Ninety years ago, in a bid to have his equations describe an unchanging universe, Einstein introduced the concept of dark energy, an omnipresent antigravitational force pushing the universe apart. Ten years later, when astronomer Edwin Hubble (later of telescope fame) showed that the universe wasn’t static at all, Einstein tried to take it back. But over time, it turned out that dark energy wasn’t such a bad idea at all—in 1998, scientists uncovered the first hard evidence that it exists. The only hitch? No one has the slightest idea what causes it.

Hoping to change that, a team of scientists stationed in Antarctica has run a successful test of the South Pole Telescope, a 10-meter-wide behemoth that just might solve the mystery of dark energy. Nine institutions came together to develop the telescope, with the $19.2-million bill picked up primarily by the National Science Foundation. Assembly required pilots from the New York Air National Guard, aircraft from Operation Deep Freeze (the U.S. military’s ongoing mission in Antarctica), and round-the-clock construction since November in the unrelenting cold of one of Earth’s most hostile climates. Finally, on February 16, the group collected what’s known as first light. They aimed the telescope skyward and saw . . . light—and dark, and Jupiter.

When testing is completed, the telescope will be used to detect ripples in the cosmic microwave background that reflect the history of dark energy—how long it has been around, how its strength has changed since the universe began, and so on—all in the name of settling the theoretical cage match that has surrounded one of astrophysics’ most mind-boggling concepts. Einstein! Hubble! Round one: fight! —Abby Seiff