Strange upward lightning shoots out X-rays as it rises to the clouds

Lightning can shoot upwards from tall towers – and researchers now know that it produces X-rays at the very beginning of its ascent into the clouds.

During a thunderstorm, different parts of a cloud become positively and negatively charged. This separation of charge across the cloud leads to a dramatic electrical discharge that manifests as a column of hot ionised gas and electrons, or plasma, reaching for the ground: a lightning strike.

But when charged-up clouds hover over a tall structure made …