The problem with microrobots is that they don’t have a “brain.” The solution has been to use Einstein’s relativity to guide them

Making robots the size of a piece of human hair is already a reality, but it faces a big problem: they are too small to bring a “brain” on board. And it is logical, since on a microscopic scale there is no space to insert a microchip, batteries or navigation systems, so in a few words we can talk about “dumb robots” that only react to basic stimuli. But here the Einstein’s relativity has given a small solution.

The solution. One of the functions of these small robots is precisely in be able to navigate the bloodstream to react to different stimuli. But the big question here is how they can navigate a bloodstream without colliding with each other. Something that was on the mind of a team of researchers from the University of Pennsylvania what have you seen that the key is not in making robots smarter, but in manipulating the “spacetime” through which they move.

To understand this thread, you have to think about how gravity works according to the theory of general relativity. Here Einstein taught us that planets do not revolve around the sun because an invisible force pulls them, but because the mass of the Sun curves the fabric of spacetime, as with the Earth, which follows the easiest path through that curved space.

To biology. Here the researchers wanted to apply this same mathematical principle to microrobotics, introducing the concept of “artificial spacetimes”. And since microscopic robots move in response to light, the scientists designed light fields projected onto a Petri dish that mimic the curvature of spacetime. In this way, the variations in light they faced acted like “artificial gravity.”

In this way, the robot does not need to know where it is or where it is going. It simply turns on and moves forward, since it is the light pattern that “pushes” it to curve its path to avoid obstacles or find the exit from a maze, exactly like a ray of light curves when passing near a massive object in the cosmos.

It seems like magic. In the experiment proposed by the researchers, different two-dimensional light labyrinths are projected. In this virtual scenario, they created dark areas that mathematically act as “black holes”, since when the microrobot approaches these areas, the equations that govern your response to light They are formally identical to those of the path of light falling through an extreme gravitational field.

In this way, when the microrobot approaches these areas, the equations that govern its response to light are formally identical to those of the path of light falling through an extreme gravitational field. From here, using mapping, scientists managed to get these robots to ‘patrol’ specific areas, avoid obstacles and group together at an exact point.

And the most interesting thing is that all this happens without a single processing chip on board the robot, since the “calculation” falls entirely on the geometry of the projected environment.

A future doctor. The implications of this advance will now allow microrobots to be freed from the need to have a computer system inside them, which means they can be manufactured cheaply and even made even smaller. From here opens the door to very important medical applicationssince millions of these “reactive robots” can be injected into the human body.

The objective here is to use external fields such as magnetic fields that act as a curved spacetime that allows them to move through our circulatory system to release a drug, clean arteries or perform biopsies at the cellular level.

Images | Ruben Sukatendel

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