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25th of September 2020
Solar Cycle 25 starts
Solar Cycle 25 has started! Earlier this month, the official Solar Cycle 25 Prediction Panel, announced that solar minimum occurred in December 2019. The sun has an cycle of around 11 years, starting with a minimum in solar activity, and reaching a maximum about half-way through the cycle. As the Sun is quite variable, it takes some time to determine when the minimum has been reached. The solar cycle is tracked by monitoring sunspots -- the dark blotches on the Sun that are associated with solar activity. Solar cycle 1 was the first solar cycle since detailed recording of solar sunspot activity began, with solar cycle 1 beginning in February 1755. The solar cycle dictates what we can expect in terms of space weather: outbursts from the Sun can result in a range of effects, from aurorae to satellite orbital decay, and disruptions to radio communications or the power grid. The visible light images above are from NASA's Solar Dynamics Observatory and show the Sun at solar minimum in December 2019 and the last solar maximum in April 2014. Sunspots are visible on the Sun during solar maximum. (Image credits: NASA's Solar Dynamics Observatory/Joy Ng)

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