They Predicted the Weakest Solar Cycle in 200 Years... They Were Wrong

In December 2019, an international panel of solar physicists published one number: 115 sunspots at the peak of Solar Cycle 25, arriving July 2025. The real peak landed in October 2024 at 161, nine months early and forty percent above the forecast. This is the post-mortem — who made that call, who publicly disagreed and was ignored, and what the miss cost the people who planned around it.

You'll get the full paper trail: the co-chair's own account of how the room reached consensus so easily, the rival forecast from NCAR that doubled the official number, the 2011 press conference where three independent teams announced the sun might be shutting down, and the 2015 press release that turned a sunspot forecast into a "mini ice age" the underlying paper never mentioned. Then the bill: a G5 storm in May 2024, seventy metres of GPS drift across the American corn belt, and satellites burning up ten times faster than the models allowed for.

The video ends on the part almost nobody covers. Every polar precursor forecast ever made rests on the magnetic field strength at the sun's poles — and until March 2025, when Solar Orbiter tilted out of the ecliptic, nobody had ever directly seen them.

This video covers solar cycle forecasting, an area where competing methods still disagree. Predictions for Cycle 26 and the timing of severe space weather are open questions, not settled results.

═══ The Team ═══

Scriptwriters:
Tahimy K.
Thom H.

Voice-overs:
Matthew Sheppard: mattsheppardvo.com
Thom H.

Thumbnails:
Johayna A.
Tahimy K.

Editing:
Johayna A.
Tahimy K.

═══ SOURCES ═══

The panel, in its own words — "How Scientists Are Tackling the Tricky Task of Solar Cycle Prediction", Lisa Upton interviewed in Quanta Magazine, 2023
http://quantamagazine.org/how-scientists-are-tackling-the-tricky-task-of-solar-cycle-prediction-20230907

The forecast that doubled it and got ignored — McIntosh & Leamon, NCAR, Solar Physics, 2020
http://news.ucar.edu/132771/new-sunspot-cycle-could-be-one-strongest-record

What the sun actually did — Solar Cycle 25 maximum, October 2024, SIDC/SILSO, Royal Observatory of Belgium
http://sidc.be/article/solar-cycle-25-reached-its-maximum-october-2024

Why one sunspot group can hijack a cycle — "The Effect of 'Rogue' Active Regions on the Solar Cycle", Nagy, Lemerle, Labonville, Petrovay & Charbonneau, Solar Physics, 2017
arxiv.org/pdf/1712.02185

The first look at the poles — Sami Solanki, Max Planck Institute for Solar System Research / ESA Solar Orbiter, March 2025
esa.int/Science_Exploration/Space_Science/Solar_Orbiter/Solar_Orbiter_gets_world-first_views_of_the_Sun_s_poles

Images: NASA/SDO · ESA/Solar Orbiter/PHI · SIDC/SILSO
Animated diagrams illustrate the mechanisms described. They are not mission footage.

═══ CONTINUE THE DISCUSSION ═══

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