Microscopic grains of space dust captured by NASA’s Stardust spacecraft appear to have come from interstellar space. These fragile particles, perhaps the first directly captured from outside the solar system, could help researchers understand the building blocks of not only Earth and its siblings but also planets around other stars.
The sample — just seven particles — comes after years of collecting dust and more years of thousands of people analyzing the spacecraft’s take. “Any sane person asks: Why spend years doing this?” says Andrew Westphal, a planetary scientist at the University of California, Berkeley and a member of the Stardust team. “This is about our origin,” he says, “what materials formed the sun, planets and us.”