NASA's Polar spacecraft saw both the aurora borealis and aurora australis (northern and southern lights) expanding and brightening around midnight ET on July 27.

The colorful lights, green in this photo, were seen by skywatchers as far south as Iowa and part of California and New York.

The display was created by a mid-sized coronal mass ejection (CME) that shot out from the Sun on July 25. Intense coronal holes on the solar surface also contributed to the influx of charged particles that interacted with Earth's protective magnetic field and atmosphere.

The aurora, also known as the Northern and Southern Lights, form when solar particles and magnetic fields pump energy into the Earth's magnetic field, accelerating electrically charged particles trapped within. The high-speed particles crash into Earth's upper atmosphere (ionosphere) over the polar regions, causing the atmosphere to emit a ghostly, multicolored glow.

-- SPACE.com Staff

Credit: NASA/The University of Iowa