Amateur astronomers are puzzling over a seemingly anomalous cloud that has shown up on images of Mars taken over the past few days. Is it really a cloud, or a trick of the eye? Does it really extend 150 miles up from the surface, as some of the observers suggest? And what churned up all that stuff, anyway?
![Image](http://i70.photobucket.com/albums/i99/gibbj77/Astronomy/120323-coslog-mars3-1140a.gif)
"And that's how it was for the next ten nights.
A flare, spurting out from Mars - bright green, drawing a green mist behind it - a beautiful, but somehow disturbing sight.
Ogilvy, the astronomer, assured me we were in no danger. He was
convinced there could be no living thing on that remote, forbidding planet."