So today the mystery of the aurora is not so mysterious as it used to be. Oxygen gives off the green color of the aurora, for example. But science says that different gases in Earth’s atmosphere give off different colors when they are excited. The colors in the aurora were once a source of mystery throughout human history. And of course, the lights have a counterpart at Earth’s south polar regions, though there is less land at high southerly latitudes for people to witness the displays. But strong displays can extend down into more southerly latitudes. The lights typically appear in the far north – the nations bordering the Arctic Ocean – Canada, Scandinavian countries, Iceland, Russia and the state of Alaska. Strong displays might also have red, violet and white colors. Most are green in color, but sometimes you’ll see a hint of pink. The aurora often appears as curtains of lights, but they can also be arcs or spirals, following lines of force in Earth’s magnetic field. The shapes of the northern and southern lights The molecules give off light as they calm down. When charged particles from the sun strike air molecules in Earth’s magnetic field, they cause those molecules’ atoms to become excited. The aurora works on the same principle, but at a far vaster scale. That’s why these signs give off their brilliant colors. Electricity excites the atoms in the neon gas within the glass tubes of a neon sign. What happens in an aurora is similar to what happens in the neon lights we see on many business signs. Then when an electron moves back to a lower-energy orbit, it releases a particle of light or photon. When charged particles from the sun strike atoms in Earth’s atmosphere, electrons move to higher-energy orbits, further away from the nucleus. What does it mean for an atom to be excited? Atoms consist of a central nucleus and a surrounding cloud of electrons encircling the nucleus in an orbit.
When charged particles interact with Earth’s atmosphere When the charged particles from the sun strike atoms and molecules in Earth’s atmosphere, they excite those atoms, causing them to light up. But if Earth is in the path of the particle stream, our planet’s magnetic field and atmosphere react from the impact. Because our sun is 93 million miles away (150 million km), the eruption we witness on the sun can take several days to reach our atmosphere. Storms on the sun that cause events such as coronal mass ejections and solar wind from coronal holes send charged particles hurtling across space. In fact, the bright blasts of activity on the sun are directly linked to these wispy, elusive lights we see in the night sky. You may have noticed more aurora alerts lately as the sun has become more active. I taped the lens and got tack sharp stars compared to pics taken on the previous night.” Thank you, Kathie! What causes an aurora?Īuroras appear near both the north and south poles as the aurora borealis and the aurora australis. We barely saw the lights, but the camera did! This taken on a brief appearance on a second night of the lights. Katie wrote: “I was thrilled that after maybe 60-plus years I was able to take a picture of the aurora. | Kathie O’Donnell in Rapid City, South Dakota, captured this photo on September 4, 2022.