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Sunspot activity has been measured using the Wolf number for about 300 years. This index (also known as the Zürich number) uses both the number of sunspots and the number of sunspot groups to compensate for measurement variations. A 2003 study found that sunspots had been more frequent since the 1940s than in the previous 1150 years. [30]
CMEs often form around sunspots, although scientists aren’t entirely sure why. Sunspot formation is cyclical, and the current solar cycle has reached the highest number of sunspots since 2001 ...
Schwabe continued to observe the sunspot cycle for another 23 years, until 1867. In 1852, Rudolf Wolf designated the first numbered solar cycle to have started in February 1755 based on Schwabe's and other observations. [6] Wolf also created a standard sunspot number index, the Wolf number, which continues to be used today.
Sunspot number is correlated with the intensity of solar radiation over the period since 1979, when satellite measurements became available. The variation caused by the sunspot cycle to solar output is on the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W·m −2 compared with 1366 W·m −2 for the average solar constant).
Moderately damaging earthquakes strike between New York and Wilmington, Delaware, about twice a century, the USGS said, and smaller earthquakes are felt in the region roughly every two to three years.
Earthquake lights may be classified into two different groups based on their time of appearance: (1) preseismic earthquake light, which generally occur a few seconds to up to a few weeks prior to an earthquake, and are generally observed closer to the epicenter and (2) coseismic earthquake light, which can occur either near the epicenter ...
About 55 earthquakes a day – 20,000 a year – are recorded by the National Earthquake Information Center. A quick guide to how they are measured. Earthquakes happen all the time, you just can't ...
The solar storms of May 2024 (also known as 2024 Mother's Day solar storm [1] or Gannon storm in memory of Jennifer Gannon, [2] a space weather physicist [3]) were a series of powerful solar storms with extreme solar flares and geomagnetic storm components that occurred from 10–13 May 2024 during solar cycle 25.