Bolden’s al-Jazeera interview, part 2

The reports of NASA administrator Charles Bolden’s al-Jazeera interview have so far focused mostly on Bolden’s claim that his “foremost” priority at NASA is to reach out to the Muslim world in order “to help them feel good about their historic contribution to science, math, and engineering.”

Though this statement is both idiotic and condescending, I don’t think it was the most idiotic thing Bolden said. Instead, I think the prize-winner is this quote near the end of the interview (at around 21:30), where Bolden describes why we need to find out the make-up of all asteroids:

Is it sand or is it metal? If it is sand we’re not really worried that much about it because it’s probably going to impact the Earth and, you know, go away. Metal would be a bad day. We could have another ice age and instead of the extinction of the dinosaurs it would be the extinction of you and me.

Asteroids made of “sand” are merely going to “go away” if they hit the Earth? I would really like to see the scientific research Bolden is relying on for this statement.