Sunlight-Powered Tiny Discs Achieve Levitation in Upper Atmosphere

Swift Summary

• Scientists have developed fingernail-size discs that levitate using sunlight and harness the phenomenon of photophoresis,first described 150 years ago.
• These discs could explore Earth’s mesosphere,a region challenging to study,providing insights into weather and climate patterns.
• The devices are constructed with aluminium oxide sheets containing micro-scale holes; their design generates upward airflow under light exposure.
• Laboratory tests demonstrated levitation at air pressures much weaker than Earth’s surface atmosphere. Low-pressure conditions exist in the mesosphere (50-85 km above Earth).
• Scaling up to 3 cm in size could allow these discs to carry sensors for atmospheric monitoring at altitudes of 75 km.
• A start-up called Rarefied Technologies aims to commercialize these high-altitude devices for purposes such as telecommunications and scientific study.

Image Credit: Schafer et al., Nature – An illustration of solar-powered levitating discs.