In 2005, astronaut Leroy Chiao was commander of the International Space Station for six and a half months. During a spacewalk with cosmonaut Salizhan Sharipov, the two were installing navigation antennas. They were 230 miles above Earth, traveling at over 17,000 miles per hour, when something unusual caught Chiao's eye.
"I saw some lights that seemed to be in a line and it was almost like an upside-down check mark, and I saw them fly by and thought it was awfully strange," Chiao told The Huffington Post.
Chiao's fellow spacewalker, Sharipov, hadn't seen the lights because he was facing the opposite direction.
This experience, recreated in the above video (and still image below), launches "NASA's Unexplained Files," one of several programs presented as part of Science Channel's week-long "Are We Alone?" series, beginning March 2.
A down-to-Earth explanation is offered for Chiao's sighting: the bright lights of a fishing boat hundreds of miles below him. But is that the only possible interpretation of what the astronaut saw?
To read more and view the video, click here.