His geomagnetic surveys showed that auroral activity was nearly uninterrupted.

Magnetometers can give an indication of auroral activity before the light from the aurora becomes visible.

The Arctic tundra and boreal forest surrounding the town see over 300 nights of auroral activity each year.

He observed the variations of a compass needle and found that larger deflections correlated with stronger auroral activity.

If the planet has auroral activity, they said, it is presumably very faint.

One surprise, Dr. Spann said, is how auroral activity at night is sometimes mysteriously echoed on the day side.

It is also notable for the fact that it is the first time where the phenomena of auroral activity and electricity were unambiguously linked.

Our arrival is timed for 10.30pm: "magnetic midnight", when the local auroral activity should be at its most intense.

Eighty miles, close to maximum and right in the middle of the main altitude of auroral activity.

At this time of year the aurora borealis can occasionally be seen on the northern horizon during moderate auroral activity.