Perfect timing: Yesterday, three astronomers received the news every scientist wants: they would be receiving the physics Nobel Prize for their work in discovering dark energy, a repulsive force that is ramping up the expansion of the universe. So it was somehow fitting that, on the very same day, European Space Agency officials were approving a space mission, called Euclid, that would pin down more precisely dark energy’s key parameters. “It was just coincidence, really,” says David Schlegel, principal investigator for BOSS, a ground-based mission that is also trying to get a handle on the stuff that looks a lot like a cosmological constant, the fudge factor that Einstein introduced in his relativity equations when he thought the universe was static, but later regretted.
Okay, so the prize has nothing to do with ESA’s decision. But will it bolster the case for other dark energy missions? In the United States, NASA, the Energy Department and the National Science Foundation are all trying to get a piece of the action. NASA’s WFIRST is the most expensive mission and the most sought after (it was ranked tops in the US decadal survey), and it’s probably the most capable. But it’s stuck in line behind the James Webb Space Telescope, and so most observers think it doesn’t have a chance of flying at all until the 2020s. The selection of Euclid, a very similar mission that would scoop much of the early science, may put further pressure on NASA to attempt what has failed in the past: a mission merger.
Ground-based dark energy experiments may get a lot more bang for the buck — but even there, money is a problem. LSST, another community favorite that will make major strides in measuring dark energy, still needs cash. In a universe that keeps moving faster and faster, missions like LSST and WFIRST seem to get farther and farther away. “It seems like it’s so far in the future,” says Schlegel.