Whistles, cracks, hisses: the noises of the northern lights

Study finds some strong auroras are accompanied by noises from changes in the atmosphere

You may have seen the shimmering greens and pinks of the aurora borealis lighting up the night sky, but have you ever heard them? Rare reports of crackling and whooshing noises accompanying auroras have traditionally been dismissed by scientists as folklore, but data gathered in Finland has shown that under the right weather conditions, auroras can be accompanied by a noise.

The northern (and southern) lights are caused by solar particles colliding with gas molecules in Earth's upper atmosphere. They tend to be visible near the poles because the charged particles are steered towards the poles by Earth's magnetic field. But most aurora take place well out of earshot, about 62 miles (100km) above our heads.