States across the Northern edge of the U.S. have a chance to see the northern lights (also known as Aurora Borealis) this week, due to geomagnetic activity.
Geomagnetic activity is measured by the planetary K index, or Kp, that includes a range from 0-9. Forecasts from National Oceanic and Atmospheric Administration’s Space Weather Prediction Center show that the aurora borealis Kp will be at a 5 Wednesday. That means that the auroral activity will move further from the poles and become brighter.
NOAA explained that the northern lights are a “result of interactions between the sun and Earth’s outer atmosphere,” and that a similar phenomenon, aurora australis, occurs at the southern hemisphere counterpart.
It starts when sun emits electrically-charged particles called ions, they move away from the sun in a stream of ionized gas called plasma, also known as solar wind. This plasma then comes in contact with the Earth’s magnetic field and the ions become agitated. Some become trapped and interact with the ionosphere around 60 to 80 miles above the Earth’s surface and then start to glow.
“This is the same principal as how a neon sign lights up,” per the NOAA. “As electrons pass through the neon tubing, they glow, thus producing the light in a neon sign.”
These glowing, colorful lights can be beautiful to look at. They can also cause some power disruptions on Earth, particularly in satellite communications as well as radio and TV broadcasts.
While the northern lights are expected to be visible in more states than usual this week – NOAA forecasts show levels close to 6 Wednesday evening and up to 4 through Friday – it is still expected to be easiest to see up north in Alaska. Here is the full list of states where there is a chance to see the lights, according to Space.com and USA Today:
1. Alaska
2. Minnesota
3. North Dakota
4. Montana
5. Maine
6. Michigan
7. Wisconsin
8. Vermont
9. New Hampshire
10. Washington
11. Oregon
12. Idaho
13. New York
14. South Dakota
15. Wyoming
In addition to Kp, Space.com noted that “a key ingredient of aurora activity,” is the Bz value of the Interplanetary Magnetic Field. A string “south” Bz in particular is something to look out for.
“If there is a strong southward Bz, your chances of seeing auroras increase significantly,” said the outlet.
Some other tips for skygazers hoping to see some northern lights magic include picking the right location, looking at the sky when conditions are dark enough, and getting the timing right. NOAA said to find a location pointed to the north pole with a somewhat unobstructed view, such as the top of a hill. It is important to be in a place without city light pollution. To get the best view, skywatchers should look for the aurora within an hour or two of midnight.