Researchers have developed an innovative engine using a tiny glass sphere that demonstrates remarkable behaviors at extreme temperatures. This sphere, measuring just 5 micrometers in diameter, is suspended in a near-vacuum through an electric field. A study published in Physical Review Letters explains how this unique setup allows the sphere to mimic temperatures reaching an astonishing 13 million Celsius, nearly matching the core temperature of the sun.
Despite these extreme conditions, the glass sphere remains cool to the touch. This phenomenon occurs because its effective temperature derives from the energy associated with the sphere’s overall motion, rather than the energy of individual molecules, which typically determines temperature. As physicist James Millen from King’s College London notes, “It is moving as if you had put this object into a gas that was that hot. It moves around like crazy.”
Implications for Thermodynamics and Biological Research
The findings also shed light on the peculiarities of thermodynamics at the microscale. According to John Bechhoefer, a physicist at Simon Fraser University, achieving effective temperatures this high is particularly impressive for such a small object. He emphasizes that larger engines could potentially reach even greater effective temperatures.
In thermodynamic terms, the glass sphere functions as a heat engine, a system that converts heat from a high-temperature source into mechanical work while transferring waste heat to a cooler area. The sphere’s hot-to-cold temperature ratio is approximately 100, significantly higher than the typical ratio of around 3 seen in conventional engines. This high ratio is critical as it suggests improved efficiency and performance.
The researchers observed that the engine’s performance varied widely, with efficiencies fluctuating between 10 percent and an astonishing 200 percent. In some instances, the engine even operated in reverse, cooling down instead of heating up. Millen describes the unpredictability of thermodynamics at this scale as “really, really weird,” comparing its complexity to that of quantum mechanics.
Potential Applications in Biological Sciences
This groundbreaking research may have significant implications for understanding biological processes. The behavior of the glass sphere can help scientists investigate microscopic engines, such as kinesin, a motor protein responsible for transporting cargo within cells. These insights are vital for grasping how tiny structures, like proteins, are influenced by their environment.
While the glass sphere itself may not serve a practical function in the traditional sense, Millen describes it as a “perfect analog of an engine” for researchers to manipulate and study the operational dynamics of such small devices. By observing how the sphere responds to the electric field, scientists can explore phenomena like position-dependent diffusion, which plays a crucial role in biological activities, including protein folding.
The research represents a unique convergence of three fascinating attributes: extreme temperature, a substantial hot-to-cold ratio, and position-dependent diffusion. Uroš Delić from TU Wien highlights the significance of combining these elements, remarking that this work is “quite cool — or hot.”
As scientists continue to explore the intricate world of microscale thermodynamics, this tiny glass sphere could pave the way for innovative advancements in both physics and biology.
