Why does the direction of Bz matter?
Bt is the total magnetic-field strength. A sustained negative Bz points south and can help solar-wind energy enter Earth’s magnetic environment; it does not guarantee aurora.
Solar wind
Solar wind is a stream of particles from the Sun. Speed alone is not enough: the magnetic field it carries also matters for aurora.
Solar Wind Speed
400.40 km/sObservedProton Density
4.24 p/cm³ObservedBt:
8.49 nTObservedBz:
0.99 nTObservedGeomagnetic activity · Kp
3.00 KpObservedDst index
-34.00 nTObservedSolar Wind Speed
400.4 km/s
Interplanetary Magnetic Fields
8.49 nT
BtBz
Bt is the total magnetic-field strength. A sustained negative Bz points south and can help solar-wind energy enter Earth’s magnetic environment; it does not guarantee aurora.
Proton Density
4.24 p/cm³
Solar Wind Temperature
166,792 K
Has the measured solar wind already reached Earth?
Upstream spacecraft measure the wind before it arrives. Travel time depends on speed; the Earth reference is an estimate, not a fixed countdown.
Public scientific observations and forecasts may be delayed or revised. Forecasts are not guarantees of aurora visibility or operational safety. Follow official advice for critical decisions.