On 1 September 1859, astronomer Richard Carrington watched an intensely bright flare erupt from a sunspot group. About 17.6 hours later — far faster than a typical coronal mass ejection (CME) — a wall of solar plasma slammed into Earth's magnetic field. The resulting geomagnetic storm produced aurorae visible near the equator, as far south as the Caribbean, and induced currents strong enough to spark fires in telegraph offices and let some operators send messages with their batteries disconnected.
A storm of Carrington's magnitude striking today's electrified world could damage extra-high-voltage transformers, disrupt satellites and GPS, and — according to some insurance-industry estimates — cost trillions of dollars in the worst-case scenarios.
Launch a coronal mass ejection from the Sun and watch it cross the gap to Earth, compress the dayside magnetosphere, push the aurora down toward the equator, and spark induced currents on a ground-level telegraph line — the same physics that set real telegraph offices alight in September 1859.
Faster ejecta compress Earth's dipole field lines on the sunward side and stretch the night-side tail, while geomagnetic activity (approximated here as a Kp-like index) expands the auroral oval toward lower latitudes and drives stronger geomagnetically induced currents.
Set the CME speed, then click Launch CME and watch it travel from the Sun to Earth. Toggle the magnetic field lines and telegraph sparks, or switch to Ground view to see the induced-current spark up close.
The 1859 storm's CME reportedly crossed the roughly 150-million-km Sun-Earth gap in about 17.6 hours — several times faster than a typical CME, which is why it hit with so little warning.