Passing glances: choosing a calendar for Mars; a look at Annalee Newitz’s debut SF novel

A question for Elon Musk and the rest of us: What’s the date on Mars? Our first, unthinking impulse may be to say that of course it’s today everywhere—except where, because of that darned International Date Line, it may be tomorrow, or yesterday—and that today is December 4, 2017. But soon we remember that more than one calendar is in use upon Earth; our friends in China may label today differently, as do those who follow Islamic practice or another method. And a little reflection, combined w...