Certain elements on the surface emitted X-rays when the sun zapped Eros with an intense burst of radiation for 30 minutes on May 4.

CNN: Asteroid Eros resembles 'building blocks' of Earth

In an article headlined " 'Aliens exist' say real-life X-Files, " the London tabloid The Sun said the memo appeared to back the claim that extraterrestrials landed in Roswell, New Mexico.

CNN: FBI's 'flying saucers' online memo intrigues public

When the sun is in this state, it also sends less energy out in the soft X-ray and extreme ultraviolet parts of its spectrum.

MSN: Earth's upper atmosphere cooling dramatically