Mars has become a lot harder to find lately. Ever since we passed the red planet almost a year ago, it’s been getting dimmer; our faster-moving earth increases the distance between the two, leaving Mars farther and farther behind. But you should be able to find it tonight, because the moon will appear alongside it this evening, acting like a kind of cosmic bookmark in the sky. Go outside after sunset and face toward the west. If skies are clear and nothing blocks your view, you should be able to find the moon, a slender crescent a little ways above the western horizon.