"The Unexpected Shadow of the Total Solar Eclipse"

Viewers of the recent solar eclipse in Montreal were treated to two surprising phenomena: a sharp shadow caused by a passing airplane just after the eclipse concluded, and a spectacular halo around the partially eclipsed sun. The sharpness of the airplane's contrail shadow was accentuated by the eclipse, while the halo around the sun was unrelated to the eclipse and is a common optical illusion created by ice crystals in the upper atmosphere. These displays can occur frequently and are not limited to polar regions, making them a fascinating phenomenon to watch out for.