Tiger, tiger, burning bright...
A new atmospheric phenomenon was caught on video by the crew of the space shuttle Columbia just days before the shuttle broke apart, new findings suggest.
Astronauts relayed the video to NASA in real-time during their 16-day flight. But the agency did not release the full data to researchers until several months after the mission's tragic end on 1 February 2003. All seven crewmembers were killed when the shuttle exploded while re-entering the atmosphere.
Yoav Yair of the Open University in Ra'anana, Israel, and colleagues spent more than a year analysing the video, which was originally taken to study atmospheric dust. But a single frame of the video - representing just 33 milliseconds - shows a mysterious reddish glow in the night sky on 20 January 2003.
"I'm not sure what we saw," says Yair. "I just know it wasn't something we were used to seeing - it was something extraordinary." The glow occurred about 150 kilometres above the ocean near Madagascar and does not appear to be linked with thunderstorms.
That contrasts sharply with other ephemeral events at similar altitudes, which glimmer into being when electrical current travels upward from lightning clouds at altitudes of about 10 km. Called sprites and elves, these events take the shape of jellyfish, downward-pointing carrots, or doughnuts, and tend to occur within a horizontal distance of 70 km from lightning.
But the shuttle's video camera did not see any lightning within 800 kilometres of the unexplained flash, which has been dubbed a TIGER (Transient Ionospheric Glow Emission in Red).
A new atmospheric phenomenon was caught on video by the crew of the space shuttle Columbia just days before the shuttle broke apart, new findings suggest.
Astronauts relayed the video to NASA in real-time during their 16-day flight. But the agency did not release the full data to researchers until several months after the mission's tragic end on 1 February 2003. All seven crewmembers were killed when the shuttle exploded while re-entering the atmosphere.
Yoav Yair of the Open University in Ra'anana, Israel, and colleagues spent more than a year analysing the video, which was originally taken to study atmospheric dust. But a single frame of the video - representing just 33 milliseconds - shows a mysterious reddish glow in the night sky on 20 January 2003.
"I'm not sure what we saw," says Yair. "I just know it wasn't something we were used to seeing - it was something extraordinary." The glow occurred about 150 kilometres above the ocean near Madagascar and does not appear to be linked with thunderstorms.
That contrasts sharply with other ephemeral events at similar altitudes, which glimmer into being when electrical current travels upward from lightning clouds at altitudes of about 10 km. Called sprites and elves, these events take the shape of jellyfish, downward-pointing carrots, or doughnuts, and tend to occur within a horizontal distance of 70 km from lightning.
But the shuttle's video camera did not see any lightning within 800 kilometres of the unexplained flash, which has been dubbed a TIGER (Transient Ionospheric Glow Emission in Red).