The Tonga volcano that erupted in January set a record. It was the biggest explosion ever recorded using modern technology. It was also the biggest in the past 150 years. Scientists say it may have been as big as the 1883 Krakatoa eruption. A researcher said: "Tonga was a truly global event....But we've now got all these geo-physical [recording] systems, and they recorded something that was really [unmatched] in the modern data."

The eruption sent shock waves and tsunami waves around the world. People heard sonic booms in Alaska. It even made clouds in the UK disappear. The UK is 16,500km from Tonga. A UK scientist said the atmosphere was very interconnected. He said: "What happens on one side of the planet can [spread] around to the other side at the speed of sound." NASA said the volcano's effects reached space and affected the weather in space.