National Geographic : 2017 Feb
Want to take a cosmic Rorschach test? Tilt your head to the side. If you see a pair of bright eyes in the inky depths of space, you’re seeing what a team of astronomers spied last year—a rare formation created by the grazing collision of two spiral galaxies. Galactic sideswipes aren’t un- usual, says lead researcher Michele Kaufman. What is novel are the shapes they can create. Here, the gravitational pull of NGC 2207 (top) produces tides in its companion, IC 2163—as the moon does on Earth. Gas and stars from the edges of IC 2163 then race inward before abruptly slowing down, forming two “eyelids.” A telescope in Chile called the Ata- cama Large Millimeter/submillimeter Array, or ALMA, helped Kaufman and her team see what computers had modeled. “As soon as I saw this data in high resolution,” she says, “I realized it showed us for the first time how an eyelid structure develops.” Of course, the reason we perceive these shapes as eyes in the first place has nothing to do with telescopes. It’s due to pareidolia—a psycholog- ical phenomenon in which we see familiar shapes where none exist. The celestial eyes on this page are 114 million light-years from Earth. Technology and psychology will determine what else pops into view. EYES IN THE SKY By Jeremy Berlin A GLIMPSE OF WHAT’S NEW AND NEXT FURTHER PHOTO: M. KAUFMAN, ALMA (ESO/NAOJ/ NRAO); NASA/ESA HUB- BLE SPACE TELESCOPE In this image the blue represents data from the Hubble Space Telescope; the red is carbon monoxide visual- ized by ALMA.