Watch international air traffic

Airlines are flying again, despite the ash cloud that’s spewing from the volcano in Iceland. Is it because it’s safe to fly or because they need the money?

You can follow the extent to which the planes are flying (or not) on FlightExplorer.com

Planes are flying into and out of Amsterdam, but at last check, the UK is a dark place where air traffic is concerned. It is supposed to reopen at 4 p.m. CT. (Update: It is now reopened)

How safe is this? Nobody really seems to know, the Associated Press reports, because nobody’s ever done this on a widespread basis before.

“There are really no facts about risk. It’s just how we interpret the information we have,” said David Ropeik, an instructor in risk perception at Harvard and author of the book “How Risky Is It, Really?”

“This is a great example of how the pace of modern technological invention is making a lot more people nervous about just how sure science can be about anything,” he said.

Watching the same people who earlier said it was too dangerous to fly now say it’s safe “is just more proof that risk is a subjective idea,” Ropeik said Tuesday. “It involves a lot more than what people assume it does.”