How starfish move their tiny tube feet, and more…

Starfish don't have brains, and yet they're able to mobilize hundreds of tiny hydraulic tube feet to get around. Now scientists are getting an understanding of just how they do that. PLUS: Atmospheric pollution from an individual rocket re-entry event measured for the first timeHow the Earth’s greenhouse age transitioned into a world with frozen polesWhat is dark matter? The contenders — from WIMPs to dark matter starsQuirks Question: why doesn’t flowing water freeze at the same temperature as still water? (Correction: A previous version of the...