On May 10th, and 11th, lights flowed across the sky as most Americans took pictures with their eyes glued to the stratosphere. On the 11th-13th of May the aurora borealis was supposed to be visible throughout areas of the world, including places where the northern lights usually can’t be seen. “There were sightings in all 50 states. Some of them were low on the horizon more of a glow, seeing the big curtains that we saw here is usually only seen farther north,” said CHS science teacher Mr. Connor.
Mr. Connor explained the phenomena. A solar cycle lasts about eleven years. Once the cycle finishes, the sun’s magnetic field flips. This means the sun’s north and south poles switch places. Right now, we are approaching a solar maximum, though it has not peaked yet. During the solar cycle, giant eruptions on the sun increase. These eruptions have effects on earth: they can cause the aurora borealis, or the northern lights. There was a coronal mass ejection (a eruption on the sun), when the protons and plasma released from the mass ejection hit the magnetic field, it will interact with the photons, if you have those photons coming in while the polarity of the magnetic field is in opposition they call that the BZ scale. The BZ scale is usually at about positive 20, but when it dips to negatives the night sky puts on a big light show. During the recent aroura the BZ scale was around negative 30. “In our area, if you get a KP scale of 6 or higher, you're going to see a possibility of northern lights, but you won't see anything unless the polarity is opposing the direction of the incoming current. So, if the BZ is not negative you usually won't see anything this far south and everything just lined up perfectly that way,” explained Mr. Connor.
“The more powerful storms excite more molecules in the earth's atmosphere, like oxygen and nitrogen, and the more they are excited the brighter they are, the more your eyes can see,” said UW Astronomy teacher Mr. Massey.
May 10th and 11th, ribbons of green and purple flew across the sky. Different gases give off different colors when they are heated. The process is taking place in the northern lights, the green visible in the sky is characteristic of oxygen, while purple, blue, or pink is caused by nitrogen. When charged particles collide with high concentrations of oxygen molecules in Earth's atmosphere at altitudes of around 60 to 190 miles, green can be found. When solar particles collide with nitrogen in Earth's atmosphere at an altitude of 60 miles or less, the lights show up as purple or blue. The brightness of the lights depend on how fast the particles are moving from the sun and the strength of the storm. “The more powerful storms excite more molecules in the earth's atmosphere, like oxygen and nitrogen, and the more they are excited the brighter they are, the more your eyes can see,” said UW Astronomy teacher Mr. Massey.
Late September and late March/early April are the best times to see the northern lights, as the aurora is at its most active around the equinoxes in March and September. To be able to see them well, it must be cold and dark. Enthusiasts should try to see them on a night with a cloudless sky. More aurora will likely be visible around Leavenworth in the next couple of years because of the approaching solar maximum. The northern lights will become more active as we approach the next peak of the solar cycle, predicted to be in July 2025.