Reading Passage: A Signal from Europa

Ravi and Camila were checking the instruments aboard the research ship Horizon when a soft beep sounded from the communications panel. The ship was orbiting Europa, one of Jupiter’s icy moons. Their mission was to collect information about the moon’s surface and send it back to Earth. On the screen, a narrow green line appeared, vanished, and then appeared again. Camila checked the ship’s schedule. “No message is expected right now,” she said. Ravi studied the instrument readings. The signal seemed to come from beneath a thick layer of ice, but the ship’s equipment could not tell whether it was natural or made by a machine. Andre, the mission specialist, suggested that they send a short reply. Before doing so, the crew compared the signal with readings from their other instruments. The pattern repeated every twelve seconds, and it did not match the usual bursts of static. Still, they could not be certain what had caused it. The crew sent a simple pulse and waited. For several minutes, nothing happened. Then the green line flashed twice. Ravi recorded the time and the exact pattern. “We don’t know what it means yet,” Camila reminded him, “but now we have something new to investigate.” The three teammates began preparing a careful report for the scientists on Earth.