"That's an argument in favor of it being a local cause-- not extraterrestrial. I don't see how saying aliens did it-- with no evidence to prove or even circumstantially support it-- is any better than throwing up our hands and saying we don't know."

She frowns, glancing back at the screen.

"The fact that science hasn't yet uncovered an answer doesn't mean it's failed her. It means there's still work to be done."