Why does the universe look the way it does? Sarah T. Stewart thinks she knows the answer. “It all comes down to big things running into each other,” she says. Space is a collection of battered rocks, and Stewart studies their scars and shapes. A planet’s pockmarks can be used to predict its age—if it has many, it’s probably been around for a while—and its dimensions can hint at what might lie beneath the ground. “I use the way craters look,” she explains, “to learn about the planet they’re on.”
Two pinpoints of light represent black holes in the center of this combined X-ray/optical image
Colliding black holes may prove more interesting to scientists than the immovable object versus the unstoppable force. New data from NASA's Chandra X-ray Observatory has combined with optical images from Hubble to show off a merging black hole pair in all its glory.