Researchers have developed a technique for steering microscopic swimming robots utilizing mild patterns and the rules of Einstein’s concept of relativity. The expertise is a possible first step towards deploying tiny robots in functions starting from drugs to manufacturing.
One of the key challenges of growing microrobots for sensible functions is creating ones able to navigation with out the inclusion of cumbersome sensors and different electronics, which might make the machines too massive to function on the desired scale (like inside a human physique). In an try to beat this subject, physicists on the University of Pennsylvania created “artificial space-time” to direct machines to journey in the identical method that spacecraft or mild does whereas crossing the universe.
The problem was to information the microscopic machines with sufficient precision for them to succeed in a particular level in area, with out being stymied by the maze’s partitions. That’s the place relativity got here in. According to Einstein’s concept of normal relativity, gravity bends space-time around objects with mass. Light and objects follow “straight” geodesics — the shortest paths — that look bent around masses. A great example of this is gravitational lensing: Although light travels in a straight line across the cosmos, it can appear bent and magnified when passing through the gravitational well of a massive object, such as a large galaxy cluster.
“We showed that the way EK robots behave in patterned light fields is identical to the paths light follows in general relativity,” lead study author Marc Miskin, an assistant professor {of electrical} and techniques engineering on the University of Pennsylvania, informed Live Science in an e mail. “Amazingly, you can use the robots as a gravity analog since the correspondence is exact. Alternatively, you can turn general relativity ideas around to use them to guide robots: in the same way gravity pulls objects together, you can guide robots to a specific spot.”
Artificial space-time
To mimic the impact, the crew modeled the maze as curved digital area utilizing relativity equations. Paths to the goal contained in the maze turned easy straight strains within the mannequin. Then, they transformed the mannequin again to a 2D mild map. Dark spots naturally attracted the bots, whereas brighter spots repelled them. The finish level of the maze was the darkest spot (a type of fake black hole), with obstacles being more brightly lit.
Regardless of where they were initially placed, the EK bots naturally followed these geodesics, dodging walls automatically, as if sliding downhill in warped space. The team published their findings in November 2025 in the journal npj Robotics.
For Miskin, the study is a bridge between the worlds of physics and technology, “rather than a competition between them,” he said. “On the one hand, relativity and light are very well understood; connecting reactive control to them invites new ways of thinking and established tools for robotics. On the other hand, general relativity and optics are also very abstract (think bending spacetime), while robotics is mechanistic and concrete (it’s very easy to understand why the robot does what it does). In addition to showing how new types of robots behave according to known theories of optics, the experiments give researchers “a bit more” insight into general relativity, particularly in exploring the impact of “flat space-times” in 2D spaces, Miskin added.
While the maze study is a very early step, Miskin said practical applications may emerge over the next 10 years.
“Some use cases we’re interested in exploring include checking up on teeth following a root canal, a kind of dental biopsy to make sure everything was cleared, eliminating tumors after making local measurements to confirm cells are cancerous, or even, outside of bio, assembly of microchips with tiny robotic helpers,” Miskin said. “The microworld is a fascinating place; I wouldn’t be surprised if these ideas are just the tip of the iceberg.”