Can I see the aurora tonight?

The Sun is a star, a ball of hot gas held together by its own gravity and lit by fusion in its core. It never stops blowing charged gas out into space, the solar wind. Earth has a shield against it: its magnetic field, a vast bubble we live inside.

Some of the energy in the wind still gets in. It speeds up electrons, and Earth's magnetic field steers them down towards the polar regions. There they crash into oxygen and nitrogen high in the air. The gas lights up, much as a neon lamp does. That glow is the aurora: the northern lights in the north, the southern lights in the south.

It shines between between 80 and 500 kilometres up. Oxygen gives green, and red higher up. Nitrogen adds blue and pink. Right now NOAA's model puts the power flowing into the northern aurora at 39 billion watts.

It must be dark. The aurora may be there by day, but only the night shows it. That rules out the white summer nights in the far north. Get away from city lights. A full Moon makes the aurora look fainter too.

The best hours are usually within an hour or two of midnight, NOAA says, between about 10 pm and 2 am local time. When the storm is strong, the active hours spread into the evening and the early morning. Look towards the pole: north in the northern half of the world, south in the southern half.

A camera helps. Phone and camera sensors are sensitive enough to record aurora too faint for our eyes. Far from the pole, the lights often show first as a red glow, because the oxygen that glows red sits highest in the air and can be seen from farthest away.

On 10 May 2024 NOAA observed an extreme geomagnetic storm, the first since October 2003. Kp reached 9, the top of the scale. Aurora were seen far from the poles.

Five months later, on 10 and 11 October 2024, a cloud from an X-class flare struck and NOAA observed a severe storm, one level below extreme. The aurora reached far from the poles again.

Both came near the peak of Solar Cycle 25, when the Sun throws out the most eruptions. Sunspots have grown fewer since then: the latest monthly sunspot number is about 60. The last storm of any size ended 9.1 days ago.