CME Tracker
Coronal Mass Ejection Monitoring
NASA DONKI-powered CME detection with WSA-ENLIL modeled arrival times and geomagnetic impact forecasts.
Active CMEs (3d)
Earth-Directed
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Next Arrival
Heliospheric CME propagation · Live overlay available
Live aurora data →Recent CME events
NASA DONKI · Last 3 daysHow long does a CME take to reach Earth?
A coronal mass ejection is a burst of solar plasma and magnetic field hurled from the Sun's corona. Travel time to Earth depends almost entirely on speed: a fast, powerful CME can cross the roughly 150 million km gap in as little as 15 to 18 hours, while a slower, more typical eruption can take 2 to 4 days. Not every CME is Earth-directed — many erupt away from our planet entirely and never arrive at all.
Once a CME's magnetic field connects with Earth's, it can compress the magnetosphere and drive geomagnetic storms — the same activity that fuels bright aurora. That's why the "Next Arrival" estimate above is one of the most useful numbers on this page: it's an early warning for when to start watching the aurora forecast closely.