Astronauts Scott Kelly and Tim Peake captured the northern lights, also called aurora borealis, from the International Space Station in 2016. (NASA/NASA)

When Don Hampton was a graduate student in Alaska, he looked up at the night sky and saw candy-colored lights swirling above his head. Fireworks? No, nature’s laser show.

“The sky lit up with patterns of green and bright pink,” he said. “The motion and scale were just amazing.”

Hampton was experiencing the aurora borealis (pronounced uh-roar-uh boar-ee-alice), an astronomical phenomena that is typically visible in the Northern Hemisphere from September through March. He now sees the northern lights 30 to 40 times a year, one of the benefits of being a professor of geophysics at the University of Alaska Fairbanks.

“I never get tired of watching them,” he said.

Elizabeth MacDonald, a research scientist at NASA’s Goddard Space Flight Center in Maryland, also studies the northern lights for a living. The splashy display never fails to amaze her. “You just look up at the sky and say, ‘Wow,’ ” she said.

We asked the two experts to explain the science behind the aurora borealis and where you can see the lights in your parka — or your pajamas.

What causes the aurora borealis?

The sun releases energy in the form of light and particles — “a glitter bomb of charged particles,” MacDonald said — that travels 93 million miles to Earth. The particles collide with gases in the upper atmosphere and create ribbons of color that move like ghostly dancers on a dark stage. The most common color combination is neon green with pink edges, but the sky can resemble a paint box with shades of red, blue and violet.

Some places in Alaska, including the Poker Flat Research Range, are great spots to see the lights. (NASA/NASA)
Where does it happen?

The Earth’s magnetic field draws the sun’s particles toward the poles. Aurora borealis takes place near the northern polar regions, about 60 to 180 miles above planet’s surface. (Its twin, aurora australis, occurs during the Southern Hemisphere’s winter, from March through September.) For the biggest and brightest show, Earthlings should book a plane ticket to Fairbanks, Iceland, northern Scandinavia or Yellowknife, Canada.

The northern lights are seen near Fairbanks, Alaska. (Terry Zaperach/NASA)
What are the best conditions for seeing the lights? Do you need any special equipment?

The ideal setting is pitch-black with a clear, moonless sky. “You have to be able to see the stars,” MacDonald said. Winter is the best season for viewing. Summer is the worst because near the Arctic Circle the sun is out all night, or most of it. So the northern lights can’t be seen. The spectacle often peaks around midnight and can last from five minutes to several hours. For gear, you just need your eyes, but a digital camera can help, too. “Cameras have better night vision,” MacDonald said. “They pick up more color.” For a sharper image, Hampton recommends placing your camera on a tripod, railing or other steady surface.

If you live far from the lights, can you still see them?

Yes, you can. Several organizations set up video cameras to capture the northern lights and share the real-time images on their websites. Bundle up in your coziest pajamas and check out the Geophysical Institute , part of the University of Alaska Fairbanks; AuroraMax, which is run by the Canadian Space Agency; or Gnometech, for a virtual-reality experience — no headset required.