Space

A century of storms hitting Earth

The Sun's spots are one thing; the disturbance they throw at us is another. This is the needle. The planetary Kp index has logged Earth's geomagnetic weather every three hours since 1932 — a quasi-log 0–9 pulse read from magnetometers under the aurora. Play a century of it and the needle barely stirs in quiet years, breathes with the eleven-year solar cycle, and slams to the pin in the great storms — the same swing that once collapsed a power grid. Tap or hover the timeline to travel to any day.

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Jump to the great storms

Data & source

Source: the planetary Kp / ap index from GFZ Helmholtz Centre Potsdam · CC BY 4.0 · fetched —. Kp is a quasi-logarithmic 0–9 index of geomagnetic disturbance derived from 13 subauroral magnetometers, published every three hours since 1 January 1932; here each day is its strongest three-hour Kp. The needle and aurora are a stylized instrument — deflection and the green glow are driven by that day's peak Kp and exaggerated to be visible, not a literal compass reading or a forecast of where aurora was seen. Storm level is the NOAA G-scale (G1 = Kp 5 … G5 = Kp 9). The named storms below are documented events; their Kp is read from this file.