Imagine an engine so small it’s made from a 5-micrometre glass bead, yet it can generate an effective temperature hotter than the sun’s core – around 13 million degrees Celsius! Scientists have recently achieved this marvel by suspending a tiny glass sphere in an electric field. While the bead itself remains cool, its internal energy, driven by violent vibrations, reaches this incredible “effective heat.” This fascinating setup offers a unique window into the peculiar world of thermodynamics at the microscopic level.
A Levitated Engine Mimicking Stellar Temperatures
The research involved trapping a minuscule 5-micrometre glass sphere within an electric field in a vacuum. By applying an oscillating voltage, scientists induced violent jitters in the sphere. This intense kinetic motion resulted in an “effective temperature” that soared to approximately 13 million degrees Celsius, remarkably similar to the scorching heart of the Sun. Despite this extreme simulation, the glass bead itself stayed close to room temperature. As explained by James Millen, a physicist and co-author from King’s College London, this “heat” is entirely kinetic—the sphere behaves as if it were immersed in a gas of that immense temperature.
Exploring Unpredictable Thermodynamics at the Nanoscale
Scientists are studying this levitated bead as a unique form of heat engine. What makes it truly remarkable is its hot-to-cold temperature ratio, which stands at an astonishing 100:1 – far greater than the typical 3:1 ratio seen in conventional engines. Its efficiency also displayed highly erratic behavior, at times exceeding 100% or even briefly operating in reverse. This unpredictability highlights the bizarre nature of thermodynamics at such tiny scales. These experiments are crucial for understanding how miniature natural “machines,” like the motor protein kinesin found in living cells, function under comparable turbulent conditions. While the levitated sphere isn’t designed for practical applications itself, it serves as an ideal model for scientists to delve deeper into the mysteries of microscopic heat engines.