Perpetual darkness and frigid temperatures don’t usually pack in the tourists. But when you throw in some shimmering curtains of light in the sky, they show up in bunches.

In the last decade or so, the aurora borealis — the northern lights — has become big business. Tourists flock to Scandinavia, Iceland, Alaska, and similar sites to see it.

The aurora is formed by the interplay between Earth’s magnetic field and the solar wind — a flow of charged particles from the Sun. The magnetic field funnels the particles into the upper atmosphere, where they zap atoms and molecules, causing them to glow.

The aurora forms in a narrow ring around the magnetic north pole. Most of the time, the ring stays far north. So the aurora is best viewed from far-northern latitudes — places where the sky stays dark for weeks at a time.

Tourist bureaus, lodges, and others are playing up the aurora. They offer package deals that include sleigh rides, dog sledding, snowmobiling, and other activities. Resorts have built glass-domed igloos so visitors can stay cozy while they watch. Train operators offer glass-topped coaches, and ship lines are flogging aurora cruises.

You don’t need a package deal to see the aurora, though. You can visit a national park or other dark-sky site within the auroral zone. And several web sites post predictions of auroral activity — letting you know when and where to view these amazing light shows.

More about astronomy tourism tomorrow.

Script by Damond Benningfield