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May Aurora: Earth Image of the Week May 14, 2010
Astronaut photo of Northern Lights over Chicago
The Northern Lights can be seen swirling over Canada to the north of Lake Michigan.
The Earth’s upper atmosphere was bombarded in early May by charged particles streaming toward the planet from the eruptions of solar flares.

The surface of the sun has become progressively more active over the past several months as the 11-year cycle of sunspot activity began its upward swing from a near-record low.

According to Spaceweather.com, more than half a dozen flares erupted from one active region on May 8 alone.

On May 9, Japanese astronaut Soichi Noguchi uploaded the image to the right to Twitter, which he took from the International Space Station as it passed over the Southeastern United States.

The night lights of metropolitan Chicago and other cities in the region appear in contrast to the non-illuminated surface of Lake Michigan and outer space well above.

The green glow of the Northern Lights appears to be dancing directly over Wisconsin and Michigan, but was actually positioned well to the north over Canada.

Just as neon gas glows when an electrical charge is passed through it, various elements in Earth’s atmosphere shine when excited by the charged particles of the solar wind.

Oxygen, at about 60 to 125 miles above the surface, gives off a yellow-green glow. Oxygen above 125 miles in altitude gives off a red glow.

Photo: Soichi NoguchI - International Space Station