ARIES Team Finds Faster Rotation in Sun’s Upper Atmosphere — Implications for Space Weather

Overview The Ministry of Science & Technology announced a breakthrough study showing that the Sun’s outer atmosphere rotates significantly faster than its visible surface. The discovery challenges the classical notion of angular momentum conservation in a gaseous star and has direct relevance for modelling solar activity and space‑weather impacts on Earth. Key Developments Researchers from ARIES , Udaipur Solar Observatory, Physical Research Laboratory and Ahmednagar College used data from the Nobeyama Radioheliograph to measure rotation speeds at different heights. The rotation rate increases with altitude above the solar surface, contrary to expectations that the gaseous envelope would rotate uniformly. When solar activity rises (more sunspots ), the atmospheric rotation slows slightly, indicating a complex interaction between magnetic fields and plasma dynamics. Important Facts The team applied a 2D image‑correlation method to two radio images taken on separate days. By cropping the images to identical regions and measuring the shift, they derived the rotational velocity at various heights. The findings were published in Astronomy & Astrophysics Letters (2025). The study also notes a modest decrease in rotation speed during periods of high sunspot numbers. UPSC Relevance Understanding solar dynamics is vital for several GS papers. GS3 (Science & Technology) requires knowledge of space weather and its impact on satellite communication, navigation and power grids. GS1 (Governance) covers the role of ministries and research institutes like Ministry of Science & Technology in fostering such research. GS4 (Ethics) touches on responsible use of scientific knowledge to safeguard infrastructure. Way Forward Further observations across multiple wavelengths are needed to map the full three‑dimensional rotation profile. Integrating these results into solar‑activity models will improve forecasts of geomagnetic storms, helping agencies like ISRO and the Ministry of Earth Sciences to protect critical assets. Collaborative projects between Indian institutes and international observatories should be encouraged to deepen our grasp of stellar physics.