Muons reveal upper atmosphere’s temperature

Published in Physics World, 23 Jan 2009

Scientists interested in the upper atmosphere should turn their attention to measurements made deep underground — says an international team of physicists who have noticed that the number of cosmic-ray remnants hitting Earth is linked to freak warming events in the upper atmosphere. The link implies that measurements of cosmic rays — both future and past — could help scientists improve climate and weather forecast models.

Cosmic rays are mostly high-energy protons and are constantly bombarding atoms in Earth’s atmosphere to create pions. These pions either decay into lighter muons or continue to interact with nearby atoms and avoid decaying into muons. If the atmosphere is cool and thick then the chance of continued interactions is much higher, and the number of muons generated is therefore far fewer than when the atmosphere is warmer. […]

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