This week in science, we learned about how climate change is endangering baby penguins, took a peek at some of the science behind the savage ballet of football, and found out that lingering traces of the banned pesticide DDT may play a role in Alzheimer’s disease. But there was a lot more going on this week; here’s a roundup:

Researchers have created the sonic equivalent of a one-way mirror. The “acoustic circulator” allows someone to listen in to sound waves without being heard. [LiveScience]

The mass winter migration of monarch butterflies from the U.S. and Canada to Mexico may soon be a thing of the past. The most recent counts show that the smallest number of migrating monarchs yet. Potential culprits for the decline include logging in Mexico, which has decimated the monarchs’ favored winter home, the oyamel fir tree; and herbicide-heavy industrial farming, which is wiping out milkweed plants where the butterflies lay their eggs. [Washington Post]

Happy Chinese New Year! Here’s a good explanation for why the Year of the Horse didn’t start on Jan. 1: it comes down to astronomy. [Christian Science Monitor]

A climate scientist’s defamation lawsuit could deal a killing blow to conservative publication National Review. Writer Mark Steyn accused Penn State scientist Michael Mann of fraud and compared him to Jerry Sandusky, the Penn State assistant football coach and convicted child molester. Defamation suits are hard to win in the U.S., but National Review has suffered from some setbacks: judges have refused to dismiss the case, prompting Steyn to write a furious blog post. Steyn and the law firm representing him have also parted ways. And, like most publications, National Review likely doesn’t have vast cash reserves to keep funding a lawsuit or pay for a substantial settlement. [The Week]

The U.S. military spent $5 billion trying to develop a “universal camouflage” pattern that would work across all environments that a soldier might encounter. But this effort seems to be largely wasted; an in-depth examination of the science of camouflage explains why. [Gizmodo]

Maybe streaming services like Netflix and Hulu have killed your desire for Blu-ray discs. No matter; Facebook might be basing its data storage system on them soon. Blu-ray discs might be a better way for the company to put vast amounts of data in long-term storage (discs are certified as reliable for at least 50 years, with some rated for 1,000 years) and could be better-suited for recovering data after a crash than hard disk drives. [Ars Technica]

Scientific American calls for an end to the U.S. ban on psychoactive drug research. [Scientific American]

The Federal Aviation Administration has grounded the idea of drone-delivered beer -- for now. A microbrewery in Minnesota planned on testing the service for ice fisherman, but the FAA has put the kibosh on all commercial drone projects until their policies are reviewed and possibly changed next year. [The Verge]