Earth is rapidly being wired with fiber-optic cables—inexpensive, flexible strands of silicon dioxide that have revolutionized telecommunications. They’ve already crisscrossed the planet’s oceans, linking every continent but one: Antarctica. Now, fiber optics has arrived at the continent, but to measure ice sheet temperatures rather than carry telecommunication signals. A team of scientists using an innovative fiber-optic cable–based technology has measured temperature changes within and below the ice over 14 months. This technology, they say, offers a powerful new tool to observe and quantify melting at the base of the West Antarctic Ice Sheet, the collapse of which may help drive a worldwide increase in sea levels of more than 3 meters.