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
390.80 km/sObservedProton Density
3.56 p/cm³ObservedBt:
10.21 nTObservedBz:
-5.59 nTObservedGeomagnetic activity · Kp
3.00 KpDelayed dataDst index
-34.00 nTObservedSolar Wind Speed
390.8 km/s
Interplanetary Magnetic Fields
10.21 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
3.56 p/cm³
Solar Wind Temperature
143,564 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.