You might have thought a defining characteristic of a UFO would be visibility. But thanks to zealous alien hunters doggedly scanning the sky with night-vision cameras, a new class of flying objects that only emit infrared light has emerged from the darkness. Are they spies from the great beyond?
"Some people claim to see actual battles between UFOs up in the sky, using night-vision equipment," the ufologist Robert Sheaffer told Life's Little Mysteries .... http://www.livescience.com
