shown that waves moving in a drain tub push water down the plug hole, significantly altering the flow velocity and therefore changing the actual gravitational attraction of the analog black hole.”
When the waves were sent into the system in the direction of runoff, they pushed additional water, accelerating the process of “accumulation” so significantly that the water levels in the tub dropped considerably, even while a pump maintained the same level of water that it was penetrating.
This change in water level corresponds to a change in the properties of the black hole, the researchers said.
This could be extremely useful information, in part because an increase in mass changes the gravitational resistance of a black hole – it changes the way the black hole deforms its surrounding space-time, as well as the effect of the black hole on the accumulation disk. In addition, it offers a new way to study how waves can affect the dynamics of black holes.
“What was really striking to us was that the backlash is big enough to cause the whole water system to drop so high that you can see it with your own eyes! It was really unexpected,” Patrick said.
“Our study paves the way for experimental probing of the interactions between where and the space through which it moves. For example, this type of interaction will be crucial for investigating the evaporation of the black hole in the laboratory.”
The team ‘s research was published in Physical review letters.