Contrails Harmful?

"After a lifetime of enjoying contrails, it came as a surprise to me to learn recently that something so ephemeral may not be a harmless by-product of the jet age but may in fact impact the climate"

-Peter Tyson,
from The Contrail Effect
PBS NOVA article

Just Because They Can

"An international team of scientists under the direction of Brian Whalen of the National Research Council of Canada successfully blew a temporary hole in the aurora borealis and then sent an instrument carrying rocket through the hole"

February 6, 1980

-Astrophysics Data System Harvard University