Sky watchers, let’s look up at the sky again! If you live in certain parts of the United States and missed the Northern Lights, you may have another chance.
The massive geomagnetic storms across North America are caused by charged particles recently fired toward Earth by the Sun, known as coronal mass ejections (CMEs). The last and most powerful CME continues to hurtle toward the atmosphere Wednesday, and is expected to provide another spectacular night, according to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center.
Approximately 18 states are partially or fully within NOAA’s aurora forecast “view line” for Nov. 12. The view line marks the southernmost point where the aurora can be seen on the northern horizon.
States expected to see the Northern Lights this week
If the weather is clear, experts say the sky show should be visible in parts of Alaska, Idaho, Illinois, Iowa, Maine, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New York, North Dakota, Oregon, South Dakota, Vermont, Wyoming, Washington and Wisconsin.
If you can’t see the graphic, click here to view it.
How the aurora is created
In the north or south pole regions of the earth, the aurora borealis is a dazzling stream of light. Magnetic storms caused by solar activity, such as solar flares (sun explosions) and coronal mass ejections (ejected gas bubbles), are responsible for these natural light illuminations. According to NASA, the solar wind moves high-energy charged particles from these phenomena away from the sun.
The University of Alaska and NOAA track auroras using the Kp Index, a global auroral activity index with a scale of 0 to 9. It measures variations in the Earth’s magnetic field associated with a specific geographic location.
According to NOAA’s Space Weather Prediction Center, the Kp index is expected to peak at 8.7 this week. See NOAA’s 3-day forecast for the latest timing breakdown.
When these particles enter the Earth’s magnetosphere, substorms occur. Oxygen and nitrogen particles on Earth collide with fast-moving particles as they impact the thin upper atmosphere. As these air particles release the energy they gained from their collisions, each atom begins to glow in a different hue.
How Earth’s magnetic field acts as a shield
We are protected from the solar wind by an invisible barrier created by the Earth’s magnetic field. When the solar wind becomes stronger, it can cause disturbances in the Earth’s magnetic field. When the stream of particles interacts with the gases in the planet’s magnetic field, beautiful aurorae are produced.
What causes the aurora borealis and its colors?
When the sun releases solar flares, plasma particles are carried toward Earth.
Atoms in air molecules in the Earth’s magnetic field are stimulated when charged electrons from the sun collide with them. As the molecules settle, they emit light. Green and red light is emitted by oxygen. The colors of nitrogen are blue and purple.
SOURCE NOAA Space Prediction Center, European Space Agency, Weather Channel, USA TODAY Investigation
