The Sunspot Number, the longest scientific experiment still ongoing, is a crucial tool used to study the solar dynamo, space weather and climate change. It has now been recalibrated and shows a consistent history of solar activity over the past few centuries. The new record has no significant long-term upward trend in solar activity since 1700, as was previously indicated. This suggests that rising global temperatures since the industrial revolution cannot be attributed to increased solar activity.
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| A drawing of the Sun made by Galileo Galilei on 23 June 1613 showing the positions and sizes of a number of sunspots. Galileo was one of the first to observe and document sunspots |
